Warm start problem

[tomzapf]

I have a 2000 4Runner Limited 4x4 with about 110 k on it. It always has been running perfect and I treat it like my baby.
Recently about a month ago I noticed that it has trouble starting when its warm, lets say I drove for a while parked and turned the engine off for few minutes and try to start it back up, it turns perfect (I don't think its a starter problem) but the rpms go down and it dies out even sometimes. I then have to press the gass pedal to keep it alive for that second, and then its fine.
Timing belt has been changed, regularly maintained and tempered. Cleaned out the MAF sensor, replaced O2 sensor and cleaned out throttle body. Still same issue, I would appreciate any responses

 

[Sams984Runner]

hey there buddy, i can understand your frustration. b4 i got my T4R, i had a 96 Nissan Maxima and they are famous for this problem, on maxima's forum many people had the same problem with no solution. I took to different places and got different answers, like ignition coil, switch, etc. but nothing really made sense. For a while i kept thinking that the second pair of relays behind my ignition switch was the problem, but i didn't bother touching it. I ended up putting a push start button to direct connect the starter.

What i would suggest(that u already know) is that to get it checked by the Dealer. Do not waste time going to these other car care places, they'll just charge you and won't help @ all.

Good luck:driving:

 

[tomzapf]

Hey, thanks for the reply man, yeah thats what I was afraid of. I think I'll mention something at my next oil change and they might give it a look. Of course my dealership charges like a 100 dollar inspection fee, which then is included in parts/labor if it comes down to the repair. Hopefully I can find a quick and easy solution which won't be too $$$

 

[JP4RNR]

I would try checking and cleaning of the MAF sensor

 

[tomzapf]

If you read my first post thats already something I've done, didn't help although its running much smoother and check engine light is gone - maf sensor but this wasn't the problem with the warm start deal.

 

[jwyshrek]

How warm?

Don't know if this will help, but on 97-01 XJ Cherokees (Jeep)...a TSB was issued for a problem similar to what you describe...Hard Start after Hot Soak...due to vapor lock within the fuel injectors. The solution is to wrap them with heat shield cloth...

good luck...

 

[Sams984Runner]

How about that...

I was discussing this issue with my big b last night and told me some really interesting points that could cause this to happen.

When we start a cold engine, the fuel pump pumps fuel in to the pistons for the engine to start. Now, when the engine is already warm and you try to restart it, the fuel pump is not suppose to pump any extra fuel in to the pistons, because it is already warm and don't need extra fuel to spark. But, if the fuel pump is not acting right, it WILL pump some more fuel in the engine causing the Pistons to be "Flooded". In this case the engine will refuse to start instantly.

It could be other reasons for that to happen, the Computer may be malfunctioning etc. But i would get my fuel pump checked and replaced if necessary.

Again, good luck with that bro. keep us posted

 

[tomzapf]

From talking to other members here, I think I figured out what the problem is: dirty IAC valve
Underneath Throttle body

Anyone wants to second that before I start working on that?

 

[GSGALLANT]

From talking to other members here, I think I figured out what the problem is: dirty IAC valve
Underneath Throttle body

Anyone wants to second that before I start working on that?

I've already suggested that in your other thread. You shouldn't double post threads for the same problem, by the way.

 

[tomzapf]

Sorry for double posting, my mistake.
As far as the dirty IAC valve goes, I'm almost certain that its my problem from reading other members' problem being exactly the same as mine. I'll try cleaning it this weekend or the following and will let you know if it worked. Thanks much!

 

[97hb]

If the iacv is dirty then you should be able to idle with the pedal. There is a screen in the iacv that can get clogged, just unbolt and hit it up with a lot of brake/carb cleaner and it should be good. It also sounds like it could be your fuel pump relay, or this is a problem known to hondas.

 

[tomzapf]

Must be the new Hondas, I owned two hondas before the 4runner both in the high 200k when I sold them and never had that issue. I still hope its the IAC valve

 

[Techninja]

Have the same problem: Bought mine last Friday

136400k; Carfax says:
Maintenance inspection completed Front brakes replaced
State emissions inspection completed
Automatic transmission fluid and filter changed Oil and filter changed Air filter replaced Wiper(s) replaced
Fuel system cleaned/serviced

Although there is no way of knowing. Not a Toyota dealer...

I'm going to check with my new code reader and see if that reveals anything...

I barely have to touch the throttle to start when warm.

Runs great after it starts.
Got 21 MPG combined driving

 

[cstraface]

Has anyone found a fix to the low RPM on warm start problem? There's a bunch of threads discussing the issue but I can't find anyone reporting back a conclusive answer. I realize it's case by case, but still curious if there are any commonalities...anyone?

 

[heston83]

Heat Soak in T4R

Pilots know the answer to this, but we don't have the right equipment to easily fix the problem in cars...

Heat soaks the fuel lines and causes bubbles to form. Since engines dont run on bubbles, this causes starting difficulty. In complex piston aircraft, you can just set the mixture to full rich and run the aux fuel pump for a few seconds to flush fresh fuel into the system, flood the cylinder, then do a standard flooded start procedure and you're done.

Since we cant do that in a car, unfortunately, I think that either wrapping the fuel lines in insulation, and/or adding auxiliary ventilation may be the best way to go.

*fingers crossed* This is the solution I'm implementing soon on my 96 T4R that's experiencing the same hot-start issue.

 

[Vizenis]

I had this same issue on a '97. After the engine got hot, it would not re-start until it sat for a while. Turns out it was the coolant temp sensor. Replaced it and never had the problem again.

 

[Jason_nakal]

Thanks - I had that thought. It’s a cheap sensor, I’ll go ahead and change it.