Hey all,

I have had my 89 4Runner since I drove it off the lot in 89. Put a new short block in it 25k miles ago... cold weather of Jackson WY killed it and I oval'd a rod bearing. It has EFI.

The car has been running fine but recently started blowing blue smoke. So, I pulled the head, replaced the valve seals and put it back together. I also replaced the injectors while I had it apart. Now it will start but stalls after a min or so. I can't get it to idle until it is warmed up which means starting it multiple times. I can't get it to idle at 750. The idle screw is almost all the way out which sounds like a vacuum leak but I can't find one. Vacuum is at 15-17 so below spec but not by much and I think it's low because idle is low.

I went to the manual and the internet. I pulled the throttle body and cleaned it. I tested the ECU with a voltmeter, and it all checked out ok. I am now replacing parts.

What I have checked:

1. I adjusted the Throttle Position Sensor. It falls within specs.
2. Timing with T and E1 Jumper'd is at 5* BDC per specs. At 650 RPM, timing reads 12-13 so that seems right.
3. I checked the ECU with a voltmeter and it is within specs.
4. I set basic idle screw at zero touch plus 1/4 turn.
5. I verified all hose connections are routed correctly and replaced all with new.
6. I blocked off the ERG at the intake body so no exhaust is making it in.
7. PCV is checked and appears to be working. I have not replaced it but will if needed.
8. Fuel Pump works and runs when I move the AFM flapper.
9. Fuel filter was replaced 10k miles ago.
10. Fuel tank filter screen is whistle clean as is the tank itself oddly enough.

New parts:

• All vacuum hoses replaced and verified they are going where they should.
• Open Circuit Relay - New
• Main Relay - New
• Air Flow Meter - New
• Ox Sensor - New
• Idle Air Control Valve - New
• Fuel Injectors - New - not the cold start injector though
• Waiting on the Cold Start Timer sensor to arrive

Here are the symptoms:

1. It starts fine, idles at about 850 for about 1 min. then dies.
2. Start it again and it runs for a min or so, then dies. The warmer it gets, the longer it runs at barely 550-600.
3. It won't idle till it's warm.
4. Once warm, it won't idle above 650 even with the idle screw almost all the way out.
5. Reving the engine causes it to hesitate, then accelerate. Like the timing is not being advanced.

The one thing I noted was if I manually opened the air flow meter, it seemed to do better starting and staying running so I replaced the AFM. Still same problem.

To be honest, I am at my wits end here. I have tested and/or replaced everything I can think of. Hope someone with advanced knowledge has something to offer.

 

First go through the tests here: https://www.yotatech.com/forums/f116...-quits-312747/

I realize that you have changed most of the components already (AFM, COR, etc) but that link from scope103 also demonstrates how and where to check for continuity in some of the wiring.

 

I had this same problem with my Toyota it would run great during the warm weather. But as soon as it got cold it would take forever to start. Try the cold start injector. Do some research on it. Hope it helps

 

Agreed. I had the same issue on my 88. Malfunctioning cold start injector and same symptoms. Sometimes it would take a few attempts to start as well in cold weather despite nearly everything on the motor being brand new.

 

Hey all,
Thanks for the links and feedback. I tried something that I would never do with a V8... I advanced the timing by a lot... say 8* or so. It now starts and runs till it is warm and does not die.

WHY??? This is the most usual engine I have every worked on. Now that it runs, if I accelerate it TOO quickly, it bogs out and almost stalls. If I accelerate it slowly, it will rev up ok. Took it around the block and it did OK but on one corner, I rev'd it too fast and it almost died.

WTF is with this engine?!? It has never acted this way before. It was peppy and responsive. Now, it runs but I have to baby the throttle?

 

Timing chain off a tooth?
Distributor off a tooth?

 

I double checked the chain. While it wasn't perfectly straight up... it was really close. It like half a tooth off. I figure that's in the chain but heck, not bad right? Same with the distributor. I moved it a tooth forward and back and things got worse.

What is the mechanism that accelerates timing on throttle up? Is it the throttle position sensor? It seems that when the throttle advances slowly, the engine revs up fine. Quick throttle movement bogs it down.