Crappy idle,AFR all over the place

[Side-Step]

Let's see if I can break it down.
99 AEB 2L stroker

Had a ICM go bad a week ago. Car ran good after that. Then, the car
started to idle crappy(up and down) and die if it was left idling.
Checked for vac. leaks - none
Fuel pressure - good

Check the wideband and the AFR's were all over the place.

Drove the car for a long time(5hours straight)...under power runs good, but
when decel'n, the CEL blinks and AFR goes high (lean). I give it some gas and it goes back to normal.

Checked the codes and had a MAF and misfires(from the ICM going bad)
I bought a MAF and still no change.
Could coils cause this problem?

Simple problem: Idle=crappy(seems like it's missing) Driving=good not great

Thanks for the time

[Poopie]

you only had two codes? check your engine control/timing fuses.

[Side-Step]

The car will still run if those fuses are bad? I'm walking out to check them now.

[Side-Step]

No dice.

What causes the idle to "hunt"?

[Oricle]

No dice.

What causes the idle to "hunt"?

Is this at anytime you are not on the gas?
Such as when just idleing at a stop light your idle will start going up and down and your vaccum as well?


I'd clean your throttle body.

[Poopie]

check for intake leaks and of course do a boost leak check

[bassed]

If it's running MIKA Tunning that's the issue I'd bet.

[pipe7284]

Mike tune sucks. I have it on my girls gtrs and wish i could spend the funds on a knew software for her, i still gotta finish my car. So later i`ll be going unitronic or ctapp.

[Side-Step]

Think I fixed the problem. I changed back to my 630's and lowered my FPR.
I also hooked it to a Vag-com setup and was able to reset the TB.

I'm getting alot of misfires at idle though. Checked around for leaks, switched everything around ie:coils,injectors,and plugs. Even put new plugs in. Thinking of getting better coils for a hotter spark.

By the way, what is everyone running there fuel pressure without the vac. hooked up?

[mike-2ptzero]

Did you check for exhaust leaks, because a exhaust leak before the 02 can cause the AFR to be lean or hunt since the ecu keeps trying to adjust for the difference in readings.

My wide band hunts at idle all the time but only because my 02 sensor is right at the exit of my turndown.

[Side-Step]

Did you check for exhaust leaks, because a exhaust leak before the 02 can cause the AFR to be lean or hunt since the ecu keeps trying to adjust for the difference in readings.

My wide band hunts at idle all the time but only because my 02 sensor is right at the exit of my turndown.

I do have a very small exhaust leak at the v-band clamp(turbo to downpipe).

I bought a new one, but no dice. I'm going to loosen up the downpipe and see if it could be twisted.

[Side-Step]

Idle it still up and down.

I have a catch can that recieves vac from intake side of turbo, but I have another vac that hooks up to the intake mani. Can I take that off and plug it off or put a filter on it. Then just plug off the port on the mani.?

[mike-2ptzero]

Idle it still up and down.

I have a catch can that recieves vac from intake side of turbo, but I have another vac that hooks up to the intake mani. Can I take that off and plug it off or put a filter on it. Then just plug off the port on the mani.?

What type of catch can you using and how is it setup?

[k0mpresd]

By the way, what is everyone running there fuel pressure without the vac. hooked up?

3 bar with no vacuum. 1008cc injectors. car idles fine. took some fine tuning though. to put it lightly. pretty steady 14.7 a/f though.

[Side-Step]

What type of catch can you using and how is it setup?

I don't know the name of it, but it has a "in" and a "out" or vac. side.

The block vent is "y'd" off under the intake mani. One line goes to a metal line around the back side of the head, which is where the catch can is hooked to. The other line goes to the intake mani port. I wanted to just keep the catch can only, but didn't know if I should plug or install a filter on the other line that goes to the intake

Thanks for the time.

[Side-Step]

3 bar with no vacuum. 1008cc injectors. car idles fine. took some fine tuning though. to put it lightly. pretty steady 14.7 a/f though.

Thanks and what is the pressure with vac.? Just to compare.

[k0mpresd]

no idea. i dont have a pressure gauge anymore since im not running an adjustable regulator.

[Fink_tha_Audi]

I had a similiar problem when I got my car (99.5 A4 AEB) back fro the shop (ran good for a while), throttle body alignment was off there is a forum out there that shows how to re-align it. Once I did that it ran awesome

[Side-Step]

I had a similiar problem when I got my car (99.5 A4 AEB) back fro the shop (ran good for a while), throttle body alignment was off there is a forum out there that shows how to re-align it. Once I did that it ran awesome

I did that three times on Monday. Yesterday afternoon, my wife came home and the car was running fine. I did bump up the fuel pressure some(from 38 to 42 with vac.)

Would like to strip off this crank case vent line.

[Side-Step]

With the other items that needed to be replaced, I've found a bad PCV valve. I've tried to find any post on AEB catch can setups. This motor has two lines coming from the block breather.

Here's the question. Does the motor need vac. on the breather or can I just hook both lines together and run it to a catch can? Then have the catch can vented to atmosphere.

[mike-2ptzero]

With the other items that needed to be replaced, I've found a bad PCV valve. I've tried to find any post on AEB catch can setups. This motor has two lines coming from the block breather.

Here's the question. Does the motor need vac. on the breather or can I just hook both lines together and run it to a catch can? Then have the catch can vented to atmosphere.

Are you talking about the stock PCV system? If so, there is only 1 line that goes to the block, that is the hard pipe that runs behind the block. It goes into a hose which then splits off, one side goes to the intake manifold and the other goes into a plastic piece that bolts to the block but then goes further forward into a round hole. If you do a atmos vented catch can you want to plug the line going to the intake manifold other wise you will be sucking in unmetered air. Then just run a hose to the catch can, making sure the can sits higher then the block breather. The easy way to do this is to use the block breather from 034 that goes right into the OEM part that is bolted to the block.

Here is a picture of my car back when I did my new catch can using the 034 adaptor, I used -10 fittings and lines.



Adding a line to the back of the valve cover also helps reduce the pressure pushed up into that area.

[Side-Step]

Thanks Mike.

That helps. I just plugged that intake hose and capped off the intake port.
I'm going to take a look at the piece that you have in the pics. Cleans stuff up some.