I hope that you guys flame me for being so stupid but let me tell you what my problem is. My car was started a couple of days ago but it ran really rough. Erratic idle, bogging down close to boost, just running poorly. So we adjusted the throttle position sensor and got it to run really well. We turned it off and started right up again. The next morning I went to start my car and it would not start at all. So the car runs really well and starts easily when the engine is warm but it wont even start when the engine is cold. You guys have been such a great help to me in the past please dont let me down now. Thanks.

 

What exactly did you do to adjust your TPS?

 

At first we adjusted according to the proper voltage, but then we adjusted it almost completely counter clockwise in order to smooth out the erratic idle. Basically the cpu thinks that the butterfly in the throttle body is open.

 

I'm wondering, why would you do this? If your TPS is adjusted really badly (voltages are very far off), the car wont run or start and die immediately. I would adjust it back to within the normal parameters.

I'm not too sure why the car would start well when car is warm, but not when its cold. I've heard that the voltages may differ when the car is warm, which is why its recommended to adjust the TPS when the car is warm.

 

OK I adjusted the TPS back to within voltage parameters after the engine was warm and it has the same symptoms. Someone please help. This thing idles terribly and is very hard to start when it is cold.

 

Does your car still have the cold start on it?

If not this may be your problem, when starting you car up give it some gas if its possible to get the engine to turn over and keep it at about 3,000 rpms for approximatley 2 minutes, following this let go and see if it drops down to a steady idle.

 

I know that there is no coolant that flows through the throttle body but I dont know about the cold start. Would this cause an erratic idle when its cold? And what exactly does the cold start change?

 

Still having problems guys. Impossible to start when the engine is cold. If I adust the TPS I can get it to start but then it won't idle correctly.

 

you have PMs

 

your cold start has been removed... and yes, this will cause your engine rpms to fluctuate / die at idle when cold... The way the cold start works, when you first fire your car up (cold) it rev's your engine up to about 2.5 / 3k rpms to help warm the engine up. This is why when ever I drive my car, if its been sitting for a while and the engin is cold I crank the car up and let it idle for about 5 minutes, run around the house and do what ever I need to do then hop in...

if you dont have the cold start then you have to do the warmup your self, when u turn the engine over just rev it up to about 2.5 - 3k rpms for about 30 seconds and it should smooth the idle out

 

This used to happed to my car in the winter but all I would do is just let it warm up by its self like spoolage said. Rev the car a little to help warm it up and listen to backstreet boys while you wait :P

 

Guys I appreciate all your help but the car will not start when it is cold. To start the car I have to adjust the TPS all the way to one side but then it idles erratically after it warms up.

 

Timing? Vacuum leak?

My Second Gen wont even run when its cold. Just turns over and fires, but only when the starter is pushing it.

 

is the car expelling lots of black rich in HC smoke when you start it up. if it is you might have a vac line crossed or not hooked up at all. there is one that will cause a very rich idle that makes the car want to stall during a cold start up. its located right next to the intake of the uim and right above the oil filter. check for a hose there if you need more info i can send a photo of the hose and device connected to it. just pm me

 

Is it possible that the rotors inside the housing are mechanically out of time? Will the engine run at all if the rotors are out of time. We thought when we put it together that we did it right but I'm running out of ideas here.