Anyone that has run into an issue similar to this i would appreciate any input - you'll have to bear with me as i try to describe this.

Some background info:
I got an automatic 99 LS and added a supercharger to it and changed it to a manual. Before the auto-manual change i also added a e-Manage system to adjust the timing. When i changed it to a manual, the e-Manage was still in place and i decided to change to ODBI to eliminate any issues with the ODBII programming (O2 sensor error codes, lower rev limiters) etc. So now I currently have an ODB I with an e-Manage system and a supercharged manual setup.

The problems i'm having may all be related to one thing.

Symptoms
I have a remote starter and if i try to start it up that way - the engine starts up revving to about 1100, but right away after the car seems to have started and the remote starter is no longer cracking the starter the RPMs drop as low as 200-300 and the engine dies right away. If i start it manually with a key and i press the gas a bit to get it over the initial drop in RPMs, and then later on ease off the gas pedal gradually, it will stay on, but still low rpms (~300 rpms). This could be that the idle is not adjusted properly ...

The other thing is that ... now it takes ... over 15 minutes (but more towards 20-25) to warm up the engine to a temp where the needle on the gauge would climb just a little higher than quarter way, when the fans kick in and the RPMS drop down. WHY would an engine take that long to warm up??? Even if i start driving it, the temp would not climb to where it should be ... only maybe after 10 min into the drive?

I remember this engine being as smooth as anything and taking less then 5 mins to get up to the proper rev temperature and settle down right away. Now? - not only it doesn't rev as it should at the beginning, but when it starts to rev, it will rev for longer time ... until the engine is warm.

I recently replaced the thermostat and that helped a bit with the engine warming up (before when i was driving it the temp was actually going down - below C :-) And i tried to adjust the idle - even though i did it from the top screws on the throttle cable instead of the rev adjuster on the throttle body.

So my questions are:
Why would it take this long for an engine to warm up (over 15 mins)? Any ideas on this?
Why would the engine stay revved, even though it's warm?
Why would the RPMS drop like that every time the gas is disengaged?


Any ideas welcome.

 

Bad thermostat is most likely the temp problem

The "stays revved" part could be that the engine is up to proper operating temperate due to the bad thermo, thus its still raising the idle in order to warm it up. It might also be a bad IACV, bad base idle, sticky throttle cable and/or bad tuning on your emanage (or a combination). I'd fix the thermostat first and then unplug the IACV and set my base idle....then try to trouble shoot from there.

 

I already replaced the thermostat before I wrote that post. So the engine is warming up ... it just takes a looong time.

I'm still not quite understanding why it would still rev high after driving it for a while and after it's obviously up to proper temperature. I checked the cable and its not sticky.

The programming on the e-Manage was done a while back and i have not had a problem with the engine revving like this before.

Do you recommend a way to test the IACV for problems?

Thanks

 

What brand thermostat did you use? The ones from autozone and from pep boys are cheap pos that dont work. Thats from personal experience and from searching. In my case, it was bad thermostat, replace thermo, replace thermo again, replace thermo one more time w/ OEM unit.....then shortly after replace the temp sensor in the head. If the thermo is staying open in the cold weather, it might not be up to proper temp....that coupled with a dummy gauge can make "normal" temp not so normal. Best way to check the IACV is to unplug it and see what the base idle is at. If its ~500 then its the IACV, if its high then it might be a vacuum leak or a bad FITV (assuming its a pre-96). Basically unplug the IACV and if it stalls out/idles at 500 or below, then the IACV/ecu/temperature is the problem (being that it could be a bad iacv or a bad signal going to the iacv due to the ecu trying to correct for other issues).

 

I used a Beck/Arnley 170 Degree Thermostat from Advance Auto. But you're telling me those are not the same as OEM's? Other people also think they're not really up to the job and they leave the car idling a lot longer (about 15-20 mins) than an OEM (3-5 mins).

You definitely think i should replace the thermostat, eh?

Why did you have to replace the temp sensor in the head? Did this have anything to do with the thermostats you went through?

It's not a a pre-96 - it's a 99 LS.