For the REVO STG III K04 guys............

[GolfRS]

You might want to check your injectors IMO..

[jhines_06gli]

You might want to check your injectors IMO..

Check them for what?
-The mS is spot on on all 4 with no deviation between them.
-The cylinders are completely clean with no build-up on pistons which typically means there is minimal buildup on injector tip.
-The plugs are relatively clean, just have been fouled by fuel for a long time, so they will be replaced today.
-Did a fuel pressure leakdown test to make sure I don't have an injector sticking....passed that.

The intake will be coming off in 5K when I hit 160K miles for routine checking/cleaning of valves and new injector seals as well as my HPFP check/follower service.

But as for checking the injectors, what else can I check with them? If there is an issue with injectors, it's ALL 4 because all 4 cylinders were doing the same thing and the timing retard values were the same for all 4 when the car was acting up.
-J. Hines

[GolfRS]

Check them for what?
-The mS is spot on on all 4 with no deviation between them.
-The cylinders are completely clean with no build-up on pistons which typically means there is minimal buildup on injector tip.
-The plugs are relatively clean, just have been fouled by fuel for a long time, so they will be replaced today.
-Did a fuel pressure leakdown test to make sure I don't have an injector sticking....passed that.

The intake will be coming off in 5K when I hit 160K miles for routine checking/cleaning of valves and new injector seals as well as my HPFP check/follower service.

But as for checking the injectors, what else can I check with them? If there is an issue with injectors, it's ALL 4 because all 4 cylinders were doing the same thing and the timing retard values were the same for all 4 when the car was acting up.
-J. Hines

I am simply suggesting this cause from what i have seen FSI injectors tend to "leak".And you won't find that from injector timing, cause at idle the FSI injectors are operating at the lowest injector time
between 0.55 ms and 0.71 ms.A leaking injector(s) would show as the ECU pulling fuel, but without a
way to reduce the injection time even further, you and up with a "rich state".

You can verify that by simply looking at your lambda adaptation value at block 001 where you will see
the ECU pulling fuel at high negative values especially right after cold start.When my cylinder 2 plug was fouled, changing the #2 injector solved the issue, so checking your plugs for fouling might be a
good place to start....

[jhines_06gli]

I am simply suggesting this cause from what i have seen FSI injectors tend to "leak".And you won't find that from injector timing, cause at idle the FSI injectors are operating at the lowest injector time
between 0.55 ms and 0.71 ms.A leaking injector(s) would show as the ECU pulling fuel, but without a
way to reduce the injection time even further, you and up with a "rich state".

You can verify that by simply looking at your lambda adaptation value at block 001 where you will see
the ECU pulling fuel at high negative values especially right after cold start.When my cylinder 2 plug was fouled, changing the #2 injector solved the issue, so checking your plugs for fouling might be a
good place to start....

My lambda values after replacing and adapting throttle body and changing rail valve and oil is posted on the last page. Drove home and lambda was down to -3.1%. Best it's been since way back when I was Stg. 1 REVO with intake and catback!!! As for the injectors......by doing the fuel pressure residual holding test, I checked the injectors when not active to see if the pintle was staying cracked open and leaking fuel......by VW standards it passed, so hopefully they are good. All seems well and feels like I gained 10-15hp so far. Throttle response is much smoother and hopefully after plugs I'll no longer have misfires above 20PSI. Regardless, the wideband is getting completed this weekend so I can monitor live data ALL the time under all conditions without having to log it.
-J. Hines

[GolfRS]

My lambda values after replacing and adapting throttle body and changing rail valve and oil is posted on the last page. Drove home and lambda was down to -3.1%. Best it's been since way back when I was Stg. 1 REVO with intake and catback!!! As for the injectors......by doing the fuel pressure residual holding test, I checked the injectors when not active to see if the pintle was staying cracked open and leaking fuel......by VW standards it passed, so hopefully they are good. All seems well and feels like I gained 10-15hp so far. Throttle response is much smoother and hopefully after plugs I'll no longer have misfires above 20PSI. Regardless, the wideband is getting completed this weekend so I can monitor live data ALL the time under all conditions without having to log it.
-J. Hines

Do you have the testing procedure somewhere i could have a look at it ?

What exactly are the VW standards ?My rail pressure drops pretty quick but i have
seen cars that do that and others that don't...

[jhines_06gli]

Cannot really send you a direct link to the page as it is security-protected by the VW servers. So you must have login rights to view the stuff, but here is the literature. The VAG 1318 is a fuel pressure gauge in line with the main supply line to the engine. In our case, it hooks up at the quick-connects by the pass. firewall. All you are really checking is that when you shut the car off, does the fuel stay pressurized in the system? Or does it leak off and go somewhere. They never tell you through this that the injectors can be faulty and cause pressure to drop below 3.0BAR, but it can and is most likely cause.....especially on gummed up, high mileage FSI cars and newer TSI engines.

Basically if you drop below the 3.5BAR, then you have a bad rail pressure retention valve, bad HPFP(leaking internally) or leaking injectors. In my case, I had 6.4BAR with engine running, shut it off and waited 10 minutes and it dropped to 5.1BAR.

But here is the info from the VW repair manuals on the procedure:

Residual Pressure

l Fuel pressure OK and the -VAG 1318- is still connected. Checking fuel pressure, refer to → Chapter „Fuel Pressure“.
– Switch the ignition on and off until the fuel pressure on the -VAG 1318- no longer rises.
– Read off the fuel pressure on the -VAG 1318-.
l Specified value: 3.5 to 5.0 bar.
– Watch the pressure drop on the -VAG 1318-.
l After 10 minutes the pressure must not drop below a 3.0 bar decrease.
If the pressure drops further
– Switch the ignition on and off until the fuel pressure on the -VAG 1318- no longer rises.

– Immediately close the shut off valve on the -VAG 1318-. Lever will then point in position -B-.
If Pressure Drops Again
– Check the fuel pipe to high pressure pump for leaks.
If no malfunction can be found:
– Replace the high pressure pump. Refer to → Chapter „High Pressure Pump“.
If Pressure No Longer Drops Now
– Check the fuel line to fuel filter for leaks.
If no malfunctions are found in the fuel line:

– Check the check valve in the fuel delivery unit. Connect the -VAG 1318- with the -VAG 1318/17- between the fuel filter and fuel supply line.
– Open the shut off valve on the -VAG 1318-. The lever points in the direction of flow.
– Switch the ignition on and off until the fuel pressure on the -VAG 1318- no longer rises.
– Read off the fuel pressure on the -VAG 1318-.
l Specified value: 3.5 to 5.0 bar.

– After the pressure has built up, immediately close the shut off valve on the -VAG 1318-.
– Watch the pressure drop on the -VAG 1318-.
l After 10 minutes the pressure must not drop below a 3.0 bar decrease.
If the pressure drops:
– Check valve in the fuel pump is faulty, replace the fuel delivery unit. Refer to → Chapter „Fuel Delivery Unit“.
If the pressure does not drop:
– Pressure relief valve in the fuel filter is malfunctioning, replace the fuel filter.

[GolfRS]

Cannot really send you a direct link to the page as it is security-protected by the VW servers. So you must have login rights to view the stuff, but here is the literature. The VAG 1318 is a fuel pressure gauge in line with the main supply line to the engine. In our case, it hooks up at the quick-connects by the pass. firewall. All you are really checking is that when you shut the car off, does the fuel stay pressurized in the system? Or does it leak off and go somewhere. They never tell you through this that the injectors can be faulty and cause pressure to drop below 3.0BAR, but it can and is most likely cause.....especially on gummed up, high mileage FSI cars and newer TSI engines.

Basically if you drop below the 3.5BAR, then you have a bad rail pressure retention valve, bad HPFP(leaking internally) or leaking injectors. In my case, I had 6.4BAR with engine running, shut it off and waited 10 minutes and it dropped to 5.1BAR.

But here is the info from the VW repair manuals on the procedure:

Residual Pressure

l Fuel pressure OK and the -VAG 1318- is still connected. Checking fuel pressure, refer to → Chapter „Fuel Pressure“.
– Switch the ignition on and off until the fuel pressure on the -VAG 1318- no longer rises.
– Read off the fuel pressure on the -VAG 1318-.
l Specified value: 3.5 to 5.0 bar.
– Watch the pressure drop on the -VAG 1318-.
l After 10 minutes the pressure must not drop below a 3.0 bar decrease.
If the pressure drops further
– Switch the ignition on and off until the fuel pressure on the -VAG 1318- no longer rises.

– Immediately close the shut off valve on the -VAG 1318-. Lever will then point in position -B-.
If Pressure Drops Again
– Check the fuel pipe to high pressure pump for leaks.
If no malfunction can be found:
– Replace the high pressure pump. Refer to → Chapter „High Pressure Pump“.
If Pressure No Longer Drops Now
– Check the fuel line to fuel filter for leaks.
If no malfunctions are found in the fuel line:

– Check the check valve in the fuel delivery unit. Connect the -VAG 1318- with the -VAG 1318/17- between the fuel filter and fuel supply line.
– Open the shut off valve on the -VAG 1318-. The lever points in the direction of flow.
– Switch the ignition on and off until the fuel pressure on the -VAG 1318- no longer rises.
– Read off the fuel pressure on the -VAG 1318-.
l Specified value: 3.5 to 5.0 bar.

– After the pressure has built up, immediately close the shut off valve on the -VAG 1318-.
– Watch the pressure drop on the -VAG 1318-.
l After 10 minutes the pressure must not drop below a 3.0 bar decrease.
If the pressure drops:
– Check valve in the fuel pump is faulty, replace the fuel delivery unit. Refer to → Chapter „Fuel Delivery Unit“.
If the pressure does not drop:
– Pressure relief valve in the fuel filter is malfunctioning, replace the fuel filter.

Hmmm ok maybe i misunderstood what you were saying.....but isn't our working rail pressure
at 49.5 bar ??The 6.4 bar you measured are in the low pressure system, and matches the
rating on the fuel filter.

When i was talking about my rail pressure falling i was referring to the 49.5 bar@ idle, that
gradually falls after engine shut off.

[jhines_06gli]

Hmmm ok maybe i misunderstood what you were saying.....but isn't our working rail pressure
at 49.5 bar ??The 6.4 bar you measured are in the low pressure system, and matches the
rating on the fuel filter.

When i was talking about my rail pressure falling i was referring to the 49.5 bar@ idle, that
gradually falls after engine shut off.

The high side of the fuel system retained by the bleed valve. But that valve is a shut-off safety switch for the rail. It only should open when it exceeds 130BAR. Unless you have a valve that got a piece of trash or something in it, but seems like you would see that effect when it's running under heavy load, not at "engine off". But you are correct with the 50BAR holding pressure of the rail when off. Typically that's what VW told us the rail should stay at.....although we are not supposed to check that manually........we just have to go off what the rail pressure sensor is reading with a scan tool. So I've never seen a gauge reading from the rail itself.

What issues are you having? Hard-start or start-up misfires?
-J. H?ines

[GolfRS]

The high side of the fuel system retained by the bleed valve. But that valve is a shut-off safety switch for the rail. It only should open when it exceeds 130BAR. Unless you have a valve that got a piece of trash or something in it, but seems like you would see that effect when it's running under heavy load, not at "engine off". But you are correct with the 50BAR holding pressure of the rail when off. Typically that's what VW told us the rail should stay at.....although we are not supposed to check that manually........we just have to go off what the rail pressure sensor is reading with a scan tool. So I've never seen a gauge reading from the rail itself.

What issues are you having? Hard-start or start-up misfires?
-J. H?ines

The reason i talked about the high pressure system and the residual pressure after shut off
is the fact injector leaking might as well be the reason for the (excessive) reduction.
This is why i asked you for VW procedures and standards, cause i haven't run into any
high pressure reduction standards and any limit below which a possible injector leak
is a possibility.As i said i have seen cars that hold pressure, and cars that don't.However
none of them had the injectors changed and retested to see if that was the cause for the
rapid reduction.

You could easily do the test using VCDS after shutting off engine and measuring the
time it takes to reach the lowest pressure value.

On another note, remember a leaking injector isn't easy to diagnose epsecially on the FSI.
One way as i said is to check the plugs for fouling, which was my case.Another way is to
change them all and hope for the best...Using the wideband isn't gonna do any good
(as it doesn't in the ECU's case) cause it "sees" the resulting fuel from all the cylinders
reaching the exhaust, and cannot discriminate between cyl 1, cyl 2 etc...So you might have
1 or 2 injectors leaking, and the car seeing a rich state, while the other 2 cylinders might be seeing
a lean state cause of the overall fuel being pulled from what the O2 sensor sees.

The way i see it that could also explain misfires at high boost.I used to get that and found plug
gapping helped, but this is not the solution to an existing issue....

[jhines_06gli]

Leaking injector or "mis-spraying" injector would explain the issue. I've dealt with that, but caused issues across the whole RPM band in that one cylinder. Usually you can monitor it through the ignition retard MVB(20 I believe). By watching this, I could see that all 4 of my cylinders would do the exact same thing as I climbed in RPM and boost. If I had one cylinder pulling a lot more time than the rest because of an injector(puddling fuel), then it would seem a lot more likely. As I said, the intake will be off in 5K miles, which it doesn't take me long at all to put 5K on the car!! So I'll check the spray patterns then while i clean everything up.

As for the plugs, mine too hold their gap. But I have had everything set at 32, now I'm going to close it up a little and make the spark hotter since I increased my boost and my fuel pressure. I need to get a solid log with new plugs and see what my lambda values and fuel pressures are actually at. But from driving this morning, the throttle body REALLY helped!!! Or it's just a freak accident that everything got a lot better after replacing it and doing a few maint. items.
-J. Hines

On the topic of spark plugs.......is anyone running a one-step colder plug than OEM? OEM is a heat range 7, just curious if anyone that is running high boost has stepped it down? I've had pretty good luck with the OE plugs so far when my car was running right, so hopefully they'll be back to lasting at least 20-30K miles!!

[bostonaudi1]

Leaking injector or "mis-spraying" injector would explain the issue. I've dealt with that, but caused issues across the whole RPM band in that one cylinder. Usually you can monitor it through the ignition retard MVB(20 I believe). By watching this, I could see that all 4 of my cylinders would do the exact same thing as I climbed in RPM and boost. If I had one cylinder pulling a lot more time than the rest because of an injector(puddling fuel), then it would seem a lot more likely. As I said, the intake will be off in 5K miles, which it doesn't take me long at all to put 5K on the car!! So I'll check the spray patterns then while i clean everything up.

As for the plugs, mine too hold their gap. But I have had everything set at 32, now I'm going to close it up a little and make the spark hotter since I increased my boost and my fuel pressure. I need to get a solid log with new plugs and see what my lambda values and fuel pressures are actually at. But from driving this morning, the throttle body REALLY helped!!! Or it's just a freak accident that everything got a lot better after replacing it and doing a few maint. items.
-J. Hines

On the topic of spark plugs.......is anyone running a one-step colder plug than OEM? OEM is a heat range 7, just curious if anyone that is running high boost has stepped it down? I've had pretty good luck with the OE plugs so far when my car was running right, so hopefully they'll be back to lasting at least 20-30K miles!!

Well this was interesting thread, as I have a K04 installed, but am still on stock fueling with Revo Stg 2 tune. Was on fence to go S3 injectors and Uni tune, or stay with Revo and install RS4 injectors. So engine more or less running correctly now with the RS4's? No bad rich conditions?

[jhines_06gli]

Well this was interesting thread, as I have a K04 installed, but am still on stock fueling with Revo Stg 2 tune. Was on fence to go S3 injectors and Uni tune, or stay with Revo and install RS4 injectors. So engine more or less running correctly now with the RS4's? No bad rich conditions?

No more rich right now......-3.1%. Hopefully new plugs with gap closed a little for a hotter spark will go in tomorrow AM. That should correct my high RPM stumble, but MIL off all week, so hopefully it's solved. Car feels AWESOME!!!!

[joeyvdubGLI]

No more rich right now......-3.1%. Hopefully new plugs with gap closed a little for a hotter spark will go in tomorrow AM. That should correct my high RPM stumble, but MIL off all week, so hopefully it's solved. Car feels AWESOME!!!!

Congrats! I was rooting for you man, lol.

Sent from my SCH-I510

[bostonaudi1]

No more rich right now......-3.1%. Hopefully new plugs with gap closed a little for a hotter spark will go in tomorrow AM. That should correct my high RPM stumble, but MIL off all week, so hopefully it's solved. Car feels AWESOME!!!!

That's great news. What do you run boost/timing/fuel settings at with the K04 tune - the normal 6-4-9 more or less?

[GolfRS]

No more rich right now......-3.1%. Hopefully new plugs with gap closed a little for a hotter spark will go in tomorrow AM. That should correct my high RPM stumble, but MIL off all week, so hopefully it's solved. Car feels AWESOME!!!!

-3.1% shows the car is still pulling fuel, indicating a rich condition.

It may not be enough to trigger a CEL but still shows everything isn't perfect.

You were just used to running so rich, you are presently satisfied with
what you are getting.

There is stll work to be done.

[rracerguy717]

-3.1% shows the car is still pulling fuel, indicating a rich condition.

It may not be enough to trigger a CEL but still shows everything isn't perfect.

You were just used to running so rich, you are presently satisfied with
what you are getting.

There is stll work to be done.

-3.1 @ PT is not bad its about normal with RS4 injectors. +/- 20 triggers CEL and running that rich is gonna cause knock / timing pull.

[bostonaudi1]

-3.1 @ PT is not bad its about normal with RS4 injectors. +/- 20 triggers CEL and running that rich is gonna cause knock / timing pull.

So do these injectors normally idle a little rich even with everything OK?

[rracerguy717]

So do these injectors normally idle a little rich even with everything OK?

My car dosnt I would go with the results of people running the same sw as the OP. IMO if the ECU is cracking open the TB to help control fuel trims then its running to rich. My car @ idle has 24" of vacuem rock steady smooth no hunting for idle . Bob G

[GTI08MKV]

I have the same problems! Im k04. Revo stage 3 rs4 injectors all bolt-ons bsh race catch can kmd hpfp etc... so my car stalls in the winter smokes like hell sometimes@ a stop light it'll just ooze out smoke (this is a rare occurance but concerned) im no mechanic appreciate any help! O and my settings are 9-6-9 thanks

[chris@revotechnik]

-3.1% shows the car is still pulling fuel, indicating a rich condition.

It may not be enough to trigger a CEL but still shows everything isn't perfect.

You were just used to running so rich, you are presently satisfied with
what you are getting.

There is stll work to be done.

-3% absolutely within spec, a bone stock car that rolled off the assembly line this morning wouldn't even be looked at for having -3% fuel trims. + or - 10% Vw won't even bat an eye at.

In fact VW even says if your fuel trims don't move from 0 something is broken.

[jhines_06gli]

I have the same problems! Im k04. Revo stage 3 rs4 injectors all bolt-ons bsh race catch can kmd hpfp etc... so my car stalls in the winter smokes like hell sometimes@ a stop light it'll just ooze out smoke (this is a rare occurance but concerned) im no mechanic appreciate any help! O and my settings are 9-6-9 thanks

Basically you have my car. I'm K04 REVO Stg III, RS4 injectors, BSH race VTA can, KMD follower, was KMD HPFP(Now prototype HPFP). In cold months my car stalled out on cold-start, blew black smoke at any touch of the throttle.

I just replaced the throttle body......mine had no cracks, no carbon line and I don't use W/M. Guess it just died out. It would adapt fine every time, passed the sweep test every time and everything. But after replacing the throttle body, my car stays right at -3.1% and only blows black smoke when in heavy accel. MVB 107 now runs and passes every time which it hasn't done since I went REVO STG II way back when!! Only issue I had after throttle body was a hard stutter at high boost and high RPM pulls. Felt like a misfire, but would not register. I put new OE plugs in it and closed the gap down to 26 and it's a beast now. No issues since then.....so hopefully it'll be good through the Winter while I make decisions on going bigger.
-J. Hines

P.S. Check your throttle body and let us know what the part number is. If you have the early one then I'd def. say it's bad. The Audi BT guys are putting a hp number of about 300-350 on our throttle bodies. After that they seem to sh*t out. INA Motorsports has a fix for the issue. If I go through another throttle body I'll be going that route and getting the RS4 throttle body built up.

[GolfRS]

-3% absolutely within spec, a bone stock car that rolled off the assembly line this morning wouldn't even be looked at for having -3% fuel trims. + or - 10% Vw won't even bat an eye at.

In fact VW even says if your fuel trims don't move from 0 something is broken.

Deviating from 0 means the car's ECU sees something through the sensors (the MAF or
O2 sensor for example) and is trying to compensate for it.
Yes VW has set a limit of -+24% to initiate a CEL but that doesn't mean running
at -+22% is ok.I wouldn't even consider the 10% example you gave as "within spec".

This is like you telling all of us that a bad injector that causes a rich condition is OK
to have, simply because the ECU might be "trying" to compensate for it, if that
compensation is at -10% .Or that a bad MAF that is causing trims to go crazy is ok to use cause if it deviates "only" 10% then it's ok....Or a bad O2 sensor that might also effect trims is also ok.
And what about a vacuum leak ??

Trims can ( and should) be used for diagnostic purposes, they are not just pretty numbers in VCDS.
You stating 10% is normal (and VW also approves it) is ridiculous.

One of these days Chris you have to learn to stop worrying about how people are gonna pick up the
phone, call "support" and bust your balls cause they think something might not be right.Cause it might as well NOT BE.Giving false reassurances isn't gonna deter people from looking out for
their cars.This is (or was...whatever) your job.Get over it....

[chris@revotechnik]

GolfRS, on this matter you couldn't be more wrong. Just stop now.

-3% fuel trims is 100% acceptable by VW, by us and by any other tuner on the planet.

If you don't consider +-10% to be in spec then you need to put a call into Bosch, the engineers who designed your engine, and the engineers who tuned it for VW, as well as VWs tech support in whatever country you are in because this is what THEY say.

[GolfRS]

GolfRS, on this matter you couldn't be more wrong. Just stop now.

-3% fuel trims is 100% acceptable by VW, by us and by any other tuner on the planet.

If you don't consider +-10% to be in spec then you need to put a call into Bosch, the engineers who designed your engine, and the engineers who tuned it for VW, as well as VWs tech support in whatever country you are in because this is what THEY say.

As far as VW is concerned, the failing flaps actuators were also "acceptable", and they
even tried to cover up with a flash, but that doesn't mean they shouldn't change them.

As far as VW is concerned a failing cam follower is also "acceptable" or they would have
found out a solution around it.But guess what Chris...newsflash...cam followers fail BAD.

So to your -3% argument i say BS.A -+3% fuel trim might as well indicate a vacuum leak,
a bad injector, a failing MAF, a failing O2 sensor and the list goes on...Are you suggesting
people rely on your professional opinion, and close their eyes to a possible existing issue ?

Believe me if i lived in the U.S. and had decided to go Revo, you would be the last
person i would call for.... "SUPPORT"...And believe me i am not alone on this one....

[jhines_06gli]

As far as VW is concerned, the failing flaps actuators were also "acceptable", and they
even tried to cover up with a flash, but that doesn't mean they shouldn't change them.

As far as VW is concerned a failing cam follower is also "acceptable" or they would have
found out a solution around it.But guess what Chris...newsflash...cam followers fail BAD.

So to your -3% argument i say BS.A -+3% fuel trim might as well indicate a vacuum leak,
a bad injector, a failing MAF, a failing O2 sensor and the list goes on...Are you suggesting
people rely on your professional opinion, and close their eyes to a possible existing issue ?

Believe me if i lived in the U.S. and had decided to go Revo, you would be the last
person i would call for.... "SUPPORT"...And believe me i am not alone on this one....

Alright.......enough with the back and forth....lol This thread was about the failing throttle body issues and we have gotten to the bottom of that. Still don't know what exactly failed. From the looks of the inside of the old throttle body(where the gears are), I would say moisture got somewhere because there is some brown dust on the cover that looks a lot like rust dust. But bottom line is the car is fixed......well at least this issue. Now just keep driving til the next issue raises it's ugly head.

As for the fuel trims, I'll put in my $.02 and leave it at that. Those values in MVB 33 that you are looking at for the fuel trims of the front O2 are a live-data reading of the "leftovers" of combustion. 0.00% being a PERFECT operating engine, the values should be constantly changing around that 0.00% when the vehicle is operating in closed loop. Now what VW told us in the engine diagnostics class(not that everything they say is 100% true) was that you have a normal operating window of +3/-3% that is acceptable baseline for a good engine. By good engine, that means the "Suck/Squeeze/Bang/Blow" components needed for combustion are all there and working properly. By the +3/-3, that means you should constantly see MVB 33(Front O2) switching between ranges of +3 and -3 on a rapid basis at idle. That means the ECM is doing constant adjustments to keep the fuel trims as close to possible as it can. Every single stroke and every single cylinder will create a different amount of C0/C02/O2/N2/etc. because each cylinder gets a different variation of air coming in and has a different variation of air going out. The MVB is just saying that the O2 is switching telling the ECM to do what it needs to in order to keep the values switching around 0.00% to keep a constant value. No combustion in an engine is the same......it's a constantly changing cycle that produces an "average" that we can monitor to see what our engine is doing on average and what we need to do in order to get it closer to perfect if there is an issue.

One FSI may switch around -0.08% and +1.2% while in a different atmosphere or different weather condition the SAME EXACT car might switch between -3.1% and +2.8%. The numbers mean nothing as long as they are switching back and forth and are withing the bottom end of the scale. All the MIL is there for is a legal obligation!!! The MIL MUST eliminate whenever the amount of exhaust emissions produced by the car exceeds 150% the amount mandated for the vehicle class by the EPA/Federal DMV.
-J. Hines

[GolfRS]

Alright.......enough with the back and forth....lol This thread was about the failing throttle body issues and we have gotten to the bottom of that. Still don't know what exactly failed. From the looks of the inside of the old throttle body(where the gears are), I would say moisture got somewhere because there is some brown dust on the cover that looks a lot like rust dust. But bottom line is the car is fixed......well at least this issue. Now just keep driving til the next issue raises it's ugly head.

As for the fuel trims, I'll put in my $.02 and leave it at that. Those values in MVB 33 that you are looking at for the fuel trims of the front O2 are a live-data reading of the "leftovers" of combustion. 0.00% being a PERFECT operating engine, the values should be constantly changing around that 0.00% when the vehicle is operating in closed loop. Now what VW told us in the engine diagnostics class(not that everything they say is 100% true) was that you have a normal operating window of +3/-3% that is acceptable baseline for a good engine. By good engine, that means the "Suck/Squeeze/Bang/Blow" components needed for combustion are all there and working properly. By the +3/-3, that means you should constantly see MVB 33(Front O2) switching between ranges of +3 and -3 on a rapid basis at idle. That means the ECM is doing constant adjustments to keep the fuel trims as close to possible as it can. Every single stroke and every single cylinder will create a different amount of C0/C02/O2/N2/etc. because each cylinder gets a different variation of air coming in and has a different variation of air going out. The MVB is just saying that the O2 is switching telling the ECM to do what it needs to in order to keep the values switching around 0.00% to keep a constant value. No combustion in an engine is the same......it's a constantly changing cycle that produces an "average" that we can monitor to see what our engine is doing on average and what we need to do in order to get it closer to perfect if there is an issue.

One FSI may switch around -0.08% and +1.2% while in a different atmosphere or different weather condition the SAME EXACT car might switch between -3.1% and +2.8%. The numbers mean nothing as long as they are switching back and forth and are withing the bottom end of the scale. All the MIL is there for is a legal obligation!!! The MIL MUST eliminate whenever the amount of exhaust emissions produced by the car exceeds 150% the amount mandated for the vehicle class by the EPA/Federal DMV.
-J. Hines

What both you and Chris are not taking into account when talking about trims and their meaning is that you are both talking about "normal" operating conditions, which indeed vary between engines,
hence the "normal" deviation, but you fail to mention what happens when a hardware failure like those i mentioned above occurs.In that sense, a car may go from +-0.08 to +-3%, but what heppens when the same deviation occurs with the ECU compensating for a bad MAF ?Or a leaking injector ?
Accepting standards is ok when you are talking about normal operating conditions, but to use such
a generalization, you would first have to made sure the engine is also running as it should.

A leaking injector might, and might not cause severe enough engine malfunction to
force someone to check for hardware failure.The same goes for a failing TB, a bad O2 sensor etc.
Trims are a good way to monitor the engine and look out for possible and upcoming failures.
I was battling with a bad idle for the best of 50K miles that turned out to be a failing cam chain
tensioner.All that time my trims were within spec.Does that mean my engine was running OK ?

As i said above the trims are the ECU's opinion on how the engine is running.You might be
within whatever specs the techs think are "normal" but that doesn't mean your engine is
running fine.A deviation (especially when there was none before, or at least not by that much)
is a sign of a change in the engine's function, and IMO is not something one should leave
without investigating further.

[chris@revotechnik]

What both you and Chris are not taking into account ......

What you are not taking into account is that J and I both actually know what we are talking about.

I'm sorry but you are so off base on your assumptions on fuel trims and you are so stubborn as usual that you will never understand this. There is no point in continuing, beyond saying please stop trying to make the forum members dumber.

[GolfRS]

What you are not taking into account is that J and I both actually know what we are talking about.

I'm sorry but you are so off base on your assumptions on fuel trims and you are so stubborn as usual that you will never understand this. There is no point in continuing, beyond saying please stop trying to make the forum members dumber.

Once again this is your answer to everything coming your way..."I know what i'm talking about...you don't".

Exactly WHO certified that about you ??

Yourself ?? LOL

If you don't have an answer, it's better not to answer at all.You protect your integrity better that way...

[joeyvdubGLI]

This thread WAS good...

[jhines_06gli]

This thread WAS good...

haha......just waiting for the lockdown. But yes, it started out VERY informative. Everyone just take notes of the good points.

[chris@revotechnik]

Exactly WHO certified that about you ??

Depending on which engine/Vehicle I have factory training with both VW and Audi. Your training and certification comes from?

Aside from all that i have worked on thousands of VWs/Audis over the last 10+ years. Maybe a small handful have had fuel trims under 3% on a regular basis. Even if i was never trained or never worked along the side of the factory engineers that VW/Audi send to dealers to work with techs just in experience alone I am well a head of you on this matter and can say that you are off base in your assumptions that a fuel trim of -3% is bad.


Bottom line you don't have a clue, your unfortunate need to be wrong on every topic you become involved in just confuses people and derails the thread from being further helpful to anyone. I'm sorry that you cannot handle being told (again and again and again) that you are way off base. I suggest actually doing some studying on the topics you attempt to get involved with, it will prevent me and others from constantly having to tell you that you're wrong.


Go scan the next 10 VWs you see and let us know what the fuel trims are, you'll be shocked but I won't be.

[GolfRS]

Depending on which engine/Vehicle I have factory training with both VW and Audi. Your training and certification comes from?

Aside from all that i have worked on thousands of VWs/Audis over the last 10+ years. Maybe a small handful have had fuel trims under 3% on a regular basis. Even if i was never trained or never worked along the side of the factory engineers that VW/Audi send to dealers to work with techs just in experience alone I am well a head of you on this matter and can say that you are off base in your assumptions that a fuel trim of -3% is bad.


Bottom line you don't have a clue, your unfortunate need to be wrong on every topic you become involved in just confuses people and derails the thread from being further helpful to anyone. I'm sorry that you cannot handle being told (again and again and again) that you are way off base. I suggest actually doing some studying on the topics you attempt to get involved with, it will prevent me and others from constantly having to tell you that you're wrong.


Go scan the next 10 VWs you see and let us know what the fuel trims are, you'll be shocked but I won't be.

Once again you fail to answer my question.

You have a car that under "standard operating conditions" would show a 0.5% trim.
That car suddenly shows a -3% deviation.According to you, this is "within spec", and
no one should take notice.The following day(s) the car experiences an engine failure
due to a failed injector.The owner comes to you and tells you he is going to sue your ass
cause you told him it was nothing, and within VW spec.Do you honestly believe
you can convince him he couldn't have prevented that by further investigating the
sudden change in the trims ??

I don't know what kind of cars you have been working on Chris, but i promise you
i wouldn't let you go near mine...EVER...

[GTI08MKV]

Basically you have my car. I'm K04 REVO Stg III, RS4 injectors, BSH race VTA can, KMD follower, was KMD HPFP(Now prototype HPFP). In cold months my car stalled out on cold-start, blew black smoke at any touch of the throttle.

I just replaced the throttle body......mine had no cracks, no carbon line and I don't use W/M. Guess it just died out. It would adapt fine every time, passed the sweep test every time and everything. But after replacing the throttle body, my car stays right at -3.1% and only blows black smoke when in heavy accel. MVB 107 now runs and passes every time which it hasn't done since I went REVO STG II way back when!! Only issue I had after throttle body was a hard stutter at high boost and high RPM pulls. Felt like a misfire, but would not register. I put new OE plugs in it and closed the gap down to 26 and it's a beast now. No issues since then.....so hopefully it'll be good through the Winter while I make decisions on going bigger.
-J. Hines

P.S. Check your throttle body and let us know what the part number is. If you have the early one then I'd def. say it's bad. The Audi BT guys are putting a hp number of about 300-350 on our throttle bodies. After that they seem to sh*t out. INA Motorsports has a fix for the issue. If I go through another throttle body I'll be going that route and getting the RS4 throttle body built up.

Thanks! I will pull that sucker off and check the part # just curious how much am I gonna spend on the neww one?

[jhines_06gli]

Thanks! I will pull that sucker off and check the part # just curious how much am I gonna spend on the neww one?

You don't have to pull off, just look on the side with the plastic housing cover. Will 06F 133 062 G or some other letter. Not sure what the guys are getting for price......I work at the dealership, so I get a pretty good deal on parts for my car.
-J. Hines

[chris@revotechnik]

Once again you fail to answer my question.

You have a car that under "standard operating conditions" would show a 0.5% trim.
That car suddenly shows a -3% deviation.According to you, this is "within spec", and
no one should take notice.The following day(s) the car experiences an engine failure
due to a failed injector.The owner comes to you and tells you he is going to sue your ass
cause you told him it was nothing, and within VW spec.Do you honestly believe
you can convince him he couldn't have prevented that by further investigating the
sudden change in the trims ??

your scenario as described is impossible and a change from .5% to -3% would NEVER cause a failure. If you even remotely believe this you clearly do not grasp even the basic concepts of how an engine works. Your car is doing greater than a 4% change while it sits at idle in your driveway, thousands of times a day.

An injector failure would result in 0 fuel, 0 fuel means 0 power in that cylinder and the chance of failure is less than if the car was sitting at idle and running perfectly.

Any injector failure between 0 and normal that would possibly cause an engine failure would cause enough of an imbalance that the car would shut down that cylinder and go into limp mode.

So what exactly is it that you know more than I do on this?

As I has already explained to you a change of that nature is 100% normal and expected in DAILY operation. If someone had an engine failure due to a component failure it would have NOTHING to do with Revo or me and they would have no basis for a lawsuit, apparently another subject I am more well versed on then you are.