B4 suddenly running rough, weird injector balance

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
So W386 borrowed by B4 and drove 3 hours to pick something up for me, then drove home. He never shut the car off. It's now very lumpy and runs rough. It starts mostly ok when I started it yo grab this screenshot. It ran the same when warm with the same group 13. The IQ was lower (it's cold in the below photo) and the dynamic timing is within spec.

Ideas? Possibly a bad #3 injector? It's always run great. The injectors were setup by DBW 7 or 8 years ago and have around 120k on them. They were always +-0.5.

 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
I'm suspecting a pump problem. Doesn't #3 just deal with timing and the crank speed sensor handles crank speed from which balance is figured?
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
I’d toss a spare #3 in there, to test. Those nozzles should have a free calibration service with them. May be a good idea to use it, if it ends up being an issue with #3.

-Todd
 

greenskeeper

Top Post Dawg
Joined
Mar 10, 2003
Location
USA
TDI
1998 Jetta TDI
My 98 ran like that when the "thermostatic tee" at the fuel filter was sucking a tiny bit of air into the pump.

I eliminated that T by splicing the return line together and using a filter from an 86 IDI

could also be bad or partially gelled fuel (given the extreme temperatures), a bottle of diesel911 would be a easy fix.
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
Not gelled fuel since it ran for hours without an issue and I heavily treat my fuel.

Not the thermostatic T since there were no air bubbles in the fuel lines.

Now that it's above 0° I'm going to check the resistance on the #3 and do more poking around. W386 is due over to help and also toss the wagon back together.
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
Sometimes finding what it's not is half the battle, and after some diagnosis today, I still don't know the problem but I know what it is not.

It's been brutally cold here and yesterday with the salamander running I was able to get the inside of the unheated garage to about 20 degrees. Today I broke out the construction heater as well and with 140,000 BTU's of propane was able to get it to 40 degrees inside. That's as warm as it would get but it was better than freezing.






I ran through the basics, just because that is the first place to start. The static timing is still dead on and the dynamic timing is within spec. I did the timing belt 12K ago and replaced a bunch of parts, to include a new oil pump, windage tray, vacuum pump, and a new turbo at 442,000 miles.

While the valve cover was off, I checked the lifters because they have been noisy with the extreme cold but none of them had collapsed or had any play in them.




With a multitester and the Bentley, I checked the QA (N146), needle lift sensor (G80), start of injection valve (N108), and crank position sensor (G28), all were within specifications.




I still wasn't satisfied it wasn't the #3, so I swapped it out with another I had on hand that only had about 10K on it and that tested fine.




It ran the same way with the same Vag-Com results.




While the #3 was out, I checked what I could of the piston with a new borescope and did not see anything out of the ordinary.

But, what I did notice was that the oil was down, like barely on the dipstick. I topped it off right before W386's trip. He drove about 300 miles all together and somehow 1.5 quarts of oil was missing. I checked the intercooler and found about 1/2 a quart, or just over 400ml when I measured it. I drained the intercooler before he left as well, so it was empty. The turbo came from BoraParts and was new 11,000 miles ago but the car sat for about a year with me only putting about 1k on it in a year due to having to fix the floorboards.

W386 says the car still pulls fine but he didn't drive it that hard so he really doesn't know. I'll tear the piping off it and check it in the next few days.

I doubt this is the issue but more of an 'also' deal, so I'm still looking for the original issue that's causing the rpm fluctuations and fuel imbalance. It starts just fine but is never smooth and runs rough.

Any additional ideas are most welcome. I'll post up some Vag-Com shots next.
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
Here are some Vag-Com shots, but keep in mind the car is cold and the accordion pipe is removed due to checking the static timing. You can also see how much the rpms jump around.















 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Did you try bypassing the fuel filter and running it off a container?

Btw, what do you have your IQ set to? Are those values skewed, because the car isn’t warmed up?

-Todd
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
With the oil found in the intercooler, I think you may want to think about possibly checking compression.

Maybe.
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
My IQ is set to 6 normally to keep the smoke down.

I can check the compression, but the car never shut off or ran funny, so there was no runaway or hydrolock. My compression tester TDI fitting broke so I'll have to source another.

I did not try running the fuel from a different container since there are no bubbles in the line and it starts instantly. I can easily though since I have fittings for doing a Diesel Purge.
 
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whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
If something is cheap/easy but not as likely or expensive/hard and more likely, I go for the cheap/easy stuff first.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Mark this is really puzzling and I share your frustration at not being able to easily identify the problem. I think you mentioned before that you checked static timing and it was ok?

I know for a fact that you treat your winter fuel heavily so I have no doubt that the fuel quality is good, nor do I believe that there's a problem with your filtration unless something odd from inside the filter managed to come loose and travel into the pump, which seems unlikely.

Without really knowing how much your screen shots deviate from normal, or how much the cold would affect the readings I'm wondering if the readings are symptoms of a problem inside the IP? I'm not really very familiar with how the ECU achieves stable idle other than it must do it via the IP with sensory input.

All I can offer is to send you my compression tester if that would help. I think I have an adapter in my old kit that will work with the TDI GP threads, I'll have to check on that. I haven't used it in a long while and it's from the early 90's.

It's been miserable cold here too, we're just finally coming back above zero today, I ran my car every day this past week in sub-zero temps without incident so I really can't imagine what could have happened 'all of a sudden' that would bring this on.

EDIT: I am somewhat concerned about the 1.5qt of missing oil, if that was pulled into the combustion chambers somehow that might have some bad consequences.

Steve
 
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Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
I think a compression check is in order.

Also, run a basic setting 04, post the results here. That at least can show us if the pump has adequate case pressure by proving it can adequately control timing advance.

Is this engine still all original? Original pistons?
 

Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
What stinks about the 1Zs is the pistons. I mean, yes, they can go hundreds of thousands of miles with seemingly few issues, but most of them eventually seem to develop piston slap in #3 first, and score up the cylinder walls a bit, even on well-taken care of engines.

AHUs and ALHs don't seem to do that with the updated pistons they come with... But there definitely is a pattern failure of the #3 cylinder on 1Zs as they get up there in mileage.
 

greenskeeper

Top Post Dawg
Joined
Mar 10, 2003
Location
USA
TDI
1998 Jetta TDI
check the IP harness, I remember having to repair that due to age at one point and I believe it gave me goofy IQ readings and idle
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
I repaired this once already since it was a swapped pump. I thought of that and it checked out ok.

The turbo is blown, so once I get back from vacation I'll toss the 442,000 mile original one back on and send this hybrid back to Bora for diagnosis as to why it failed at under 12k miles. Needless to say, I am anything but pleased but we'll see what becomes of it. I don't beat on my cars, never abuse them, and you can bet it was installed properly and primed before initial use. Aaron and BoraParts are good people though, so we'll see what happens.
 
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KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
My '98 developed a lopey idle, timing jumped all over the graph, idle IQ jumped randomly from maybe 2 to 9, surged like crazy at parking lot speeds and even a little at highway speed on a very slight downhill. The injector balance was off but I don't recall it being as bad as yours.

Drove it like that a long time while trying to figger it out since it drove ok so I don't recall the mileage or if the symptoms came on gradually or all at once.

Anyhoo, the fix was a another pump. The replacement had broken insulation on the timing solenoid so I swapped that with the original pump. This would seem to exonerate that part as the cause of the original problems.

Haven't gotten around to opening the old pump up to see if there's anything obvious wrong with it. During the troubleshooting I checked all the usual suspects that folks suggest including a set of new nozzles balanced by DBW.

Got a spare pump to try?
 
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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
I’m confused.... was the rough running and odd injector balance caused by a damaged nylon fuel line?

-Todd
 

Lenard

Active member
Joined
Apr 26, 2017
Location
Lake Mills, WI
TDI
02 Beetle "skeetle" Previously: 98 ahu jetta, 05 bew jetta, 97 1z b4 sedan, 2004 bhw passat, 02 alh jetta, 2005 bhw passat, 97 b4v glx 1z swapped, another 98 jetta. Honorable mention: 81 jetta coupe 1.6d
Abacus, I am going to assume you've already performed a ventectomy? After fresh timing, injectors, vacuum lines, dynamic and static timing good to go and some wire repairs at the IP harness, I was still battling a lumpy idle. I was also having trouble fueling the car. So I gutted the vent button and used some hose to physically push the vent flap open. Lumpy idle has disappeared and now I can fuel my car! I thought it was crazy how simple the fix was, but also crazy that it turned out to be the last thing you'd think would ever make your car run like poop.
 

Lenard

Active member
Joined
Apr 26, 2017
Location
Lake Mills, WI
TDI
02 Beetle "skeetle" Previously: 98 ahu jetta, 05 bew jetta, 97 1z b4 sedan, 2004 bhw passat, 02 alh jetta, 2005 bhw passat, 97 b4v glx 1z swapped, another 98 jetta. Honorable mention: 81 jetta coupe 1.6d
I assumed you had done it already. You seemed to have looked into most logical answers so I figured I'd give you something stupid to try lol. Kind of like the "did you try unplugging it and plugging it back in?" thing
 

Lenard

Active member
Joined
Apr 26, 2017
Location
Lake Mills, WI
TDI
02 Beetle "skeetle" Previously: 98 ahu jetta, 05 bew jetta, 97 1z b4 sedan, 2004 bhw passat, 02 alh jetta, 2005 bhw passat, 97 b4v glx 1z swapped, another 98 jetta. Honorable mention: 81 jetta coupe 1.6d
Have you got it figured out yet? Curious as to what caused it
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
I've been on vacation in Mexico and am currently sick with the flu. Im swapping turbos this weekend and will report back.
That's not good, as aja8888 mentioned it's a bad one going around from what I understand.

Since I don't react well to vaccines I don't get them, but if I'm somewhere and I start to hear a lot of coughing I do an about face and head for the door.

Also I hear the vaccine for the current version of the 'plague' is not very effective anyway, something like 32%.

Steve
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
My wife is a doctor and she said the vaccine is only 6-10% effective this year. Apparently the WHO chooses the combination of strains that makes up the flu shot and they changed their decision making paradigm yo try and increase the effectiveness. They chose poorly.

I don't get one either but she mentioned early in the season that I should due to battling a respiratory illness last year. She recently said I shouldn't bother getting one.

But I'm trying the same thing: avoidance. Not sure it's working too well.
 
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