blue66tang

Hey guys, my nephew just recently got his license and bought a 87 4x4 with the 22re. Well the day he bought it and brought it home, it quit starting when it was warm. He has no idea what is wrong with it, so I have recently been trying to help him figure it out. So here are the symptoms: Starts great and runs great when it is cold. No issues what so ever. Let it warm up for just a few minutes, shut it down, and it wont restart till it is cooled down. However, it will roll start no problem. Fires off instantly when it is roll started and runs perfect after that. So I started messing with it, and discovered that the fuel pump is not coming on. When it is cool, I can hear it run for a few seconds and then shut off. However, when it is warm, it has no sound coming from the fuel pump. As soon as we can hear the fuel pump again, it will fire instantly and runs perfect.

I have been lurking around here the past few days, and have found nothing that resembles our problem to the T. So I decided to post. Any help would be great. He wants to drive his truck so bad, but cant unless he knows he can park on hills.

lostinafog

fuel pump sound oK
you have a weak battery, starter,or battery cables or a combination of them
the only diff in cranking it & roll start is you are not using any battery except to power fuel & ignition ECM must see 12volt or it won`t manage the engine must have sufficient amps to power the ignition.

angrybob

Look up cold start injector timing switch.

Use this to check it:
http://home.earthlink.net/~twopapa/toyefi.htm

TSB is here - Post #6
https://www.yotatech.com/forums/f116.../#post51771070

blue66tang

Hmm, I don't think it is battery related because he just put a new battery in it. However I will have him clean/replace anything that looks questionable.

It has something to do with the fuel pump i believe. Because as soon as we can hear the fuel pump run, it will start. Let it run for a few minutes, shut it off, turn the key on and the fuel pump wont run.

Doesn't the fuel pump get extra juice when the key is in the START position, as apposed to just the ON position. I would like to check that out too, but have no idea where anything is on this thing.

Can somebody post a picture with all the components circled. I am not familiar with these engines at all.

scope103

The fuel pump is powered through the Circuit Opening Relay. The Circuit Opening Relay closes when a) the key is turned to start (not run), OR b) air is flowing through the VAF (Volume AirFlow Meter) (when the engine is running).

This is easy to check. Jumper FP to B+ on the diagnostic connector. That will start the fuel pump when the key is turned to "on." If it starts then, your problem is in the COR circuit.

(Don't leave the jumper in there as a "fix." If you get in an accident that breaks a fuel line, the engine will stop but the fuel pump won't. That would be bad.)

snobdds

There is a VSV (vaccum switching valve) on top of the valve cover (blue) that runs froms the fuel pressure regulator and manifold vaccum that controls hot starts. It will lower or up the pressure in the fuel rail based upon if the engine is warm or not. The fuel believe it or not will turn to vapor in a hot engine, and this VSV will let the pressure off to turn it back into a liquid; thus allowing you to start the engine. Check to make sure it's working properly. Search on here or the FSM on how to do it...

Most hot starts are caused by this, but for some reason...it's lost on everyone.

blue66tang

Do you have a picture, sounds easy enough to look at.

snobdds

Well it basically looks like this



You basically blow air in the ports and air should come out the other side. There is also an Ohm test for the plug, but I do not know the numbers off hand. I'm sure there around here somewhere if you search.

blue66tang

Well I just tried the jumper wire from the +B to the FP and that does nothing. So I jumped it from the positive bat terminal to the FP and it starts right up. So somewhere between the Ignition and the COR it is not working. Where is the EFI main relay, and I cant seem to find the COR relay either. Is it behind the computer?

blue66tang

I think I may have traced the problem to the EFI main relay, under the fuse box.

Anybody know the diagram for the relay. I have been searching for a while, and am giving up. I can find lots of schematics but nothing that tells me what pins are what in the relay. I just want to bypass the relay when the truck wont start. That way I will know for sure that is the problem.

blue66tang

Found it!

It was the EFI main relay under the fuse box. I just kept tracing the fuel pump wires around till I landed at the relay. My nephew is pretty happy now. He had a good day. We finished up his truck, then hopped in and went a bought a dirt bike too. Now he is broke, but happy.