temp question

[Rick V]

Where should the temp guage ride, when the car is warmed up? I'm fighting an idle problem and think the temp is the result. It is riding below the first line.
Thanks
Oh I'm working on an 87 944S

[pozican]

On my 86 turbo that is right where mine sits.

On my 87 NA it sits right at the middle line.

Dunno about the S :\


What's the problem?

[Rick V]

Originally posted by pozican



What's the problem?

High idle, when "warm" the car idles at 1100rpm. I can bring it down with the clutch and it holds. I don't have any vac leaks and everything is working. It is just won't idle down. I ordered a thermostat. I believe this to be the problem. Everything else is less than a week old.

[Eldorado]

have you tried adjusting the idle valve? lol

[Razorback1980]

Is the idle control vavle new? If not, you may want to try and clean it.

[Rick V]

I cleaned the IACV when I had the intake off. I reasonably certian the problem is the thermostat. When I finished the car it was 70 deg and it idled fine, 900. Of late winter has shown up and the temps are around 30 deg. The idle is now 1100.

[Razorback1980]

Another option is the temp sending unit that tells the DME what the engine temperature is. It could be reporting the wrong temperature back to the DME. In other words, the temperature sending unit that controls the temp gauge you see in the dash is not the one that reports to the DME which controls the idle. The one for the dash is in the radiator, the one for the DME is in the block in the front on the left hand side...if I remember correctly.

[Techno Duck]

The DME temp sensor is really just a trigger for the DME to switch fuel maps from 'warm up' (rich mixture) to 'normal' modes. A sensor going bad typically never tells the DME that the engine is up to temp and the car will run rich all the time. I dont think that would have an effect on idle though (but i could be wrong).

Also the idle is not adjustable on the 16v motors, they use some kind of electrionic idle stabalizer (im not refering to the ISV under the intake which is different).

I dont get what you mean when you say you can bring the idle back down with the clutch. You push the clutch down and the idle drops?

[HondaDustR]

do S models have an idle position switch on the TB like NA cars? Maybe it gets flaky when warm.

[Razorback1980]

I think what he means on the clutch controlling the idle is when he puts a load on the engine using the clutch, the rpms drop. Then when he pushes the clutch back in, they stay dropped. It almost seemed to me the computer was holding it at a richer mixture because it doesn't know the engine is at operating temperature. Other thoughts I had were the Throttle position switch which would be something he should probably check to make sure it's working ok. Oxygen sensor was also a thought. But I don't think it's the thermostat.

[Rick V]

Ok The "clutch" test is where I put the car in gear, hold the brake and let out the clutch slowly until it starts to grab. I can put the idle anywhere I want and it holds. When I push back in on the pedal, it jumps back to 1100.
We had a slow afternoon today and I brought the car into the shop. I let it idle and reach it's temp, then threw some fender covers over the front of the car. It started to warm up and the idle droped to 900. I removed the covers and the engine cooled off again and the idle increased. (after a few min.)
The thermostst is weak/open.
I'm going to replace the 02 sensor just because it is old, and the PO was a big fan of cheep gas.
The TPS is working as advertised.