I've been having a problem with my 85 4Runner this summer. On hot days, after it's run up to operating temperature and then shut down, it won't restart until the truck is completely cooled off. If I stop for gas, for example, I can't get it restarted.

I've been reading the archives here and on POR and haven't found anything that works yet. Here's what I've tried:

I have jumpered the fuel pump to make sure it's running and it is (thanks Roger Brown) - didn't help.
I have checked the fuel pressure at the Cold Start Injector - it's good.
I've confirmed that I have good spark.
I've played with the valve in the MAP to see if it's position makes a difference - it doesn't.

The spark plugs are not getting wet, so I am pretty sure I am not getting fuel past the fuel pressure regulator, but I am getting abundant fuel at the Cold Start Injector. I am still studying the FSM but I think that the pressure regulator is my problem, but I'd like to hear from someone that knows how to test these. Jim Brink, in an earlier message, said that if there is fuel in the vacuum line coming off the fuel pressure regulator then the regulator is bad, but there is no fuel present.

Could I be having a vapor lock problem here? Is it possible that my fuel pump is weak? I don't see how considering the volume of fuel shooting out of the Cold Start Injector when I crack it with the fuel pump running. Also, once it's started it runs fine and it starts fine cold.

Like I said, I need to continue churning through the FSM but I'd sure like to hear from you 22RE experts.

Thanks,

Allan

This was posted on a different toyota message board and might help...

http://bbs.off-road.com/ubbthreads/...&sb=5&o=&fpart=1

Are you absolutly sure its not getting fuel. Test the spark when its hot. Could be the ignitor.

Or it could happen to be something that happens as soon as the computer is out of the warm up loop.

If you figure it out, let me know. I have been dealing with it for 2 1/2 years. Checked everything out including fuel pressure check. It starts fine when cold but I have to crank about 5 - 10 seconds when it is warm. I always carry a spare starter 'cause I know I abuse it.

Unless Im mistaken, the injectors used in your EFI system are connected to a resistor (I think thats what it is) mounted on the passenger inner fender of the engine compartment. Might be that its being effected by the heat and not transmitting the right voltage to the injectors. You could have all the fuel pressure in the world in the fuel rail but if the injectors cant hear the ECU calling...they aint gonna spit any up. This would also account for why there is pressure to the CSI yet dry cylinders. Next chance you get have someone help you out. Get it to duplicate the problem and when trying to restart it, check the voltage at the injectors electrical plug and see if there is current. Other than that...things get more complicated. Also check the wiring harness for damage like worn/burned insulation or abmormal bends like 180's.
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

You might also check the VSV (vacuum switching valve) on the back of the valve cover that runs to the fuel pressure regulator. One "theory" I heard for its function is to help with hot starts, by upping the fuel pressure while starting. Not sure I believe that theory, but it was from a fairly reliable source. I actually have mine disconnected (bypassed) and starting doesn't seem to be affected and the engine accelerates a bit smoother.

Thanks for the replies. I have a new twist to this now. I went out this afternoon to try and start it after it had been sitting in the hot garage all afternoon (around 90 degrees) and it won't start. It hasn't been run it two days so it appears to be an issue with temperature so I'll have to consider that.

I'm going to start going through all the checks in the FSM and see what I come up with.

Thanks again and I'll post if I find the problem,

Allan

I hope you mean "When" you find the problem...

I killed the starter motor in my 4Runner trying to troubleshoot this problem. After I replaced it (lifetime warranty Autozone part) it seems to be starting fine, hot or cold. I also put new NGK plugs in as I had fouled the old Autolites pretty badly messing with it.

I think the plugs made some difference but I noticed also that the new starter turns the engine over more quickly than the old one. I wonder if the engine has to be cranking at a certain speed to make the AFM work properly? I'll have to look into it some more.

I haven't thoroughly tested it yet on a hot day so I'll post if I find anything else out.

Allan

I wanted to update this as I finally cured my starting problems.

In my last post, I said that a new starter and plugs seemed to help. Wrong. It has been acting up all through the fall and early winter. However, my head gasket started to leak (coolant coming out between block and head). I have had a head gasket problem for a long time now (low compression, slight coolant loss, overheating) but I wasn't absolutely sure so I didn't want to pull the top end apart until I was.

Anyway, I did a top end rebuild and it starts easily now with no gas pedal. I believe that my starting problem was related to low compression, caused by a leaking head gasket. I used a McCord gasket set with a graphite head gasket which needs to see the engine warmed up to operating temperature before it will seat and seal. I had a very hard time getting the truck to start after buttoning up the top end so I checked the compression and it was very low. I finally (after killing another starter) got it to start and now that the gasket has seated/sealed, it starts hot or cold easily.

I hope this helps someone else out if they are searching this forum for starting problems/solutions.

Allan Davis