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Discussion Starter · #1 ·
Friday was a bad car day. Both cars quit on the same day! One of them was a radiator that sprung a leak, and I finished fixing that on Saturday morning, so it wasn't that bad. But the Passat is giving me headaches.

2003 Passat GLS 1.8T, 140k miles. Ran fine up until that day. My wife drove to work (15 minutes), ran fine. Headed across town on the highway mid-morning, and acceleration was poor, started to run really rough, vibration. Got off highway and stopped and noticed smoke. So I drove across town and brought her the other car. At this point, when I looked at the Passat, it wouldn't start at all, cranked fine but no firing at all. Had it towed home.

Coolant level was down by about a pint after it stopped. I think it had been full just before but not certain.

Later at home, suspected fuel pump for not starting at all, wondered if the low power had been from failing pump. In the process of debugging the fuel pump, while I had the fuel supply line removed and pointed into a bucket, the engine decided to start, just barely, with whatever fuel was still in it. So I put the line back together and started the engine. It runs terribly rough, and blows profuse amounts of smelly smoke.

The smoke doesn't look particularly "blue" to me, but it seems like oil, due to the strong smell and also since after I shut it off, wisps of smoke continued to come for minutes from the tailpipe and the flex pipe under the front middle of the car (so now I know where the exhaust leak is).

It seems like it should be obvious what went wrong, but I can't pin anything down.

Codes from a simple scan tool didn't tell me much:
P0171 lean
P0300, 301, 302, 303, 304: misfiring on all cylinders. I could tell that.
P0139 O2 sensor, P0420 catalyst efficiency: It normally gives me these codes. I gave up on trying to solve those a while ago after replacing many parts.

The compression is 135psi +/- 5psi on all 4 cylinders. Nothing notable to see inside the cylinders with a scope.
Intake seems relatively clean. A little bit of oil in the hose from the intercooler to the throttle where it normally is. The hose from the airbox to the turbo is clean.

I was thinking the turbo was seized up. Got the intake hose off. The rotor spins freely, a little side-to-side play and just enough end-to-end play to feel it but not much at all. So not seized.

Took out the O2 sensor. Looks like oil in the exhaust manifold, scraped a Q-tip of it. Looked inside with a scope and the exhaust side of the turbo looked shiny, like maybe a sheen of oil, but not really sure.

Oil level is normal.

Could it be that the turbo oil seal is gone and it is spewing oil into the exhaust? If so, how can I confirm this while taking the least amount of stuff off?

It looks like there is a seepage of oil from the seam between the exhaust manifold and the turbo. If oil was coming from the turbo, why would it go up to come out here? Does that mean the source is further upstream?

If it's just dumping oil into the exhaust, it would smoke, but why would it run rough?

How else would oil get into the exhaust or into the cylinders?

Could burning coolant cause these symptoms? Can it smell that bad? If so, from turbo? Or where? Head gasket? I thought that typically drove combustion gases into the coolant, not the reverse? And wouldn't I then see moisture in the cylinders?

Thanks for any ideas or relevant experiences! I'm stuck.
 

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It could be as simple as a vacuum leak. Take a look at the "infamous L-hose"--mine split on the bottom (where you can't see it) and the car would barely run. (That's the new one in the picture.) There are plenty of other places for a vacuum leak on this engine, of course, and vacuum leaks seldom cause any "helpful" codes.

103976


The picture below shows the vacuum hoses (in blue) that would get very hard and needed replaced in the earlier models. They used longer-lasting hoses in later models, but worth checking. (I have a vacuum hose DIY in the info base--the most widely-read piece I've ever written!)

103977
 

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+1 on the vacuum leak. From what I've read, usually a bad turbo will dump oil into the intake hoses. As you said, a little is normal so the turbo is probably OK.

Can you check the fuel trims while the car is running?
How old is the O2 sensor and what is its condition?
 

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P0300, 301, 302, 303, 304: misfiring on all cylinders....The compression is 135psi +/- 5psi on all 4 cylinders. Nothing notable to see inside the cylinders with a scope.
Intake seems relatively clean. A little bit of oil in the hose from the intercooler to the throttle where it normally is. The hose from the airbox to the turbo is clean.
You didn't mention condition of the plugs, so I suppose that means there was nothing unusual when you removed them for the compression test. So if it is smoking, but the plugs don't look shiny from excessive oil, or bleached white from coolant, then I would suspect the turbo. I don't know what would explain the rough running, except that the O2 sensor might be sending a false lean-reading.
 

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A bad turbo will make noise before failing and will smoke like crazy. It would hurt power, but not misfire most of the time. The headgasket will cause a quick drop of the coolant, so unless your tank is suddenly low, I would rule that out too.
 

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Discussion Starter · #7 ·
Good idea to check for vacuum leaks. I didn’t think of that since I’ve never had them with smoke, and usually the effect of those seems to go away just off idle. Maybe a big leak could cause this? Anyway, I have a smoke tester I made for a previous vacuum leak incident on another car, so I’ll try that. (Or if I filled a balloon with the exhaust, that would work ;)

You’re right, the plugs looked great when I took them out. They aren’t too old, 10k miles maybe. I replaced both O2 sensors 2-3 years ago, 30k miles maximum.

The coolant did drop a bit, though maybe it already had been low. So I was thinking maybe a coolant leak into the exhaust from the turbo (if that's possible). But, I put the cooling system under 15psi yesterday for 5-10 minutes, and didn't find any leaks, including into the cylinders or exhaust manifold. Still wondering about oil leaking from the turbo into the exhaust, if it can go that way only but not into the intake. Then that making the O2 sensor confuse the ECM.

I have the VCDS-lite, so maybe I can see the fuel trim? I haven't found my way around that much but I know there is info around here.

I didn't know running with the MAF disconnected was a thing you could do. I'll read up on it and try it.

Should have more time to mess with it this weekend.

Thanks all for the ideas! Will update...
 

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Discussion Starter · #8 ·
I still don't know what's going on, but it's probably staring me in the face. Can anyone help interpret these symptoms?

Running with MAF disconnected was about same.

But as it turns out, there was a vacuum leak. I missed it the first few times. It was in the line that comes off the bottom of the intake manifold, goes to a tee, then each end off to a one-way valve and beyond. The line was completely cracked off of one of the check valves. (Turns out, the tee had broken 2 years ago and I replaced those lines. I used 5/16 Goodyear SAE 30J7 fuel line, date of manufacture 2014, and it cracked in 2 years.)

So I fixed that and put it all together. Started it up and it ran about same. I took off the battery cable for a few hours while I did other things, since on other cars, clearing the ECM has helped it re-learn after fixing a vacuum leak. Still same: running rough, lots of what I would call gray, smelly smoke.

But something is getting worse (which should at least make the problem more obvious).
The seam between the exhaust manifold and the turbo weeps with oil or gas when it's running, like I mentioned above. Seems to be getting faster. And now it's started blowing oil (or possibly gas?) out of the flex pipe which clearly has a leak in it. It put quite a puddle on the driveway. I had a hard time deciding if it was oil or coolant...they both seem to feel similar on my fingers, and the color I figured didn't mean much after going through the exhaust. I dipped a Q-tip in and put a match to it, and it lit up, so I concluded it's oil. (Tried same thing with coolant and oil, and the coolant didn't light, though I understand it can burn if it hits a hot enough surface.) Seems too thick for gasoline, and didn't evaporate quickly. But...

I took out the plugs again and this time they tell a different story (don't know why it changed so fast). Plugs 2-4 are black with light spots, what the Hanes manual calls ash deposits. Plug 1 was moist, the electrode tip looks black, but the insulator seemed yellow-green and shiny. Though in a photo taken later the insulator looks more brown-black and blistered.

I pointed the boroscope into cylinder 1, and the light seemed to reflect off something shiny, like liquid, in the lowest part of the cylinder (it's slanted like an old Dodge). I dipped a Q-tip in and it came out moist and smelling like gas.

I also took off the oil cap while it was running and it had positive pressure pulsing in the crankcase. Not sure how that compares to normal.

So...I'm confused between what seems like oil in the exhaust, which doesn't seem to come from the turbo since it's present at the seam with the manifold, and what seems like a bunch of gas in cylinder 1, but with 2-4 clearly not having a good day either.

Do fuel injectors get stuck open? Would that cause this? I need to locate a fuel pressure gage I suppose.

Could oil be profusely leaking into a cylinder despite the good and even compression readings?

What else?

Thanks again.
 

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Discussion Starter · #10 ·
104036

Mess under car, drips from flex pipe, upside down?!?

104037

The vacuum leak…upside down, sorry!
 

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It could be a stuck open injector, but you usually lose compression with one. A single misfire should result, so once the air leak is repaired, see if it's just a single misfire code. I would expect the dripping liquid to be a mix of condensation, soot, and unburned fuel from the misfires.
 
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... And now it's started blowing oil (or possibly gas?) out of the flex pipe which clearly has a leak in it. It put quite a puddle on the driveway. I had a hard time deciding if it was oil or coolant...they both seem to feel similar on my fingers, and the color I figured didn't mean much after going through the exhaust. I dipped a Q-tip in and put a match to it, and it lit up, so I concluded it's oil. (Tried same thing with coolant and oil, and the coolant didn't light, though I understand it can burn if it hits a hot enough surface.) Seems too thick for gasoline, and didn't evaporate quickly. But...

Do fuel injectors get stuck open? Could oil be profusely leaking into a cylinder despite the good and even compression readings?
Your post is one of those frustrating ones, because you obviously understand how to troubleshoot - and so-far you and the forum hasn't found a conclusion, yet.

I agree with PZ, that the fluid coming out of the flex pipe will be a mix of whatever is in the exhaust system plus combustion condensation. And I think that a "stuck open" injector would mean a non-running cylinder plus an unmistakable fuel smell, so I would discount that. Are you still keeping an eye on the oil, incase there is coolant mixing? Maybe try running for a while with the oil filler cap off, to see if excessive crankcase pressure is the problem, although I doubt that would make the engine stall and not start.
 

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Discussion Starter · #13 ·
I think I confirmed the stuck open injector theory. After the ECM reset, it did indeed only give P0301, cylinder 1 misfire, matching up with the pattern on the plugs. I put a gauge in the fuel line, and it didn't stay up at all, just went right back down after cranking. Then, I got lucky, since cylinder 1 must have stopped in the intake stroke, and I saw through the spark plug hole that fuel was dribbling into it.

So tomorrow I'll obtain some injectors and o-rings. Looked like the o-rings needed changing anyway.

Still can't figure out the sequence of things. Seems odd to have two problems happen at the same time (vacuum leak and stuck open injector), unless one caused another, which I haven't thought of a reason for. Maybe the vacuum leak was there longer, but being a completely open hose, I wouldn't think it would go unnoticed. Also no idea why it decided not to start for a while.

Cylinder 1 still has good compression. I was worried that it was dumping so much fuel that at some point I might have cranked it while a lot of liquid fuel was in there. Seems OK.

Anyway, we'll see what happens next. Relieved for the moment that it might not be bigger than an injector.
 

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Discussion Starter · #14 ·
Oops, just noticed I posted the same photo of plug 1 twice and no photo of 2-4.
104040

Here is plug 4. 2 and 3 looked similar.

(Also, after sitting in the engine for a day not running, they looked much more normal. So maybe that’s why I said they all looked good earlier; I might have waited too long to pull them after running. Good thing to learn.)
 

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Discussion Starter · #15 ·
Oh wow, didn't realize how expensive new injectors are. Was just thinking to replace them all if one did this on me.
Has anyone tried injectors from GB Remanufacturing? Available at FCP Euro. Claim to be remanufactured Bosch injectors.
Or used injectors?
 

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I expect the injector is not stuck fully open, just flowing so poorly (gummed up/clogged, not sealing fully closed) it's not firing well. They can often be cleaned, checked and re-used if you have a good shop nearby. I would buy 4 GB ones from FCP, as they are a good price and shops that do that type of work are hard to find in most areas.
I suspect the injector was slowly getting worse and then the vacuum line caused a more severe problem. With a poor injector, they are much worse on a cold engine, which makes diagnosing them much harder. It's rare they go bad, but contaminants in the fuel can ruin them.
 

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If you can get to a U-pull junkyard, you can pick up some injectors for less than $10 each. Nice to keep a few on hand in case there is ever a question they are an easy swap.
 

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Oh wow, didn't realize how expensive new injectors are. Was just thinking to replace them all if one did this on me.
Has anyone tried injectors from GB Remanufacturing? Available at FCP Euro. Claim to be remanufactured Bosch injectors.
Or used injectors?
Years ago I installed a set of refurbished injectors from an east-coast injector shop, although I don't remember the name. They worked perfectly fine; I do remember that the set of six was about $125 back then.
 
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