takes forever to idle down

calgarytracker · 10-28-2009, 02:01 AM

i recently picked up a well seasoned 92' geo tracker with a 3" lift and 31's. 5spd. its got 320000km on her and it runs great. 1.6 8v. i installed new plugs, cap, rotor. removed airbox for a cone filter. new catless 2" header back exhaust. i recently put in a new thermostat. ever since i bought it even in warm weather it would fire up and idle high (2000rpm) for what seemed to be forever it would eventually idle down and stay at about 1000rpm. i dont notice any obvious vacuum leaks and my temp gauge always shows pretty cold (right on the first notch after the cold mark) my heater works pretty quickly and i do live in canada so quick warmup and cold idle is essential.

i dug around looking at possible causes. i did my best to bleed all the air out of the cooling system as there is a large coolant passage under the thermostat for air to sit in. it doesn't warm up near as fast as my 5.0 mustang does even in cold temps. my idle will still be high (1500 or so) even tho i have heat already. its frustrating

i lowered my idle down a bit when it was warm by backing off the throttle stop

Bex · 10-28-2009, 05:30 AM

For what it's worth, my temperature gauge has never moved to warm, but always sits just a little past the C, no matter how long I've run the car. Like you, I have heat almost immediately. Although at first I thought this was annoying, now I just assume that this is normal for my car (this continued after new thermostat, radiator flush, etc.). My idle takes a good 5 minutes to shift from about 1500-2000 rpms, down to 850 (850 is normal). There are posts here regarding the ISC, vacuum leaks, etc., which would contribute to high idle:
Start with this one:
http://www.suzuki-forums.com/suzuki-...dle-speed.html
Also great info on The KickFix Repair Pages, for Sidekicks and Trackers.

CodyJ · 10-30-2009, 01:35 PM

IAC (guess above ISC?) Idle Air Control Valve. I have similiar problem.

I will trade you a IAC from junkyard for your 5.0 (/sarcasm). You can try adjusting, but go to the following pages above. Make sure your coolant lines are going were they should be to warm up the car, the heater works, right?

Richard Craneum · 10-30-2009, 01:56 PM

I am wondering if the engine is missing the T-Stat or is stuck open. Either way, the engine still cold and fooled the PCM that then engine is always cold keeping it on high idle. The PCM does not runs on a Timer to know when the engine is "cooked"

. The PCM lowers the idle based on Temp.

You better fix it right away, is not good to run it that way. Metal expands in a certain way and the engine was designed to run at its normal temp. The engine cylinder walls can stray "shrunken" and the Pistons will expand due to the burning of the fuel gauging the walls.

I have seen 5.0 Ford engines ran without a T-Stat in a tropical weather, even with that, the front Cylinder walls develop a Lip close to the chamber since the block heats at different rates (front cylinders runs colder that the rear ones, due to the entry point of colder water is at the front of the block).

Bex · 10-30-2009, 02:21 PM

Much of this is determined by the ECU, no? Is the CEL light on? Have you tried lifting codes from the ECU? Code 12 (ECU ok) or something else?

Richard Craneum · 10-30-2009, 02:24 PM

No, the PCM does not know the difference between a bad T-Stat and a good one. All it knows is the engine is hot or cold.

The temp sensor is like your hand on the engine, if you do not place your hand on it, you do not know if is cold or hor, just assume what is like for what you see.

In this case, the PCM sees the engine as cold. But does not have the common sense to say that is taking too long.

Bex · 10-30-2009, 02:52 PM

Quote:

Originally Posted by Richard Craneum

No, the PCM does not know the difference between a bad T-Stat and a good one. All it knows is the engine is hot or cold.

The temp sensor is like your hand on the engine, if you do not place your hand on it, you do not know if is cold or hor, just assume what is like for what you see.

In this case, the PCM sees the engine as cold. But does not have the common sense to say that is taking too long.

Don't know too much about this, but not sure I understand...he says that he has heat in the car. So wouldn't that be that thermostat working, car heating up, etc. Wouldn't that then point more to IAC (ISC), vacuum leak, bad sensor reading to the ECU, or something non-thermostat related? I don't give much credence to the temperature gauge not moving to the middle. Mine has never done that - always about 1/4 from the C when car is heated up.

Richard Craneum · 10-30-2009, 03:08 PM

The heater will get warm, but the water hitting the sensor is way colder that one that has been around the block.

One thing also, it could be a bad Temp Sensor. The PCM relies on that sensor to know if the engine is cold or not. Check the connections (clean, broken wires, tight, etc...), you could get one of those Infrared Thermometers and see if the water at the T-Stat housing is the right temp for the engine, or close to it. If that is the case, the Sensor is bad. If not the T-Stat is stuck open or missing.

calgarytracker · 10-30-2009, 03:18 PM

like i stated in my FIRST post. i installed a new thermostat and new coolant along with getting all the air out of the system. in -10c the heater works within a few minutes. even after the heater is hella warm...it still will be idling at about 1500 at that point. the thermostat opens and closes normally. how do i set the base idle? i pulled codes and i got a code 44 for miss adjusted iac? i did lower the idle down a bit..maybe this caused that code? my c.e.l is NOT on

Bex · 10-30-2009, 03:27 PM

Quote:

Originally Posted by calgarytracker

like i stated in my FIRST post. i installed a new thermostat and new coolant along with getting all the air out of the system. in -10c the heater works within a few minutes. even after the heater is hella warm...it still will be idling at about 1500 at that point. the thermostat opens and closes normally. how do i set the base idle? i pulled codes and i got a code 44 for miss adjusted iac? i did lower the idle down a bit..maybe this caused that code? my c.e.l is NOT on

Hmmm... this gets more confusing. No CEL light on, but ECU throwing codes? First, make sure that your CEL lamp works (should go on fora moment when you are starting the car. CEL lamp may not be working). Anyway, check out The KickFix Repair Pages, for Sidekicks and Trackers to see about adjusting IAC. In my FSM, code 44 is idle switch circuit (circuit open or misadjusted). It says that code 44 is set if ECU senses an open switch or circuit at idle conditions. Instructions are to remove TPS connector, apply vacuum to throttle opened, check resistance between TPS side harness terminals C and D. If reading is above 500 ohms, replace or adjust TPS. If between 0-500 ohms, reconnect TPS, remove ECU connector, check resistance between ECU connector terminals Y14 and Y24. Again, if above 500 ohms, check for faulty TPS connections (if ok, there is an open in the blue/white wire or grey/yellow wire). If between 0-500 ohms, you have faulty ECU cnnections or faulty ECU.
There, best I can do.