Intermittent Rich Condition and Sporadic Idle

[RallyeBourne]

1999 1.8TQM
176,000mi
k0mpressd tune
TP
ICM Delete/FSi coils

Hey Guys,
Definitely need some help, the fiancé is getting irritated and already wants me to sell the car. I'll try to put this in a easy to follow timeline, but I'm at my wits end so bare with me.
Car was running tits with my k0mpressd tune and stock cat (tune has rear o2 coded out). So I decided to finally pull the trigger on a Manzo Test Pipe. fitment was just okay, but the hardware was slightly too big. Got new hardware and installed it. It placed the primary o2 sensor very close to the exhaust manifold. I started experiencing this issue. Occasionally, upon taking off, the car will start to sputter and go super rich ~9.2-9.5 afr. If I take my foot off the gas, idle will dip from 900 to 300 and back up, and eventually stall. When I restart the car, the issue is gone. Also, when the car starts to do it, I can turn it off before it stalls, restart it and all will be well. I replaced my cam position sensor since I knew my connector was cracked. Problem persists. I bought a new o2 sensor and a new o2 sensor bung, plugged the primary port, and welded the new bung into a position farther from the manifold and downstream a little from the turbo (thinking I'm just overheating the o2 sensor). I also heat wrapped the testpipe and coated it with the silicone stuff made for exhaust wrap. Problem persists.

What. The. Fuck.

Obviously, the spark to ignite the powder keg was installing the testpipe. But with the rear o2 coded out, I don't see how that could be the culprit. If I'm wrong, educate me.

I can't keep throwing money into it blindly. I normally try to figure these things out on my own, but I'm out of ideas.
MAF? N75? Leak? 710?
I have VCDS and can do logs of whatever you guys need, only limited by the free version.

It's hard to defend the car to the lady when it has a persistent problem. I refuse to sell the car, I just don't want to lose a fiancé over it.

EDIT: Car is not throwing any codes.

[RallyeBourne]

Just tried unplugging the MAF, car ran like shit and stalled. Couldn't keep it running.

[MetalMan]

Just tried unplugging the MAF, car ran like shit and stalled. Couldn't keep it running.

Try clearing codes (to clear fuel trims) and then unplug the MAF. If it still runs like crap then there's definitely something going on.
Speaking of fuel trims, what are they?

[RallyeBourne]

Cleared and unplugged. Car is holding now. Since the real issue is intermittent, I'll have to roll like this for a bit to see if it comes back.

[RallyeBourne]

Nope, came back. Problem is becoming more and more frequent. To the point that turning the car off and back on doesn't always make it go away. Which inspires confidence when I'm 76 miles from home and it's raining. Yay.

Also noticed an oddity. When I replaced the o2 sensor, I cleared the ecu. But before I cleared today, I accidentally clicked on readiness, and the oxygen sensor circuit was "failed or imcomplete." I've ALWAYS had all passing. And upon previous clearings, I've always reset all monitors to passing within a day. Now, weeks later and with and brand new Bosch o2 sensor I'm failing? What the hell.

[MetalMan]

Just to get the "obvious" things out of the way:
-boost leak test?
-checked DV for apparent proper operation?
-no exhaust leaks between engine and primary O2 sensor? (manifold gasket, turbo gasket, cat gasket)

Which O2 sensor did you buy? On my 1998.5 I bought the primary O2 sensor for a 1998.0 by accident, and it failed readiness check. I believe the correct sensor for your car (1998.5-1999.5) is Bosch 15160.

[RallyeBourne]

Caught a video of the issue.

Idle Issue - B5 A4 1.8T: http://youtu.be/a419AZwLKto

[RallyeBourne]

Just to get the "obvious" things out of the way:
-boost leak test?
-checked DV for apparent proper operation?

Which O2 sensor did you buy? On my 1998.5 I bought the primary O2 sensor for a 1998.0 by accident, and it failed readiness check. I believe the correct sensor for your car (1998.5-1999.5) is Bosch 15160.

I did a leak test when the issue first started, but I've replaced a few things since then. I should do another. It's always possible I knocked something loose.

I have not checked the DV. I will do that in the morning. What am I looking for specifically? How would I know it's malfunctioning, aside from obvious tears?

I bought 15160.

[RallyeBourne]

No leaks found. DV seems fine.

Car just keeps getting worse. Can't drive it today at all. Fuck.

[RallyeBourne]

It has to be something electrical, right? Why else would turning the car off and back on reset it? Granted, that doesn't seem to work anymore, but still. If it was mechanical (leaks, etc.), it would have been present all the time. So what sensors could cause this? Bad MAF? I cleaned it this morning and it didn't get any better. Crank position sensor? Throttle position sensor?

[MetalMan]

Have you tried a forced throttle body alignment? (not sure if VCDS Lite can do it)
TPS is part of the throttle body assembly, and is something you can log with VCDS.
Could very well be the throttle body going south; there is a motor in there that controls idle.

EDIT: I will admit, I haven't seen the video. Youtube doesn't function on my work computer and I don't usually have time to check the forums at home.

[BaseDrifter]

Just from that video it looks like a serious misfire, might be worth trying new plugs/coil packs? That doesn't look like something doing a throttle body alignment will fix to me..but it's always worth a shot.

[RallyeBourne]

Didn't think about that. I'll pick up some new plugs and swap them in tonight when I get home. VCDS Lite can do TBA, but only on registered version ($99). I've been putting it off for too long. Time to pay the $99.

[RallyeBourne]

Switched out the plugs for new bkr7e's. Dropped the gap from .040" to .036". Car is drivable now. Wasn't this morning. We shall see when I take her to work tomorrow.

[MetalMan]

How did the old plugs look, and do you have an idea how long they were in there? (were those also BKR7E?)
In for updates.

[RallyeBourne]

Plugs looked decent. Little dark, but not bad. And gaps were all still correct, except #3 was .038". Also, cyl 3 plug came out with no force from the ratchet. Was threaded in, but very loose.

My drive to work today was okay. No idle issues, but my afr's varied between 13's to 15's at idle, where I'm normally right at high 14 to very low 15.

[MetalMan]

Plugs looked decent. Little dark, but not bad. And gaps were all still correct, except #3 was .038". Also, cyl 3 plug came out with no force from the ratchet. Was threaded in, but very loose.

My drive to work today was okay. No idle issues, but my afr's varied between 13's to 15's at idle, where I'm normally right at high 14 to very low 15.

AFR should vary from rich to lean during normal closed loop driving when the ECU uses a narrowband primary sensor. 13 does seem a little rich but since you recently reset the ECU (by clearing codes) it may just need time to adapt the fuel mixture.
Just out of curiosity, is compression good?

[RallyeBourne]

Haven't done a compression test since this issue popped up. (Did one right before deleting ICM many months ago). I'll do a check tomorrow.

[RallyeBourne]

Welp. She acted up a bit on the way home. Same symptoms: sitting at a light, car warm (climatronic screen read 90* C), afr drops to 9, car stumbles and recovers, stumbles and recovers.

[Avant Nate]

leaking injector? Are you getting misfires in any particular cylinder? Vcds should tell you

[RallyeBourne]

Since all the plugs looked good,

I talked to my old service manager. He suggested an exhaust leak. He told me to run a seafoam treatment through, because I'll be able to see the smoke coming out any leaks.


Really hoping that's a gasket issue, not a cracked exhaust mani or turbo housing.

[RallyeBourne]

Picking up the gaskets today. I really hope that's all it is. I don't want to have to buy a new turbo now, only to have to upgrade later.

[RallyeBourne]

Working two jobs REALLY gets in the way of things...

But, I brought my B5 to work to start pulling it apart. Started working on it on my lunch yesterday, got most of the shit out of the way. Today, I got the mani>turbo bolts off. Amazingly, I didn't shear any of them! Took some damn work though. Lots of torch, pb blaster, and back and forth. Def replacing that hardware though.

[RallyeBourne]

you can see the blow by here

[MetalMan]

Soooo.... it's fixed?

[RallyeBourne]

Yes and no. Fixed the gasket. Holding better boost pressure. BUT, while running it to burn of the peanut butter blaster, I noticed fuel in my boost gauge line. It's tapped off the fpr. So that's obviously gone bad. That could be my real issue, not the gasket. We shall see when the new fpr gets in.

[ElliottG]

My dad has a very similar problem with his 2.0 Golf...interested to see the fix...good luck! Keep us posted.

[B44]

can it be carbon buildup?

[RallyeBourne]

Definitely not fixed. Just did it again. I think it's the fpr.

As for carbon buildup, I doubt it it would take a hell of a lot to do this, and looking down the plug wells, there isn't much buildup.

Guess the car sits at work until the new fpr comes in... I miss my baby... :(

[RallyeBourne]

[ricekikr]

Have you tried disconnecting the n80-intake manifold hose (plug intake and keep n80 just open)? In my b5 it caused the engine to stall in the middle of the road (pegged my afr gauge - rich), in my previous non-audi it caused erratic idle, engine quitting, rough running (didn't have a wideband).

Non-audi - the valve didn't close, upon dissection the seal that seals the valve was rotted.
In the b5 - it was still sealing, don't know why it caused to run rich. Just disconnected it, started the car back-up and never re-connected it.

[RallyeBourne]

This little chingadera? So I just plug the intake side, and leave it connected?

[RallyeBourne]

For the first time since I've been using them, I'm very disappointed in Autohausaz.com. I placed my order last week, and it finally shipped out Wednesday evening, and won't be here until next tuesday. I've never had it take any more than a day to ship out, and two days to arrive, but I always count on a week. Now we're looking at nearly two weeks. Kinda pissed.

[RallyeBourne]

So I got home yesterday, and my shit was there. Which is odd, considering the tracking info shows its still about 100 miles away. But whatever.

Put the new fpr in, and low and behold, I'm still having issues. But they're different issues. Now I keep going lean at part throttle, but full throttle gives me perfect afr, as well as all of my boost back. I'm hitting 17psi, holding 16psi. I'm going to try to do a smoke test today or tomorrow at work. See if there's any leakage.

[RallyeBourne]

Perhaps, I should remember to clear my fucked up fuel trims when I make changes. Did so today, and she's back! Running great, boost is back, idles perfect. I'm stoked.

[ricekikr]

This little chingadera? So I just plug the intake side, and leave it connected?

Yup.

Perhaps, I should remember to clear my fucked up fuel trims when I make changes. Did so today, and she's back! Running great, boost is back, idles perfect. I'm stoked.

Good. I just ordered one a few days ago hopefully it fixes mine too.

[RallyeBourne]

Yeah... my issue persists... Happened twice on my way to work today.

I fucking quit.

[RallyeBourne]

Thinking of just replacing these two. Just tired of blindly throwing money at it.

[MetalMan]

I may have a spare Bosch N80 (EVAP Purge Solenoid) in my parts bin, that I swapped out as part of my "throwing parts at it until it's fixed" for my old AEB car. The N80 wasn't the problem so my old one should still be fine.

I'm pretty sure it's there, and if it is you're more than welcome to try it out. If it solves your problem (and you keep it) I would only ask for $15.
Can bring it with me to work tomorrow too.

Also the"BWD Vacuum Control Solenoid", if the picture is correct, is the suction jet pump. I am pretty sure your car doesn't have one?? (only ATW/AWM manual/automatic and AEB automatic cars have it)

[RallyeBourne]

That would be amazing. I still owe you beer from the last time you helped me, too. What's your poison?