SAiamNE

In the mornings when I go to start my car the cold start comes on whether I start the car in neutral or 1st. Idle sits at around 2k.
Everything seems normal until the car just starts to warm up. As the car warms the thermo-wax melts and idle drops. Anytime the idle sits between 1500-2000 RPM it surges very bad. By surge I mean jumps up and down between those 2 RPM levels. It’s like the thermo-wax is trying to push the idle up below 1500 and then the computer says no that’s to high and pushes it back down, and they fight.
It's embarrassing to sit at lights as it sits there just going up and down with me no where near the gas.
As soon as engine warms up enough to bump that cold idle below 1500 the surging goes away and all is normal again.

Could this be a dead spot in the TPS, if not where should I start looking? And finally how hard is to take out the whole cold idle thermo-wax stuff.. I don't even really need to take it out, just disable it. Is this a good idea where temperatures can get as low as -30 celcious in the mornings sometimes?


My last problem is in any gear after ~6k RPM's i loose all power (S5 NA). My power band really drops off almost instantly as if the timing is out, which it is not (just checked). Fuel filter is only a year old.No cats just a Mid-pipe. Clean air filter, new plugs.... The RPM’s increase consistently from 1-6k, after 6k you can very noticeably see the tach start to slow down, but does not stop. Still can redline it, but it feels unhealthy from what I am used to. Doesn’t feel as smooth as it once did.

Can anyone also point me in the direction as to where to start looking for both of these problems?
We can rule out problems such as fuel filters, plugs, air cleaner, timing.


Thank-you..

Sgt. Pepper

I have the same problem with jumpy idle when cold. I need to set my TPS soon.
When i'm idleing and my idle is jumping I just turn the AC on and off and the idle goes back down to normal, but once I start driving again and idle it will start to bounce again. I also notice when I have my headlights on and the idle is bouncy, I can turn off my headlights and the idle will go back down to normal. It's as if It's an electrical problem.

SAiamNE

I believe your's is a BAC problem... I don't think the it's the same as mine... Not 100% sure though..

Mine doesn't just go up and stay there.. It constantly bounces up and down...

Anyone else care to help us out?

Icemark

Both of you have a bad or mis-adjusted TPS, and it sounds like saiamne in addition your VDI is not working, but the high rpm drop could also be TPS.

SAiamNE

I just replaced my TPS and adjusted it to 1Kohm once the car is 100% warm. The car still hunts very badly during cold start. My VDI was not working because my air pump belt feel off, which has since been replaced.

Can anyone lead me to why else my car is still hunting during cold start? Does this have anything to do with the idle screw located on top of the intake?
Please help..

Thanks

SAiamNE

TTT Please help....

SAiamNE

Ttt....

HAILERS

What is your idle speed when your setting the tps?

SAiamNE

I unplug the TPS when measuring as i don't think your suppose to measure resistance in a closed circuit..
Idle speed once warm is good.. around 750-850RPMS... The odd time sitting at a light with no brake on the idle will for some reason sit at ~1100-1300 RPMS...
If i blip the throttle it will go back down to normal idle..

Also can i lower my cold idle RPMS? I hate sitting at lights with it at 2500 RPMs when it's very cold.

bobafc3s

i have this problem sometimes but usually it stops and drops to idle at 750rpm

SAiamNE

Ttt

SAiamNE

Ttt..