Need Help with 2004 passat TDI

QR12 · Aug 15, 2018

Hello, i have a 2004 passat tdi 2.0L BHW that i bought not running. It has 150,000 miles on it and it has been serviced regularly. The previous own said they where driving it one day and it just shut off. I change the ecu and it starts now, but idles very rough, almost like it is missing, and when you put it in gear it stalls. I checked some stuff with VCDS and there are no fault codes. I checked cam timing also and it's at -0.5, which i was told was fine for this engine. Does anybody know what is wrong or what i should check?

Thanks!

oilhammer · Aug 16, 2018

Camshaft maybe?

QR12 · Aug 16, 2018

I don’t think it’s the camshaft because it looks fine and the previous owner said it just stopped running on him while they where driving. It wasn’t a slow decline in performance.

johnboy00 · Aug 16, 2018

Fuel pump or fuel pump relay, perhaps. My fuel pump relay went intermittent and would stall when driving. Is the tank full? Could it be bad fuel? Although I'm not sure how far you would get from a station since the fuel recirculates.

What have you done so far? Changing the ECU seems like a drastic first step, so I presume you've done some troubleshooting. Why did you decide to change the ECU?

DeliveryValve · Aug 16, 2018

Did you check to see if the intake regulating flap is not stuck closed?

QR12 · Aug 16, 2018

When i got the car it wouldn't start and it had a constant code for injection circuit failure. I checked at the injector plugs and wasn't getting any signal to the injectors. I checked the wire loom and it was fine, so i swapped the ecu and i got the car started.

So far i have changed the fuel filter, checked the lift pump - it runs and is making pressure, cleaned the EGR valve, checked the MAF sensor and MAP sensor, and checked cam timing.

VCDS isn't showing any codes for the ecu.

I'm starting to think it could be clogged injectors or maybe a bad tandem pump.

oilhammer · Aug 16, 2018

Look at the smooth idle compensation in the engine data (I forget which group it is, just start at 001 and scroll up). See if anything is way off. A healthy car should have all four values +/- 1.00 or less.

Still, even a dead cylinder won't cause it to die when you put it in drive. But at least checking those values with the engine running may point out one or maybe two cylinders.

QR12 · Aug 16, 2018

oilhammer, i will check that tonight. Thanks

DeliveryValve, i will check that also.

QR12 · Aug 16, 2018

Someone told me to check the fuel return line flow rate to make sure the pump is moving enough fuel. When checks my the fuel that Pumped out of the return I found that it has gasoline mixed with it. So this weekend I’m draining the tank, flushing the lines and changing the fuel filter again. Hopefully that cures my problems.

QR12 · Aug 17, 2018

Got the tank emptied and filled up with diesel, purged the fuel lines and its still running rough and stalling when put in gear.

Checked the intake regulator flap as DeliveryValve said to, its open.

Oilhammer i didn't see an idle compensation, i did see an idle stabilization though. Readings at an idle below.

Injector quantity cylinder 1 2.99 mg/str
Injector quantity cylinder 2 2.99 mg/str
Injector quantity cylinder 3 -3.01 mg/str
Injector quantity cylinder 4 -3.01 mg/str

QR12 · Aug 18, 2018

I pulled the valve cover again to take a closer look at the cam, it doesn't show any wear. I'm getting a compression tester tonight so can do a compression test tomorrow.
https://drive.google.com/file/d/0Bye-Ar8Wpn47TUlEdkYxeFhnVUkwb3AtUmVlTEFzSHlMSnpz/view?usp=sharing
https://drive.google.com/file/d/0Bye-Ar8Wpn47ZkRSRGlWWlEzYjk3RWk1dEdQTmI2aEhZRS1F/view?usp=sharing

QR12 · Aug 19, 2018

Checked compression, all four cylinder were good. Checked wiring, couldn’t find any issues. Going to do a diesel purge on it and see if it gives me any improvements. I’m pretty sure it’s injectors at this point.

Windex · Aug 19, 2018

Very rarely will injectors "just shut off" a car.

Long slow decline, gum up after a period of sitting - absolutely.

When you can get it running, is it running on all cylinders?

PickleRick · Aug 19, 2018

One way to find out for sure. How hard is it to swap the 2 good cylinder injectors for the bad?

QR12 · Aug 19, 2018

It’s seems to be running on all four, 1&2 are just not making any power. The ECU is not detecting a misfire either. I ran diesel purge thru it and it will barely idle in drive now, which it wouldn’t before.

Windex I bought the car about a month ago not running, so it could have had a decline of power that I don’t know about. The guys wife was driving it and he said it died while driving, I found that she had filled it with gasoline and I drained the tank, purges the lines, and put a new filter on it.

oilhammer · Aug 20, 2018

Looks like you have two dead cylinders to me.

You need to determine why.

Compression

Injectors

Valvetrain

QR12 · Aug 20, 2018

Oilhammer, i believe its injectors. When i had the valve cover off there wasn't any noticeable wear on the cam or lifters. I also did a compression test and all for cylinder came back within about 10-15 psi of each other. I was going to see about swapping
two of the injectors and see if it swaps the idle stabilization numbers in VCDS.

nitec · Aug 20, 2018

maybe try to "fix" the harness first? I have gone through a few cars that would "lose" injector 1 intermittently and it was just a loose plug at the end of the harness under the valve cover...taking the injectors out can lead to a few pain in the butt issues...although the harness usually throws a code for injectors

QR12 · Aug 20, 2018

nitec, Like i stated earlier, i am getting pulse to all injectors and one of the first things i did was crimp the injector plugs tight to make sure they were making connection.

QR12 · Aug 20, 2018

Previous injector stabilization reading

Injector quantity cylinder 1 2.99 mg/str
Injector quantity cylinder 2 2.99 mg/str
Injector quantity cylinder 3 -3.01 mg/str
Injector quantity cylinder 4 -3.01 mg/str

Swapped injector 2 & 3 and took a new reading.

Injector quantity cylinder 1 2.99 mg/str
Injector quantity cylinder 2 -3.01 mg/str
Injector quantity cylinder 3 2.99 mg/str
Injector quantity cylinder 4 -3.01 mg/str

peiphil · Aug 20, 2018

QR12 said:
Previous injector stabilization reading

Injector quantity cylinder 1 2.99 mg/str
Injector quantity cylinder 2 2.99 mg/str
Injector quantity cylinder 3 -3.01 mg/str
Injector quantity cylinder 4 -3.01 mg/str

Swapped injector 2 & 3 and took a new reading.

Injector quantity cylinder 1 2.99 mg/str
Injector quantity cylinder 2 -3.01 mg/str
Injector quantity cylinder 3 2.99 mg/str
Injector quantity cylinder 4 -3.01 mg/str

Ya the gas has no lubrication in it like diesel has and 2 of your injectors have seized up as a result !

QR12 · Aug 26, 2018

Put a new set of injectors in and it’s running great.

Windex · Aug 26, 2018

Where'd you source the injectors?

QR12 · Aug 27, 2018

Windex said:
Where'd you source the injectors?

I got them from cascadegerman.com

Need Help with 2004 passat TDI

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