2200 RPM + idle. Need some suggestions

[Okayplayer]

Hey all, I'm changing my thermostat and I'm pretty sure that it is in there incorrectly, what is the proper orientation for the thermostat? I know it's spring side down, but what about the direction it should be clocked in?

 

[Brunoboy]

i twist mine clockwise til it doesnt move anymore.

 

[Okayplayer]

Okay, I see how that can work... can anybody second this? Just want to be sure....

 

[Diego]

Shane has it right. Look at your thermostat, notice the "pin" that pin goes into the "hook" part of the housing... when you look at it you will see the ONLY way to put it in, correctly.

 

[DR1665]

Just swapped in the "winter" tstat this past weekend. Right or wrong, when I pulled the housing, the 170°F tstat had the little jiggly-bit at 12 o'clock, so that's how the 190°F went in. It works. (And I got my heater back on the highway below 70°F ambient!)

 

[Okayplayer]

Got the tstat in there with no prob, thanks for the help. I got the car warmed up and now this sucker wants to idle at 2700 rpm. WTF?!?! I checked around and I couldnt find any boost leaks. Any thoughts? (yes I'm thread jacking myself) Should I open up yet another high idle thread, or can someone point me in the right direction?

 

[FlyingEagle]

Wonder if you have an air pocket in the TB. Must have jostled something in there. These TB's usually high idle with leaks though...

 

[DR1665]

How healthy is the wire harness connected to the water neck, there, chief? They tend to get brittle and crack. I'm pretty sure one of those sensors there feeds the ECU coolant temp data, so if it got munched in the re-assembly, there's a chance the ECU thinks it's -45° or something and is playing ISC games.

You did burp the system, though, right? Start it cold with the radiator cap off, let it idle until up to temp with the heater running full blast, add coolant as necessary to maintain the level, pretty much wait for the bubbles to stop?

 

[Okayplayer]

So I ensured the coolant system was burped and the idle is still sky high. I did however discover my bov is leaking terribly. Could this cause high idle?

 

I spent some time looking at Dez's car last night.

Very weird problem.

The car runs about 1400-1500 rpm at cold start up. Then, as the coolant starts flowing, the revs increase slowly until settling near 2000 rpm.

Fuel pressure is 38-39.

Maf (1G) is good. Ecu recognizes (MIL comes on) when it is unplugged, also when it is still plugged in, but not attached to the intake pipe. We also swapped in a known good, same result.

Swapped in a good ecu, but Dez's car has a 1990 board, so the wiring has been swapped, so we couldn't trust the outcome. If it is worth anything, the idle did drop (to about 1100-1400), but was hunting very badly. During this, the throttle open/closed switch was unplugged, and the idle went high (2000-2100) and smoothed out. Plugged back in, idle dropped and hunting again.

Boost leak test proved that there is a sizeable leak between the turbo outlet (j-pipe) and the turbo. The leak is bad enough that we were unable to determine if there are others. Seeing as how this is post-maf, pre-throttle body, it seems as this leak should cause the car to want to die, not idle up.

The ECT wiring is good, don't know about the ECT though. When the ECT gets unplugged, the MIL illuminates.

I don't know if the TPS adjust or base timing is correct, but neither should affect idle this much.

The throttle body is suspect particularly because the BISS port has been filled with silicone. Obviously a problem, but the same TB was in place before the high idle developed. The ISC is likely no good as well, it is an original, not the black plastic one, and most of the 1st rendition units have sh*t the bed by now.

CAS is good. The car runs.

I am stumped.

 

[GSX_TC]

I had this EXACT symptom on mine a few months ago, I sent my throttle body to Steve Monroe over at throttlebodys.com and rebuilt it with all the bells and whistles and fixed my problem.

I'll post the video of it later so u can see how similar it was to what Your describing.

 

[GSX_TC]

ok here's the video click this is how my idle used to be before i sent it off to Steve Monroe.

 

[Okayplayer]

Hey mike, that is pretty much the exactly what my car is doing. I think that I will swap out the isc to see if that helps at all. I still think that it maybe a problem with my ecu as it does need a bit of work. I posted up pics of the leaking caps and that might be frying my isc. I know that there are a few people local that should be able to fixit up for me, but maybe it will help with changing to a known good one.

 

[GSX_TC]

Do 3 things to be sure to get rid of that problem like I did. 1. Replace ISC 2. Send throttle body to get rebuilt and 3. Send your ECU to Terry Posten to have the ECU's caps replaced and have the ISC drivers checked.

 

[desant78]

Go to vfaq . Make sure isc is in proper ohm spec. Fix the leak...if its a j pipe shouldn't take long. I'd focus in the TB last since it will cost the most. Is engine coolant reading propr via data logger? Also will cause similar problems in my experience.

 

[asmo]

Had a simmialr problem with mine, Id check the ISC, look on youtube, search dsm isc. theres a guy who shows how to test it and makes it pretty simple to understand. a bad one could ruin the ecu if its not fixed.