85 Camry idles rough, above 1800RPM fine??

[LyleD]

I am having trouble getting this car to idle. It started one morning after running fine the night before. I have changed the plugs, fuel filter, distributor cap and rotor. The wires show good unsing and ohm meter and were changed about 2 years ago. I removed the throttle body and cleaned every port on it. I pulled off an almost completly plugged EGR valve and cleaned it out. I have checked for vacumn leaks and replaced and repaired the hoses as needed. I am tired of spending money to no avail here. The car is tired as it has 220,000 miles but I have never failed to keep it running until now! It shakes bad once in gear, its an automatic, until it gets up to about 1800 RPM. If you floor it, it will take right off. Once you slow to about 45 MPH, it is in the low RPM range and starts to shake again. I have a Chilton manual for the car and I am pretty sure it has to be in the idle area for a problem. The manual talks about an Idle Air Control valve, or an Idle Speed Control valve, or an Air valve. My engine is the 2SE. Does anyone know where this valve is located? My book states to remove the two bolts and extract the valve from the cylinder head rear cover but not a picture for the 2SE?? Since I have been all over the engine and still can not find this valve on the back, front, sides or even under the intake?? The only valves on the back are the EGR and EGR modulator. Any help before I run it over a cliff???? Thanks in advance.
Lyle Pfeifer

[Mike Gerber]

Most idle air control valves are located at the base of the throttle body. Not absolutely positive about the 2SE engine, since it's been a while since I owned one. There is usually a square or diamond shaped port in the base of the throttle body that leads to the idle air control valve. If there is one, spray throttle body cleaner or O2 safe carb cleaner liberally in to that port. Let it soak about 10 minutes and then put everything back together and start the engine. It will be a bit rough to start, but it eventually will start. Drive it around for about 10 minutes to clear all the cleaner out and to see if the problem is resolved. If not you may have to remove the idle air control valve from the throttle body and clean it that way. Removal of the throttle body will require a new gasket when it is reinstalled. I hope you did that the first time you removed it.

If that doesn't solve your problem I would next do a compression check. You could be chasing a miss from a cylinder with low compression. If the compression checks out OK, then check the throttle position sensor (just a hunch here since you said "If you floor it, it will take right off". Next check the coil inside the distributor and the O2 sensor.

Good luck.

Mike

[LyleD]

I saw the port on the bottom of the throttle body and it is clean and I did make a new gasket for it. I was looking for a separate motor/valve as Auto Zone has one for $200 but I cannot seem to find it anywhere at least not on my throttle body. I will check compression but it seems to run fine above 1800 RPM. It is burning a little oil as it is getting passed the valve guides. Thanks for a few more ideas as I refuse to give up.
Lyle

[Mike Gerber]

"I saw the port on the bottom of the throttle body and it is clean"

Did you spray the cleaner liberally in to that hole and let it soak, or possibly clean the idle air control valve itself when the throttle body was off the car?

Mike

[LyleD]

Mike, that port is before the butterfly or valve in the throttle body. When I sprayed the cleaner into it, it came out the top through another hole. Compared to the EGR valve, this was open. The hole in the EGR valve was probable about the size of a neddle, closed off by carbon build up. I never seen one so bad, but its clean now. Is there any vacumn connected to the transmission on this car? I just wish it would throw out an engine code or something!
Lyle

[Mike Gerber]

"Is there any vacumn connected to the transmission on this car?"

I don't believe so.

Mike

[LyleD]

Mike or anyone else, are the fuel injectors a 2 stage injector? One port at idle and another at normal power? I have narrowed this down to cylinder 1. I bought new leads today and put them on. The number 1 cylinder does not run any different with the lead on or off. I pulled the plug and its firing but not dirty or browned at all since I just put those in too! It still runs fine above 1800 RPM, but not at idle. I even ran it with the plug out and other than rough all the way, it ran. I did a compression check on 1 and its low, around 85, but 220000 miles might have something to do with that.
Lyle

[Mike Gerber]

"I did a compression check on 1 and its low, around 85"

Did you do the compression check with the engine at operating temperature and with the throttle fully open? If so, you did it correctly and have found your problem. That cylinder has very low compression. Normal compression for the 2SE engine is 171 PSI. Minimum compression for each cylinder is 128 PSI with only a 14 PSI difference between each cylinder. To determine whether it is a worn piston ring/cylinder bore problem or a valve or head gasket problem, pour a tablespoon of oil in to that (or any other low cylinder) and repeat the test. If the compression reading goes up with the oil added to the cylinder, you have a piston ring or cylinder bore problem. If not, the problem is in the valves or the head gasket.

Good luck.

Mike