tfifeco

I am having a problem with my 1992 ES 300 - When the engine is cold whether its morning or any other time the engine will start but not hold an idle so it will die. I can start it and quickly give it gas and hold the gas pedal at about 1000 to 1500 RPMs for about 1 to 2 minute. Slowly let off the gas and it will then hold an idle and run perfectly fine from then on.

More info on recent work. THis car is new to me, bought it from an individual and had a lot of work done to it so i really dont have much history on the car.

Recently had all the plugs change, all the injectors tested and had 3 of the changed, and had the main ECM computer - all of this work was performed by a professional Auto Repair shop, not necessarily a certified Lexus shop but professional none the less.

I have done a little research and have learned there could be few things to look at but i am not really sure how the car is supposed to function if these things are faulty, what i am talking about is possibly

1.Cold Start Valve - how would car function if fautly? would it even start at all???
2. IAC Valve - Idle Air Control valve - how would car run if this is faulty
3. EGR valve - Ditto

What else would i need to look for?

And seriously, after the car warms up a bit for a couple minutes it run great, only caveat would be that it seems to idle only slightly low right at about 700 RPMS maybe a little under, also the check engine does come on after it has warmed and then a few more minutes go by of normal idle or drive ttime, the check engine light will come on but nothing seems to happen - continues to run great

Any thoughts to the Cold Start Problem???


thanks in advance

Hayk

iTrader: (1)

First of all, pull the CEL codes - that will give you a clue to what might be happening.

Try cleaning your IAC valve. It's attached onto the Throttle Body with two Philips head screws. At least that's how it is on my '98 and your engine should be very similar. If the valve is clogged up with carbon deposits, your car will not idle properly.

tfifeco

thanks thats a lot of help. how would i pull the codes?

tfifeco

Also, i am new to Lexus' - sounds pretty easy to remove the IAC valve, but is there a right / wrong way of cleaning it? i dont want to damage it in the process. i have already checked replacment price - dang expensive lol

Hayk

iTrader: (1)

Pulling the codes requires a scanner. The problem being is that your car is a '92. The car industry moved to a standard system across all brands in 1996, it's called the OBD2. The problem with cars that were made before 96 is that they all had their special system. I believe yours is known as OBD1. The easiest way would probably be to go to a mechanic or AutoZone (I'm not sure if autozone is able to scan non-OBD2 cars).

Hopefully some other members will chime in on how to scan the codes from the 2nd generation ES.
There is a lazy way and a thorough way of cleaning it..

The lazy way is to remove the rubber piping that goes to the throttle body and spray the TB and the IACV hole with some Carburetor Cleaner (don't use a Brake Cleaner, it's too harmful).

The proper way would be to unbolt the Throttle Body and then unscrew the IACV from the bottom of it. There is a risk of stripping or braking the screws because of how fragile they are. There is a member on here who had that issue. He ended up drilling out the remainder of the screws and replacing them with hex bolts. Obviously once the valve is removed, you can spray it down and clean all the gunk out.

Here is a video that might help you out.

Here is a guide that is very similar to our cars, except that it's from the later years when Lexus introduced VVTi and added an extra Throttle Body.

https://www.clublexus.com/forums/rx-...-write-up.html

tfifeco

thanks for the info and wow bit more invoilved than what i thought but i will give it a try.

also what about the COld Start Valve? is that something to consider?? or is this a valve where if it is fautly the car will not even start???

thanks again

tfifeco

Oh and a little more info to consider. When i had the Auto repair shop work on the car. A shop that i trust that does great work. the replaced injectors and a lot of other stuff. at the time i didnt really know as much as i know now so didnt take note to too much detail when they explained to me what they did.... BUT i do remember them exlplaining that they had the whole throttle body off and had ot clean up a lot of stuff that was corroded and had a lot of carbon buildup. Because i remember them saying this it may be safe say that they most likely already removed and cleaned up the IAC valve (i will call them tomorrow to see if i can confirm that) but i realize its an assumption at this point...if i assume at the moment the IAC valve has been cleaned up and functioning correctly what else could be causing this??? Any other thoughts?

thanks again

GS4_Fiend

iTrader: (22)

you can check for codes by shorting out pin TE1 and pin E1 and count the flashes. the DLC connector is under the hood on the left side of the engine near the strut mount i believe. Or you can google how to.

tfifeco

GS4_Fiend, thanks for the info, count the flashes where? what will be flashing.

But here is another question:

if the car runs great and idles fine after it warms up for literally only a couple minutes from cold start and seems to idle only slightly low ... around 700 RPMs ... but does not run or idle sluggishly at all at anytime. Would that rule out the IACV? or Not necessarily? In otherwords, if it were an IACV problem wouldnt the car idle/run sluggishly or bad even after it warms up?

thanks in advance

GS4_Fiend

iTrader: (22)

Idles around 700 is normal. If you got a bad IACV the idle will be erratic up and down. To check the codes. Just google, it has step by step procedure.

tfifeco

Ok cool, i will do a search to see what i can find. Now that you mention the irratic idling, when i first picked up the car from the auto repair shop the idle would fluctuate up and down by about 300 RPMs between about 500 to 800 RPM fluctuation. But becuase the Injectors and the Computer were bad the computer was sending way too much gas through the system to the point that liquid gas was coming out of the tail pipe, All of that was fixed and i even changed the Catalytic converter as a result. i thought that fluctuation was due to so much gas and over a short time it stopped. It doesnt really fluctuate like that anymore. So after watching the video in this thread and seeing what has been done already, Maybe it is the IACV - i am just hoping it not BAD to the point where i need to replace it. Is that possible? Can it bad where it needs to be replaced and still be able to run the way it does?

thanks for your help

GS4_Fiend

iTrader: (22)

Once you replace a new part or disconnect battery, computer is trying to relearn the adaptive memory. It will first run rough then will smooth out later. If you idle is low, below 700 rpms, i would check for vacuum leaks. But do retrieve the codes to aid in the diagnosing process.