Anyone with a cold start misfire...

[GolfRS]

UPDATE:It seems i might have spoken too soon (crosses fingers)
After a run of "italian" tuning, the idle seems a bit better.I do get the
occasional misfire, but not nearly as i used to.Is there any reasoning behind the thought of "getting the effected cylinder cleaned out" before the new injector actually shows it worked ?

What i mean is, is there any possibility the cylinder might be "dirty" from
the bad injector, and things will improve even more ??

Stay tuned...

[GolfRS]

Well..the idle misfires are back again, and in full force....

Waste of time and money replacing the injector (at least i did it myself
and didn't waste even more money on a shop)

Now things are getting trickier, cause a compression test and a leak down
test are in order.Also, i'm probably getting my lifters replaced when
doing the cams.Its just that it simply doesn't feel right installing cams, when the car is running poorly with the stockers on...

Oh and i'm also going back to the factory airbox to see whats up.
Removed the MAF and although i had misfires they were NEGLIGIBLE, and not of the same "intensity"

[JLT]

maybe its your tune

[GolfRS]

Quote, originally posted by JLT »

maybe its your tune

Nah..

I'm only experiencing misfires at IDLE, which means there is some form of "leaking", be it from the
valves, or the rings maybe.Could also be the PCV, but i've checked that and it doesn't seem to
be faulty (its quite possible it has failed internally though, so i'll have to double check.

Misfires have gotten progressively worse over time, but still ZERO at WOT...

I swear this motor is gonna drive me NUTS !!!

[TAIVWAUDITECH]

You are not the only one!I have 2 customers that have this EXACT same issue!!New CP/plugs,etc.,etc.,drives fine,misfires in 1-2 cylinders only at idle,and if you unjplugther MAF,it "cleans up" the mis-fires a bit.........Don't get offended......but I sure am glad I gots a 1.8t!!

[fahrenheit 525]

How many misfires is acceptable? how many or how bad does it need to be before HEY! there's a problem here. just curious

[GolfRS]

Quote, originally posted by TAIVWAUDITECH »

You are not the only one!I have 2 customers that have this EXACT same issue!!New CP/plugs,etc.,etc.,drives fine,misfires in 1-2 cylinders only at idle,and if you unjplugther MAF,it "cleans up" the mis-fires a bit.........Don't get offended......but I sure am glad I gots a 1.8t!!

Hmmm...

So what do you reckon is the diagnosis ??

All the tests turn out normal ? (compression etc)

As for the "how many" part, well for me even one is too many.

Its IDLING FFS !!! If the motor doesn't work properly at its most relaxed, then
what does that say about the health of the car ??

P.S. TAIVWAUDITECH btw do these customers happen to have an AXX motor ?I know
its a European motor code, but i've heard there were a few early A3's that made it to
the U.S. market...


Modified by GolfRS at 7:29 AM 4-28-2009

[20vGinster]

I have the same damn problem! 2006 FSI 85k miles, stock software. It only misfires in cylinder 3 on cold start/high idle. Once the idle drops down the misfires go down to nearly nothing.

Changed the plugs, coil pack, injector, tried running it with the intake flapper unplugged. Same misfires. Temperature or weather outside do not matter. Going to do a compression check on cold start next. My thoughts are it could be a sticky valve on the guide.

Have you tried running Seafoam through the intake manifold?

[20vGinster]

oh another thing.....fuel pressure at idle is around 50 bar....when it sat overnight before I replaced the injectors it bleeds down to around 6 bar and as soon as the car is started it is back up to 50 or so. I have not check the fuel pressure overnight since I swapped the injector (was yesterday). Not sure if that is normal or not. The cam lobe for the HPFP looked fine too.

[GolfRS]

Quote, originally posted by 20vGinster »

I have the same damn problem! 2006 FSI 85k miles, stock software. It only misfires in cylinder 3 on cold start/high idle. Once the idle drops down the misfires go down to nearly nothing. Changed the plugs, coil pack, injector, tried running it with the intake flapper unplugged. Same misfires. Temperature or weather outside do not matter. Going to do a compression check on cold start next. My thoughts are it could be a sticky valve on the guide. Have you tried running Seafoam through the intake manifold?

Seafoam ??? LOLOL...

Man i just spent last weekend replacing an injector BY MYSELF, and also 3 hours of
intake valve cleaning job...BY HAND...

What is Seafoam again... ???

[GolfRS]

Quote, originally posted by 20vGinster »

oh another thing.....fuel pressure at idle is around 50 bar....when it sat overnight before I replaced the injectors it bleeds down to around 6 bar and as soon as the car is started it is back up to 50 or so. I have not check the fuel pressure overnight since I swapped the injector (was yesterday). Not sure if that is normal or not. The cam lobe for the HPFP looked fine too.

Fuel pressure drop is normal when the engine is not working.

Nothing to worry about....


Modified by GolfRS at 12:40 AM 5-9-2009

[acascianelli]

I'm having this exact same problem with my 1.8T Beetle. I have APR Stage1 on the car right now, and switching back to stock helped it alot but it's still misfiring on cold startups before the secondary air kicks in.

I've tried...
new plugs
new coils
swapping plugs
swapping coils
new fuel filter
cleaning mass air sensor
new mass air sensor
cleaning throttle body
new coolant temperature sensor
...all with no success.

I'm going to try running a can of seafoam through the intake manifold and see if that helps.

[Murder'd]

A misfire is probably occuring due to the decrease in the ability of the tumblers to do their job probably from sludge build-up or the valves being so caked with sludge that they are severely restricting flow.

What is the mileage of everyone with a misfire that has replaced everything and when was the last time you seafoamed or had your valves cleaned?

[saaber2]

Are u guys who are having these misfire issues running stock pcv setup? Just wondering if anyone who is running catch cans or pcv bypass systems are having these problems.

It seems to me that getting rid of the pcv derived gunk/sludge/carbon/deposits is priority #1 for this engine.

[acascianelli]

No catch can
~76000 miles
Running Mobil1 since ~40000 miles.

[Murder'd]

Guy A has problem X at 76000mi w/ stock PCV
Guy B has problem X at 85000mi w/ stock PCV

Not a bad start to proving my theory.

Edit: GolfRS did "clean" his valves when he changed injectors and still had the same problem so maybe that's not it.


Modified by Murder'd at 3:44 PM 5-19-2009

[acascianelli]

Where is the PCV valve located? How hard is it to replace?

[GolfRS]

Quote, originally posted by Murder’d »

Guy A has problem X at 76000mi w/ stock PCV Guy B has problem X at 85000mi w/ stock PCV Not a bad start to proving my theory. Edit: GolfRS did "clean" his valves when he changed injectors and still had the same problem so maybe that's not it. Modified by Murder'd at 3:44 PM 5-19-2009

Yeah, thats true...And to add to the above, people may thing valve deposits are some
sort of a TFSI Demon, but other than some slight feeling of the engine being "more free",
there was ZERO effect on performance.And trust me i had A LOT of carbon fouling in there.

I'm gonna go through and eliminate all the known causes for my ****ty idle (PCV, other leaks, MAF
sizing), and then i'm probably gonna end up installing new injectors.....

[iGen3]

Quote, originally posted by GolfRS »

Yeah, thats true...And to add to the above, people may thing valve deposits are some sort of a TFSI Demon, but other than some slight feeling of the engine being "more free", there was ZERO effect on performance.And trust me i had A LOT of carbon fouling in there. I'm gonna go through and eliminate all the known causes for my ****ty idle (PCV, other leaks, MAF sizing), and then i'm probably gonna end up installing new injectors.....

got my injectors sitting here in a box, waiting for me to decide to do 'em. Not sure that's how I want to spend Mem. Day weekend tho...

[GolfRS]

Quote, originally posted by iGen3 »

got my injectors sitting here in a box, waiting for me to decide to do 'em. Not sure that's how I want to spend Mem. Day weekend tho...

Are you doing a swap cause of misfires ?
Or part of a new setup ?

Or maybe thinking of selling them ?

[saaber2]

Quote, originally posted by acascianelli »

Where is the PCV valve located? How hard is it to replace?

It is not just a failing PCV that is the problem. A normally functioning stock pcv system is also the source of the nasty deposits seen by so many (see referenced thread for an example photo) and as stated by VW in the patent, the source of misfire problems.

Since this pcv-derived gunk can affect so many things, improper airflow, incomplete combustion, misfiring, promoting fuel dilution, fuel injector deposits, valve deposits, who knows what else (tumbler clogging?), (sludge promotion?), other??? It seems to me getting rid of this source of gunk is crucial. If it can't be eliminated completely through a bypass system, at least a catch can should be used along with seafoaming and fuel injector cleaner use in the gas. All IMO.

From my thread here:

http://forums.vwvortex.com/zerothread?id=4387972

VW themselves, in the patent for this engine, say that eliminating the PCV would solve the deposit problems but they can’t due to emissions:

"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components.

...the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result.

...Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures.

...These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle."

"A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible. "

- Thanks to Rl_RS4 for finding this patent info. Check out his thread listed at bottom of this post for more info.

...Quote, originally posted by A3_yuppie »
Which patent are you getting the quoted passages from?
http://www.google.com/patents?...A1,M1

This was found by RL_RS4

Modified by saaber2 at 3:18 PM 5-19-2009


Modified by saaber2 at 3:24 PM 5-19-2009

[iGen3]

Quote, originally posted by GolfRS »

Are you doing a swap cause of misfires ? Or part of a new setup ? Or maybe thinking of selling them ?

Mad Misfires (near continuous at idle) on cyl #4. figured I"d clean the valves and toss 'em all in there while I have it all apart. Stock all. 97K miles at this point. got the "D" DV also, that'll go in also. ....But I have to set up the blue ring pool first for the kiddies..I have 5 and they rate over any of this VAG stuff.

[GolfRS]

Quote, originally posted by iGen3 »

Mad Misfires (near continuous at idle) on cyl #4. figured I"d clean the valves and toss 'em all in there while I have it all apart. Stock all. 97K miles at this point. got the "D" DV also, that'll go in also. ....But I have to set up the blue ring pool first for the kiddies..I have 5 and they rate over any of this VAG stuff.

Hmmmm....

Yeah...I would first do a "coil swap" test to see if the misfire follows,
but i'm guessing of you don't have any at WOT, coils are ok.

If you do decide to swap them, my advice (now after all my trouble) would be to change
ALL OF THEM.That's so you don't have to worry about the injectors again IF you continue misfiring
on other cylinders also.

[iGen3]

Quote, originally posted by GolfRS »

Hmmmm.... Yeah...I would first do a "coil swap" test to see if the misfire follows, but i'm guessing of you don't have any at WOT, coils are ok. If you do decide to swap them, my advice (now after all my trouble) would be to change ALL OF THEM.That's so you don't have to worry about the injectors again IF you continue misfiring on other cylinders also.

been playing musical coils for too long...yes, this is why I have 4 injectors in the box. I'm not doing this again til 150k miles....don't have time for this baloney.

[pal]

I am surprised no aftermarket place has come up with a catch can setup for the PCV. FWIW, when I was running a supercharger on my GTI VR6 a few years ago, I used a Campbell Hausfeld inline air filter on the PCV hose. This did an OK job of filtering out oil from crankcase blowby; however since the bottle was so small, it needed cleaning out every week- not hard, but a PITA for a lazy b*tt like me.

An Amazon link to it - http://www.amazon.com/Campbell...OAFGO

Ideally, on the 2.0T, there seems to be enough space on the front DS of the motor for a PCV catch can from Greddy or Summit Racing so nothing goes into the motor.

[dmorrow]

I don't know if this relates at all to what you are experiencing but I had a bad cold start misfire a couple of months ago. The odd thing was it would come back even when the car was warm if I drove behind a big truck that was kicking up snow or if it started snowing hard.

I took it in and they replaced the Low Pressure Fuel Sensor and it didn't help at all, then they replaced the Coolant Temperature Sensor and it did nothing to help the issue. The final thing was they replaced the Intake Air Temperature Sensor and this solved the issue. I was at about 73k miles, I paid for the first two sensors and they paid for the last one.

[acascianelli]

edit...nevermind

[saaber2]

Quote, originally posted by pal »

I am surprised no aftermarket place has come up with a catch can setup for the PCV.

Try BSH or FFE or run road tube (vent to atmosphere) without a catch can ($25 DIY) or atmospheric with catch can or run bypass to exhaust

[rippie74]

me too slight misfires, nothing big though

[saaber2]

Quote, originally posted by rippie74 »

me too slight misfires, nothing big though

I wonder if seafoaming the valves and lubro-moly fuel injector cleaner in the gas (I'm impressed with this stuff for under $6) would clean it out enough to stop minor misfires?

[rippie74]

Quote, originally posted by saaber2 »

I wonder if seafoaming the valves and lubro-moly fuel injector cleaner in the gas (I'm impressed with this stuff for under $6) would clean it out enough to stop minor misfires?

I'll get maybe 1 or 2 @ 1st start up & that's it...

[rbradleymedmd]

Golf, I know the few times I have come across a soft code for misfire @ idle was due to my intake flaps not reaching the full range of motion. By chance, have your run the readaptation for the flap motor since your issues (I'm guessing you have, just curious as it always seems to solve my issues whenever I run into an idle-misfire issue)?

[GolfRS]

Quote, originally posted by rbradleymedmd »

Golf, I know the few times I have come across a soft code for misfire @ idle was due to my intake flaps not reaching the full range of motion. By chance, have your run the readaptation for the flap motor since your issues (I'm guessing you have, just curious as it always seems to solve my issues whenever I run into an idle-misfire issue)?

Actually its funny you should ask that cause its something i was thinking of asking about
in the forum.

I do adaptations to both my TB and the flaps, but what seems pretty
weird to me is that on block 142 in adaptation,
i can just see the lowest setting and the highest setting appears as zero...
After adapting, it locks on the highest setting as well (around 3. something)
but after turning the key on and of again, the setting is again ZEROED...

So i really don't know if that is normal..

Also, i've done EXTENSIVE logging at idle, and what i've been able
to see is that there is really BIG fluctuations in lambda values
with the car running on idle, ranging from 0.95 to 1.12 !!
Also, my MAF values get f*cked up at times, reading from as low as 1.8 g/s
to 3.5 g/s

One last thing i find really peculiar is that my vacuum value and
my MAF values, fluctuated when i press the clutch pedal !!!
Thats when i also get most of the misfires.
Is there ANY connection between the clutch pedal and the cars idle ??
Really weird stuff...

[jackmup]

I have this problem on a 3.0

Cyl 4 misfires 20 times on cold start and 1 misfire from any one of the other cylinders that changes.
then stops, Vag Com clears and car will run fime for the rest of the day unless it gets cold again.Cold I mean below 70

Funny it went away for ten days and CEL went out on it's own.

the only thing different about those ten days was two things
1) the low temp here in Florida did not drop below 70 degrees
2) It did not rain and I did not wash it.

I realy think it has more to do with a sensor /computer misinterprtation.

I got it to misfire warm by enriching the startup mixture so thats got me thinking it's computer related.

OPEN LOOP PROGRAMMING- Preset parameters used in cold operation. Once coolant temperature reaches a set temperature the vehicle enters CLOSED LOOP PROGRAMMING in which it adjusts to reality.

The problem does not follow, coils, plugs or injectors.
It lasts 20 seconds at best.
Sea foam had no effect. but if theres alot of carbon it wouldn't

I am still testing mine (everything I can imagine or read about)
I thought you might like to read this

TSB 01-04-06 Update For an Audi 2.7t

Programming (Flashing) Engine Control Module (ECM) to Correct Cold Start Engine Stumble (Aug. 30,2004)

After Cold Start Engine Runs Rough. Vehicle may Stumble, Buck and or Shutter on initial acceleration. Engine may stall at idle when transmission is shifted from Neutral/Park to Drive/Reverse.

Condition usually lasts for less than 30 seconds after engine start. Afterwards the vehicle starts and runs without any complaints.

Condition associated with the following DTCs.
P0300 Random/Multiple Cylinder Misfire Detected
P0301-P0306 Cylinder 1 through 6 Misfire Detected

That was sudgested to me by an Audi tech on-line BTW

Audi so far won't just flash the ecm for me, I guess they want a piece of the Diag Pie. But that's not going to happen. So I'll have to just do all the diag myself and right it down for them. I'm not paying for them to determine that my new coils and plugs are ok etc,etc...

I do like the temp sensor idea because the problem goes away at higher temps. I'll try to trick it with a hair dryer and see what happens.

Modified by jackmup at 5:42 AM 5-22-2009


Modified by jackmup at 6:03 AM 5-22-2009

[jackmup]

well this is what I have come up with.

Cylinder 4 valves are most likely clogged up with carbon causing a decrease in compression. Not seating correctly.

Below the 70 degree threshold the ecm operates in open loop and dumps extra fuel into the cylinders and retards the timing as far as possible on a cold start.
After you have run a while and shut the engine off the engine heat keeps the air inside the chamber warm for quite some time so it will restart in closed loop because it registers it a s being greater than 70 degrees.

I don't think the cylinder is capible of igniting all of this extra fuel with the compression loss and retarded timing.

So this is what I did.

I put two bags of ice on my MAF/IAT sensor to trick it into thinking it was cold out (otherwise I have to wait until tommorow morning) I used the unisetting program or lemmiwinks would work and I turned the startup fuel enrichment to 10% then it misfired 5 times. So I turned it to 0% and the misfires stopped.

so that will help me for now or really for ever because 68 is low low in Florida.

I am going to now pull the injectors, Turn Cyl 4 to intake valves closed and pour seafoam down the injector hole and let it soak. I then will attemp to stick a long thin round gun cleaning brush down there and scub what ever I can. Then suck as much crap out the spark plug hole as possible.

If that doesn't do it I'm going to leave it be for a month and see if it improves and basically contimplate if I feel like pulling my heads or my pudd durring my July Vacation. maybe it will loosen it enough. I fear if I don't address it now it will only get worse.

What really needs to be done here is to pull the heads brush the valves and lap them back into the seats. (I just did the T-B too)

I'll let you know how I make out with the sea foam.


Modified by jackmup at 10:25 AM 5-22-2009