Cold Start Problem

[kenm55]

I have an annoying Cold Start problem, after i start the car the engine will start to hunt that is to say the rpm fluctuates from about 1000 to 2000. Has anyone come across this before? Have checked all the sensors and the throttle position sensor (via the computer) and even changed computers to no avail....:huh:

 

[thirteen]

The cold start is about 1500 rpm and comes down to 750 rpm (+/- 50 rpm) once
the engine is at operating temperature.

 

[CLuTZ]

Sounds like your FIAV is stuffed.....

 

[BYBY5L]

the fast idle screw's o ring might be nackered, if the screw wont screw all the way out then ya might need to take the throttle body off an push it out at the same time you unscrew it,
hope it helps,

 

[EVO-00X]

One of either 2 things to check again....
1) Idle stepper controller that is bolted to the underside of your throttle body (has water hoses going into it).
2) Throttle Position Sensor also on your throttle body. These bastards do the same thing when just a tad off alignment.

Try unplugging the idle stepper motor with the engine running first and see if it changes anything. If it doesnt do anything then thats what is probably stuffed. Let us know how you go.

 

[kenm55]

Thanks for all the replies:thumbsup:
Have reset the TPS and logged it last night so all is good there will try unplugging the FIAV tonight and see what that does and post back.....

 

[brisvr4]

You can't unplug the fiav. You can unplug the idle stepper controller. My money is on the Fiav being stuffed. There is a easy fix if it is that though.

 

[EVOCPE]

How did you reset the TPS??

Sounds the same as the problem i had a while ago, but mine was cause the TPS wasnt adjusted properly

 

[kenm55]

@EVOCPE
I have ECMlink lite Great package by the way. It told me my TPS was reading 2% with foot off so adjusted it back to 0 then logged the TPS from 0 to full throttle (was reading 97% with foot flat)right clicked on the log scrolled to "Adjust TPS" then did a second log to check and all good
@brisvr4
Whats the easy fix?

Update:
I pulled the plug that is under the throttle body and that made it cycle even faster i have a spare one on another car so swap will that out today and see if it cures it....
thanks for all the replies will keep you posted

 

[BMGTZ]

gee your old kenm55......oh btw old fella. lets swap the throttle complete throttle body off that engine i just bought. if it fixes problem.....we know where to look.....if not well lets look elsewhere

 

[andy's-galant]

yeh i had same problem and it was tps not adjusted properly, i found you have to do properly

 

[kenm55]

Update:
Replaced the ISC valve and removed/replaced the Idle Air Bleed Screw ( needs a new one ) but is still hunting when cold :thumbsdown:going toremove the whole throttle body next and go over the whole thing...