VR6 Electrical nightmare. Internet high fives to anyone with a good idea...

[Einkaufswagen]

So it has been about 3 weeks of me troubleshooting a what i think... is a electrical problem.

Basically i have a VR 12V built from the ground up all new sensors none less than a year old. I took the engine out to do a 6Speed swap which went flawlessly. and after the swap the car ran strong as usual for about 2 days... then the fun started.

Problem day 1: Car stalled once coming to a coast with the foot off the gas light breaking, started right back up.

Problem day 2: again the car stalled when i came to a stop at a stop sign hesitates to start. at this point i start to diagnose the problem.

After day 2 car always stalls when foot is off the gas, shes running pig ass rich sometimes starts but most of the time runs like it is out of time. If I can get it started the car will run fine at 2k+ rpm but again once i take my foot off the gas it dies or barely idles and stalls out.

*** Sometimes the car will idle fine but the car will stall... when i shut the hood...

Things i have tried already / checked.

here is the best part... Vag-Com throws little to no codes after i cleared it. NO codes persist...



Things i have checked / replaced already...

-New Forward 02 sensor
-Swapped in a known working MAF
-Swapped in a known working Throttle Body
-Swapped in a known working Speed Sensor
-Swapped in a known working Hall Sensor

-Checked all the wiring for the Speed Sensor/Hall sensor everything checked out good grounds and no shorting.

-Cleaned all engine grounds and inspected for damage.

-Checked battery and alternator output 13v when not running and over 14v when its running.



My best guess (which has been **** so far...) is that it seems to be temperature / electric related sometimes in the morning it will start right up run fine for a minute or 2 then start to run like A$$.

I am totally stumped and any and all help is appreciated.


Pics for clicks...


Here is the POS all riped up as of today trying to troubleshoot wiring...

[max302]

Same this was happening to me, it mysteriously went away after I messed around with the ESS and reworked a bit of the harness.

Have you tried another fuel pump relay? Wouldn't explain why you're running so rich, but could definitely be the cause of your random shutdown issues.

[vwmaniac16vr6]

what is the coolant temp reading thru vag com, also same for the intake air temp. i am refering to numbers in the measuring blocks. check what your g/s your maf is reading. all the numbers could tell you if those sensors are reading properly.

[GTIVRon]

what is the coolant temp reading thru vag com.

That.

[Einkaufswagen]

what is the coolant temp reading thru vag com, also same for the intake air temp. i am refering to numbers in the measuring blocks. check what your g/s your maf is reading. all the numbers could tell you if those sensors are reading properly.

I will check this next for sure! Once the rain gives up hopefully I can grab all of the codes / measurements.

It did randomly throw a Speed sensor open circut... like one time which is why I replaced the sensor and checked the harnes for a short but i dident find anything? Once I cleared the code it also never came back, so i assume it threw it because of how rough the engine was running??

Another thought is that Ground circut 220 (sensor ground for the Hall sensor and the Speed sensor) is getting powered by a short, possibly causing the sensors to go balistic?

Nothing that I can think of realy explains why the car stalled when I shut the hood lol...


Thanks for the input all. I will let you know what happens.

[prplvr6]

I had similar issues with my 98 GTI VR, and it was the FPR. It would run rich sometimes, then lean, then shut down randomly

[Einkaufswagen]

That is interisting....

I did rerout the vac line going to the FPR right before this happened and I dident think any thing of it.

Does anyone know what the vacume line going to the FPR actualy does? the car runs the same with or without it hooked up...

Here is a diagram of my simple vac setup.



There is no vac ball in the setup and all of the secondary air and obviously the shift rod is gone.

[prplvr6]

Maybe the FPR is stuck "wide open", which would explain why it doesn't change with the vacuum line off. That would also explain it running rich. Thoughts?

[GTIVRon]

Get a fuel pressure gauge. While at idle you should be around 55-60 PSI, as you jab the throttle it shouldn't fall much, then raise back to 55-60 PSI (or whatever pressure it's supposed to if you changed it to 4 bar). The FPR does exactly what it's name suggests, it regulates fuel pressure. There is a spring opposing the vacuum line, as vacuum is achieved it sucks the diaphragm down, as vacuum gets less the spring pushes it back up.

[Einkaufswagen]

Get a fuel pressure gauge. While at idle you should be around 55-60 PSI, as you jab the throttle it shouldn't fall much, then raise back to 55-60 PSI (or whatever pressure it's supposed to if you changed it to 4 bar). The FPR does exactly what it's name suggests, it regulates fuel pressure. There is a spring opposing the vacuum line, as vacuum is achieved it sucks the diaphragm down, as vacuum gets less the spring pushes it back up.

Alright today after work I am going to have a brand spanking new version of vag com, I will try to log engine temps from the sensors.

I am also going to spend most of the time checking the vacuum lines and testing the FPR I have a running vr6 parts car so its just a matter of the old swaparoo to test if somthing is good or bad...

Thanks all

[Einkaufswagen]

Alright so after much battling today with the car still no luck. I am making a video so i can better explain the symptoms.

Also VAG-COM logs shortly.

Today so far

-Repaced the FPR
-No change
-Ground tested the left side of the harness
-No faults found? Everything seemed normal nothing grounded that shouldent be...
- Performed a Throttle body alignment
-No Change
-Physicly checked the vac Lines and system
-No visible damage or noticeable leaks.


I also logged the car from dead cold start until it died
So you can see exactly what all of the sensors are doing.

The car today started diffrently than any other day. It started up ran a little crappy, so i kept my foot on the throttle for about 1 minute. then droped the rpm slowly.

the car Idled on its own at about 1200 and held it there for about 3-4 minuts. and sounded like it was running ok...

It then proceeded to drop idle down to normal range 700-800 or so and started to run like piss and stall out.

[98GTI_VR6]

replace your plugs
and replace manifold gaskets just to check things off the list...
replace fuel filter

also my car runs like **** with the ac on if i forget to flip my fan switch
any chance your ac is on and the fans are not...

[Einkaufswagen]

replace your plugs
and replace manifold gaskets just to check things off the list...
replace fuel filter

also my car runs like **** with the ac on if i forget to flip my fan switch
any chance your ac is on and the fans are not...

-Fuel filter is about a year old. replaced it not to long ago.
-The car has no AC
-I am not sure if the gasket would be a problem? The car runs sometimes and will idle fine when its cooler but once it warms up it starts to act all crappy.

If there was a vac leak at the manifold wouldent it run like crap all the time? Im not sure... il look into that one.

[Einkaufswagen]

Here is the video of the car (Already warmed up) The longer i let it sit the better it will run initially. But once it starts acting up it wont turn over easily if at all.

* when it is running its reving high because my foot is on the throttle if i take my foot off it stalls or runs like piss.

[Einkaufswagen]

And here are some logs

The first one is from Dead cold hasent turned on in weeks start. the second 2 are back to back once the problem starts.










And Vag-Com Block 08 (Engine) throws no codes...

****s driving me nuts!

[Einkaufswagen]

also if anyone is interested

I will gladly paypall anyone 50$ who can spot the problem and provide a solution.

[98GTI_VR6]

coil pack may be suspect
cam angle sensor aswell

[Einkaufswagen]

coil pack may be suspect
cam angle sensor aswell

The cam sensor is out of a car that was running fine to test that.
-No change

I will replace the coil pack and see if it makes any difference. I have 3 spares lol all tested and working.

[vwmaniac16vr6]

your mass air flow numbers dont look right, im going to go scan my car now and see what it reads at idle

[vwmaniac16vr6]

yeah my mas ari numbers are lower all across the board at 1200-1400 im at 8.x no where close to that 12.x reading your getting, your intake aair temp is also low (that is one with the maf) it should normally be 10-15 degrees off your coolant temp when standing, usually when driving its lower. im voting your MAF is bad or dirty.

[acee_dub]

I think if it was the coilpack you would shoot misfire codes like crazy. Check your FPR

[Einkaufswagen]

Hrmm well I swapped that MAF in from a perfectly running car. so i am not sure... I will test the resistances and test the wiring harness.

Your right about the coil pack but at this point anything is possible i think haha. I will replace it anyways.

[Einkaufswagen]

-Replaced FPR
-No change
-Checked MAF for correct resistance at 27C (81F) It reads correct resistance.
-No change
-The FPR Vac line is about a foot long give or take 1 line with no T's directly from the manifold as shown above.

[98GTI_VR6]

just wondering have you done a compression test....
what happened when you replaced the coilpack...and is it possible for the crank sensor to act like **** once you warm up....?

[Einkaufswagen]

just wondering have you done a compression test....
what happened when you replaced the coilpack...and is it possible for the crank sensor to act like **** once you warm up....?

Yeah the engine has great compression.

The crank sensor came out of my running doner car so I know it was working at least before i put it into the problem car.

After I changed the coil pack yesterday I had no change in the original problem. Still started idled for a bit and stalled out, So no luck there...

However afterwards I started unplugging and testing harness conections and replugging, Sensor resistances... etc etc starting essentialy at square 1 and...

The car magicly fixed itself...

This is bad for a few reasons.
-1 I dont know what the problem was
-2 I dont know if it is truely fixed

-I am going to try to log some more normal operating numbers off of the primary sensors and see if anything looks off.

I drove the car around for a few hours around my house and it only stalled once but it was completly diffrent than the original problem. I was going about 30-40 and it seemed like it lost electrical timing with the engine.

It was flashing the EPC and once i pulled over it started right back up again...

I am hopeing that the EPC light threw a more obvious code, but i have been unable to check the codes since.

Since then i have loged about 20 miles of normal-hard driving and no more messup? Asside from it running a wee bit rich.

I will let you all know what i find, I know a few of you are having similar problems...

[GTIVRon]

What does the first O2 sensor wiring look like? Those lambda numbers are going crazy, and moving damn far from 1.0 rapidly. Same thing with "CAT temps." With it running fine now, see if the CEL comes on after a few miles.

[98GTI_VR6]

yea i had my working crank sensor go bad just from unplugging it and plugging it back in when i did my clutch i put it all back together and the crank sensor just took a crap, put a new one on and fired right up....
just sayin vw parts are wierd one day they work the next they dont.
but yea i agree with vron check for codes now

[Einkaufswagen]

yea i had my working crank sensor go bad just from unplugging it and plugging it back in when i did my clutch i put it all back together and the crank sensor just took a crap, put a new one on and fired right up....
just sayin vw parts are wierd one day they work the next they dont.
but yea i agree with vron check for codes now

Yep defonaly once i get home from work i will pull the codes and see if anything new comes up. Its odd that you said it happened after you messed with the tranny. I just finished a 6 speed swap and then all this crap happened lol.

[Einkaufswagen]

What does the first O2 sensor wiring look like? Those lambda numbers are going crazy, and moving damn far from 1.0 rapidly. Same thing with "CAT temps." With it running fine now, see if the CEL comes on after a few miles.

The pre cat is brand spanky new. right out of the box that was the first sensor i replaced because the previous engie in this car did the same exact thing and the precat 02 was the cause.

It like some sort of VR6 Ebola Virus lol.

[Einkaufswagen]

So drove the car to work this morning and she dident skip a beat.

The car sat in the parking lot for 8 hours.

Go to start it to go home and right back to square 1. Shes running like it was before starts misfiring backfiring very low idle and super rich...

Back to the drawing board i guess...

I have no idea what the hell can go wrong on a car that sits for 8 hours...

[Einkaufswagen]

New Rear 02 come sin today I also plan on resistance checking all of the 02 wires because they have neen rerouted (Cut and resoldered) Everything was done professionaly but its a possibility that the solder has messed up the resistance of the wire.

Luckly i have a perfectly good harness to check agenst, I will let you all know...

[Einkaufswagen]

So heres a late update mainly because i needed to take a break from this thing...

I ended up swaping the built engine into a clean OEM body with basicly completly a completly new electrical system. I figured this was the most extreem way to correct what i thought was a electrical problem...

Well it turns out its not electrical because the lemon started up ran for about 1 minute and died... Total buzz kill.

On the bright side I ruled out the entire electrical system Harness, ECU, sensors, and coil packs and everything in between is new...

I have checked spark check the fuel injectors to make sure there all fireing at least and everythingis working it seems.

My last stab at this before i tear out the built engine and throw in a OEM is that for some reason it skipped a tooth? or possibly I lost compression in a few cylinders...?those are the only two mechanical problems i can think that would cause a bad idle / misfire...

If anyone has experianced any mechanical problems that cause a vr to start and sputter out please god feel free to enlighten me. I am truely sick of this thing and just want it to work

[R32Smoker]

That sucks man, I feel your pain! My VRT has been doing something very similar for the past 3 months; It will start up fine, run great for about 25 seconds, than dies out. I'm getting a system too rich error code. I changed out my entire ignition system, various sensors, and put in a new wiring harness and ECU (I have been blowing out ECUs for some reason), but my car still won't run right.

My car seems to be flooding out with too much gas, I'm checking out my injectors next. Is your car also flooding out your spark plugs?

[Einkaufswagen]

That sucks man, I feel your pain! My VRT has been doing something very similar for the past 3 months; It will start up fine, run great for about 25 seconds, than dies out. I'm getting a system too rich error code. I changed out my entire ignition system, various sensors, and put in a new wiring harness and ECU (I have been blowing out ECUs for some reason), but my car still won't run right.

My car seems to be flooding out with too much gas, I'm checking out my injectors next. Is your car also flooding out your spark plugs?

If I check my plugs about 4 of them are flooded and the other 2 will be fine.

After spending a few hours yesterday refining my search on what the causes are I came back to the idea that it’s the Engine Speed Sensor

People that have had EXACTLY the same problem as me have fixed it by replacing the speed sensor.
-Car started stalling at stoplights and low idles when problem first started
-Car progressively got worse to the point where it wouldn’t stay running
-Car starts and runs for short periods of time but then stalls
-Car randomly works sometimes but the problem comes back
-Car sometimes throws Engine Speed Sensor (G28)- Implausible Signal – Intermittent (If it runs long enough)

Now i already replaced mine with a good used sensor out of a running VR but just to be safe i ordered a brand new one and i plan on pulling the oil pan to inspect the timing gear that the speed sensor reads off of. I have read in some rare cases of metallic debris getting wedged in the fear and causing all sorts of hell.

At the same time while the sump is off I am going to check the gap between the sensor and the timing gear. My probrem started after i had the engine out to do a 02M Swap so it is possible while the engine was being tipped or rocked around that shavings got stuck in the gear? Because I just shoved the used sensor in without cleaning the mating surface of the sensor to the block it is possible that the gap is wrong between the sensor and the timing gear.

I will keep everyone up to date on what I find when I’m in there and I will probably snap a few pictures in case I miss something.

I really want to fix this problem so no one has to go through this hell like I am ha-ha. I wouldn’t wish this problem on my worst enemy

[Einkaufswagen]

Engine speed sensor comes in today. Is there anything i should know and be carefull about when installing?