High idle

[nickvash0104]

I just went out this morning to reset my ignition timing - found out that it was set to 5? instead of the normal 10? - and after resetting it, it was idling at ~1600 -- way too high. It was a solid 1600, but even after warming up, it still rested ~1000, 300 off from the standard 700. ISC? MAF? IAT Sensor? Or something I'm totally missing... I cleaned my ISC about 2 months ago, tested my MAF 1 month ago as well as my IAT sensor. O2 sensor is ~3 months old.

I couldn't find anything in the TSRM that dealt with a high idle; only rough / erratic, but mine is smooth. Ideas?

[rnoswal]

There should be an air screw on the front side of the intake manifold just right over the butterfly. Try screwing it in some and see if that helps. You might have knocked off a vacuum hose, but that amount of timing sounds like just a turn or so on that air screw should do it for you.


Russ

[suprra_girl]

did you do the ign timing with the diagnostic pins connected?

yea i would try vacuum leaks.... do you have an aftermarket boost gauge?

get some carby cleaner and spray around the intake and vacuum areas and see if your idle changes

if it does... you've found your leak

[nickvash0104]

Actually, I've got an NA No turbo here...

I'm fairly certain I have a leak somewhere along my intake as it's starting to crack around the lip of the angle tube - I'm still looking for a replacement aftermarket solution, but for NAs, there seems to be very little that has just the tube.

[suprra_girl]

ahhh k i'll reword it... if you had an aftermarket vacuum gauge you could see what your vacuum is at idle and you'd know straight away if you had a leak

if you have any cracks in piping between the afm and throttle body or intake manifold leaks or vacuum leaks this will screw with your idle

[rnoswal]

A possiblity until you find another tube is to put some silicone on the cracks. That will seal them up, plus remember the vacuum hose under the tbe that connects to the power steering pump. It is just a bit easier not being turbo charged in finding a leak, but there are a lot of vacuum hoses to check, so the spray is the easiest way to check it out. Even an open EGR valve will mess with the idle.


Russ

[nickvash0104]

I'm going to go w/ a compression test - too much work to play guessing games on my daily driver

I'm assuming a BHG will also distort idle... grabbed a test kit today, just waiting for the car to cool off so I can test it.

[rnoswal]

A blown head gasket will distort the idle in that it will cause a missfire as water or oil gets on the plug and fouls it out. An air leak of somesort is what will cause the higher idle speed. If you have an air leak in the tube anywhere before the butterfly valve then the idle will be lower because of not allowing the airflow meter vane to open like it should. Anywhere on or after the butterfly valve will cause the higher idle. I could be the cable that is not allowing the throttle to close all the way, or a gasket blown out somewhere along the intake.


It could even be your distributor. It may have come loose and is advanced too far. There are enough vacuum hoses to cause the higher idle and like the girl said, spray WD 40 around the intake and hoses, lightly, and see if the idle changes any. You could also get a stethescope and listen carefully and see if you can hear a place where air might be getting in unwanted. If you find a BHG, then never mind, as that has to be fixed first.

Even the idle speed control valve could go bad.

Russ

[nickvash0104]

Head gasket tested good

Now to investigate why else... I also flushed the heck out of my system, found a lot of rust deposits in there.

Going to re-wire the condenser fan so it's on all the time.

Anyone have any reccommendations for an electric fan to replace the clutch one? Also installation tips?

In regards to what I read in another thread, how effective is turning the heater on in regards to dumping heat? I bypassed my heater control valve so it helps it run slightly cooler, but not by much. Haven't tested the heating problems since testing the block / head and flushing / adding proper mix of coolant since it's 100+ outside and I just don't have the energy with my car having no A/C. As of today before the flush / test, idle was still high. Going to check my ISC again tomorrow.

[rnoswal]

A few guys have bought radiators from Fluidyne and have very good results. I bought an aftermarked race aluminum for mine and in the 100+ here, it never moves, even with the heater turned to 65. I bought the large 16" fan from Advanced Auto, all of the parts houses carry these things. I also have an adjustable temp sensor for the fan so I can dial in the temp I want it to go off and with this radiator it doesn't stay on long. Just take off the fan clutch and put four small bolts to hold the pulley and go with the electric fan.


The stupid thing about the heater core being used to help the engine cool is that it works!! That means running the heater in the summer to help it cool down. To me, that shows that the stock radiator is very inadequate. It is nice but very thin. Fine for up north I guess but not for down here in the south. Make sure the system is flushed and flowing very well, maybe even let the flush run through it a bit longer than the instructions state and do it several times.

Try water wetter too, it does help a little. I really think you have to have a piece of metal under the airdam to the frame under the radiator to keep the air flowing into the rad and not back out under the car first. Make sure the condensor is clear too. I didn't make a shroud for my electric fan and bigger radiator and it doesn't need one, but the stock radiator definately needs the shroud.

Well good luck with it.

Russ