Chaviator

My 88 toyota 4runner when it's cold, winter, or in the morning in summer, it either does not start (winter) and if starts (summer/winter) does not want to stay on. I have tested, checked and cleaned: air intake, cold start sensor, air control valve, the sensor located after the air filter, forgot the name...all according to results are good...I do not know what else to do. I have to stay in the truck for a few minutes, at least 5, in order for it to stay on, on its own, very low idle almost stalling. Once it's warmed up, it has a good idle. If turned off and then on within one minute while warm, cranks very low idle like I just cold started it and I have to accelerate it in order to get back to normal idle again... Do any of you guys have had a situation like this? I have read similar issues, checked and tested what was recommended and still have the problem. Thank you in advance. I hope I can get this nightmare out of my way soon. I have dealt with it for the last 4 years...

coryc85

You should be able to pull the cold start injector out of the intake and see if it is pumping fuel. When cold, it should be dumping extra fuel into the engine to mix with the extra air coming from the idle air control valve being open. Are you certain that the idle air control valve is working properly? I had to replace mine (the tab inside was broken on the wheel). I checked the replacement by putting it in the freezer for like an hour and seeing that it opened up, then letting it warm back up and seeing that it closed. There is an adjustment for it also, which you can read about here: https://www.yotatech.com/forums/f128.../#post51643159


Some other things to check: EGR valve, I believe this should only open up when warm, but yours might be stuck open, you might also want to make sure your valves are properly adjusted, your TPS is adjusted, timing is set, and plugs and dist cap are fresh just to get yourself to a good baseline.

Chaviator

Thank you coryC85! I have checked and adjusted a lot of things. The cold start injector I had it out, passed the switch and sprayed fuel. Meaning the cold start timer switch and injector are good. I am doubting the IAC valve. I took it out, had a little carbon dust on it, cleaned it and put it back. Connected the battery and started it. Truck Did not stay on I had to press the gas until it warmed up. Now, I might take it out again and test it the way you did it. When I took it out, temperature 40 degrees F. the air passage was closed. I am thinking now if it is this cold it should be open right? Anyhow, I will put in the freezer and check what happens and also warm it up and see if there is any change. I did not check to find any adjusting screw any where. Let me know if you have any other thought. On sunday I will do this check up again and other things. The valves are good. I had to adjust the ones for the second cylinder, they where making my engine shake and no spark, but it is fine now...

Chaviator

I just looked and read the content of the link you suggested to read. I will definitely take it out again test the resistance and if it's good go ahead and adjust it to see if it works better. Thank you for the suggestions and the link, very helpful and make so much sense. I will keep the process posted.

Chaviator

Hey, i did what i could today, i think the iac valve is done. I took the part out. Adjusted the screw, reinstalled it. Cranked the truck and nothing. In order for it to start, i had to spray starting fluid in the air intake and then keep the gas pressed otherwise it was going to stall. Once warmed, it was good idle, but when i turned it off and start it again, the idle was very low, i had to play with the gas until it idled back normal...i will get the iac valve when i can because it costs too much and i cannot buy it at the moment. Let me know of any other idea. I assume that once i change this part, my starting problems get solved...???

coryc85

Yeah, sounds like your IACV is not working. Mine was actually broken inside. I traded a guy off ebay some other parts for a replacement. Since your's was closed at 40deg, I'd say it's definitely a problem. Find a replacement in the classifieds here or on ebay then go from there. You can also make sure your EGR is not stuck open, which would cause rough cold operation. Also make sure you have no vacuum leaks. There are also a couple of different temp sensors on the truck, 1 is for the gauge and does nothing other than operate the needle, the other sensor is actually for the ECU, so make sure that one is working. I believe the FSM has some tests for it.

Chaviator

Thank you for the suggestions. I gave up for now until i get the iacv replaced. In the mean time i will check the egr valve and other sensors to make sure their correct functionality. I will keep you posted with the progress. Once again, i trust that once i replace the iacv, my cold and rough start issues will get solved...thank you for your time and suggestions...!

Chaviator

I replaced the iacv and the truck still not start. I have to spray starting fluid to start it and once it starts the iacv does its work, I don't have to keep pressing the gas pedal for the truck to stay on. What else can I do...? Thanx!