Idle Issues

[stefan]

I made a more final intake for my B6 and now its idling weird. sometimes it searches up and down. for example when you hit the clutch... or turn off the headlights. It searches up and down progressively higher/lower till it stalls.

[leapin]

Now I know when my dad and I rebuilt his 5.0 he had the same issue...any thing to upset the idle and it would search and stall. His turned out to be a bad intake manifold gasket. The gasket was brand new but didnt seal right. Just an idea.

[sasquatch]

maby you have a cracked or bent intake manifold. check it all over for cracks and put a ruler on the mounting plate to make shure its straight. while you have your intake off check the head too.

[stefan]

I dont think there are any leaks... I sprayed starter fluid all over the other day and the idle didn't change.

[jglutz]

Check all of the intake air ducting prior to the throtle body. Make sure there aren'tany leaks.

Monitor the fuel pressure while the idle is hunting. Should always be steady.

Check all of the idle input control devices and wiring....ther might be a little current leakage...this includes...Headlights...Cooling fan...Park/Nuetral/ingear/clutch.

[stefan]

Ok. I Had it running fine last sunday. I put 300kms on it no major problems.

Now I redid the intake to be abit more permanent now im getting these problems. The cone filter wouldn't have anything to do with it?

I thought It maybe was the Idle air control... I soaked it in seafoam and no change.

Now the check engine light is flickering when I let off the gas/coast/shift/exct.

It only starts acting up once its good& warmed up.

[PaulS]

Stefen,
I had a problem with idle and rough running after the car was warm, and it turned out to be the ECT sensor. Check the code from your Check Engine light , and if it is nine , it is the ECT.

[stefan]

I thought the light had to be ON to retrieve the code. Mine is only flickering now and then.

[miami man]

it might not be any connection to your problem but for the new people here is that mine had an idle that would go up and down in rpm worked on it but never found the problem until i dropped a wrench on the vaf wires and it changed rpms so i shook the conectoer and for sure was the problem all along and it took me a year to find the problem.

stupid me

[jglutz]

CE Light Flashes....No code stored
Could be a sensor/wiring problem....what ever is failing...driviving the CE light on...is also causing a power loss...or open ground...to the ECU...thus immediately resting the code.

FB71 Help needed...Jim...with the idle problems....I'm wondering...what conditions cause the ECU to go into "limp/open loop" mode...Based off this list...these are the things I would start checking.

[stefan]

Ok it hasnt been doing it much latley... No idea what changed!?

Other observations/problems...

I notice that when its cold (like morning) It has much more low end torque... but once its warm there is basically no low end torque.. gutless till about 2500

Also, I dont seem to be getting very good gas milage... is this normal at first for a rebuild?

I replaced the o2 sensor today for good measure but it dosent seem to have made any difference.

[edudu77]

Mine was doing that, sorta, ran great when cold, then about midway through heat up the CE light would flash and it would run like crap, then when warm it ran okay..mileage sucked! I pulled the connector off of them temp sensor...right by the fuel injectors, and hooked up my ohm meter. Should get between 2000-3000 ohms cold and 200-400 ohms warm. Mine would just flicker when cold...generally would show 1950 for about a second...then nothing. When warm it showed about 750...the computer just had no idea what to do apparently. Mine finally threw a code one day...it was code 9...but it had run like that for a month with no code. I only got the code after I rebuilt the top end..strange. Hope this helps...oh yeah, part was 19 bucks and now I am getting 36 mpg around here in the mountains, up from 23 mpg.
Donovan

[FB71]

bingo, temp sensor.

[stefan]

Thanks guys... Ill try get one tomorrow. (Hopefully It won't be special order!)

[stefan]

Ouch... It was in-stock but it cost me $60 + %12 Tax.... Gotta love canada!