High Idle & Overheating
 

'93 R1, Koyo Radiator, Stock ECU, DP, Exhaust, CAI box. (I haven't done any work since the car was running normal.)

I have a temp sensor tapped into the hose between the thermostat and the AST. Just the other day, this hose burst where I had tapped it and sprayed coolant all over the "intercooler cavity." I fixed the hose and filled the engine (at the thermostat cap) with 60/50 water/coolant mix.

Now, when I start my car (and after a throttle blip to disable the AWS), it idles high, usually around 2000 rpms. After driving the car and getting it up to normal operating temp, the idle does not drop. Unfortunately, this is not the worst of my problem. Even though the engine seems to have full power, and the boost gauge shows full boost, the engine begins to overheat after about 10 minutes of normal driving. I verified that the passenger-side fan spins by grounding the low-speed fan relay (note: I haven't verified that the fan comes on during driving). I have checked that there is sufficient coolant in the overflow tank. After driving the car, there are no noticeable coolant leaks (or any leaks for that matter). Nothing sounds different, aside from the high idle speed.

Do you have any ideas why my car is overheating and idling high? Could it be that the wp-alt belt was sprayed with lots of coolant and is now slipping? Doesn't the ecu rev the engine to try to promote hot-coolant circulation? What about air in the coolant [passages]? Could a bad thermostat cause this? Could a piece of the busted hose gotten into the coolant passages (and would that make any difference)? *Any* ideas?? I'd appreciate any help. Thanks!

Did you burp your system properly?

You should verify if your fans are coming on when they are supposed to. They should come on at just over 220 degrees. 220 is not overheating.

I have not squeezed the radiator hose, but I have refilled the filler neck. However, I have tested the car a couple times with the same results. Even if I didn't burp at all, it shouldn't be overheating after 10 minutes, some people drive there cars to burp. I'll go make sure the engine won't take anymore fluid.

I don't have an aftermarket temp gauge anymore...so I can't check the temp...but I will make sure they come on at some point.

Alright, tried the squeeze-lower-radiator-hose trick and burped the system much better. I then refilled at the filler (thermostat). During the burping, it seemed like I was pushing fluid back into the reservoir.

I also checked to make sure the fans were coming on. I did verify that the passenger side fan is coming on when the car gets up to temp, but I wasn't able to check if the driver side fan is coming on.

After these, I test drove the car and it began to overheat again. It was also reving at around 1500. I shut off the car and let the fan run to let it cool. After about 30 minutes of cooling, I tried driving it again. This time it was reving normally, but the stock temp gauge began to climb past 1/2 so I turned the car off and let it cool. Both times, I had the heater on full blast. I guess, unfortunately, it wasn't a burping problem.

Anyone have any other ideas?? Could a broken or stuck thermostat be the culprit? How do I test it? What about a broken or whacky temp sensor? Could a broken temp sensor affect idle speed? Interestingly, the engine bay didn't seem excessively hot, like the temp gauge was suggesting the engine was. However, if it was a temp sensor, why would the gauge seem to work correctly (i.e. moves linearly, intelligently)? Again, I'd appreciate any help!! Thank you very much!!!

^^^ bump for help, please :)

^^^ bump for help, please :)

^^^ bump for help, please :)

^^^ bump for help, please :)

aagghh!! site gave me no response, so I submitted multiple times. Sorry, didn't mean to bump that many times!

if u have burp your system correctly..it's either the sensor or coolant seal.. trace the temp wire to see if any damage

if you dont got the fans goign when your car is warmed up to 180 degrees, there is your problem. why have some people not dont teh fan mod??? turn them on, their there for a reason people! as far as your high idle, have you tried to lower it via the adjustment screws? try unplugging everythign to do with the idle system

had a similar problem when i bought the car... Lower intake gasket was leaking... changed the gasket.. Idle came to 750 rpms and heating gone...

Check the upper and lower intake gaskets...

I hope this helps