rockrider

I just recently went through and rebuilt the 22re in my 88 4runner and ive been having a problem with a sputter in the upper rpms under load. I assumed fuel so in the last couple weeks ive replaced the fuel filter, fuel pump, injectors, and ive used compressed air to blow out the lines. its now getting no fuel when I attempt a start up when at operating temperature. im at a loss because I am getting spark and I am getting fuel pressure when cold. could I be losing a signal somewhere on the way to the ecm? or could my icm be going bad? I have no codes.

scope103

Welcome to YotaTech.
What do you mean "no fuel"? First, jumper FP to B+ (this forces the fuel pump to run with key-on, bypassing the VAF-COR circuit) (4crawler has pictures to help you find that connector on a vehicle of your vintage https://www.4crawler.com/4x4/CheapTricks/index.shtml) Does it start reliably now? That points to a heat-sensitive problem with the VAF or COR (the COR is probably a little more heat sensitive, but don't over-react. It's very reliable.)

If that doesn't fix the problem, look closer. Replace the fuel return line from the FPR with a clear vinyl (6mm / 1/4") line to a suitable container. Start the fuel pump with your jumper (don't start the engine). I get about 1/2 liter/min on my 3VZE. If you get nothing through the return line, the pump is not running, or not producing enough pressure to bring up the FPR.

Note that none of this has anything to do with the ECM. The ECM will open the injectors (for instance), but has nothing to do with fuel pressure.

rockrider

what I mean by no fuel is I will crank the starter for around 15 to 30 seconds after driving the truck around and I smell no fuel and the spark plugs are dry when I pull them. I assumed I was getting no fuel in the cylinders. I also cannot hear the fuel pump engage when the engine is hot.

rockrider

it starts perfectly when cold. which is why I assumed it was a computer or module. if you don't mind my asking, what Is the COR? im not savvy to all the acronyms yet. thank you.

scope103

Read the 4crawler article I cited to; he does a good job of explaining this.

Particularly, you SHOULDN'T hear the fuel pump. It doesn't start until you turn the key to STArt, at which point you won't be able to hear the pump over the starter.

Based on your description, it's possibly you have plenty of fuel pressure, but (for instance) the injectors aren't opening. Or the spark plugs aren't firing.

But ... if you do the tests I described you will be MUCH closer to a good diagnosis.

rockrider

I did the first test you described and it did not fix the startup issue. I then tested the fuel pressure and I had a strong flow through the return port but I did not have an accurate way to measure how much I got on hand but I filled a 16 oz water bottle in about half a minute maybe less. I went ahead and did the tests on the MAF and got good readings on all of the static tests. but on the first running test between pins E1 and Fc I got a reading of .3 when it should have been an open circuit. could I attribute my problems to the maf sensor?

EDIT my mistake I misread the test im going to look at it again
the reading when the flap is open is still .3 when shut and jumps to 50 plus at one place in the range but should read out as infinite could that be causing my no start and or other issues?

scope103

.3 miles/gallon? .3°?

Do you have the FSM? I can't imagine trying to do an engine rebuild without it, but I suppose people try it. After all, you DON'T have a maf [mass air flow] sensor. Here's the FSM (for a '93) on testing the VAF http://web.archive.org/web/201209071...33volumeai.pdf

Guessing that your .3 is 0.3 ohms WITH THE FLAP OPEN, that is (close enough to) correct. It should be infinite when closed. But that isn't your problem; you have plenty of fuel flow (I assume you ran the flow test when the vehicle would not start.)

While you could have a problem with the injectors not opening, a much more likely issue (and one much easier to check) is the ignition timing being way off. Do you know how to check it?

rockrider

that is an almost identical spec sheet to the one I have. I just misunderstood the first dynamic test. I use the term MAF out of habit I apologize for not being exact. I appreciate your help. Ive done several rebuilds and I did have a manual with all of the specs every time. I have checked the timing several times with the jumper in the correct pinholes. I have also taken it to a shop that I was previously employed at and they also checked the timing. when it is running it runs smooth so I don't see any reason for it to be far enough out that it does not fire. ive also checked the valve lash when cold to ensure that I was within tolerances still. I really do appreciate your help I am at a total loss at this point on what could be wrong.

scope103

Well, you've confirmed fuel pressure (technically, you've only confirmed enough pressure to open the FPR, but the FPR isn't likely to be THAT temperature sensitive). Have you used the inductive lead on your timing light to confirm spark on each cylinder when warm? If you have spark and fuel to the rail, that points next to the injectors. You can use a "noid" light to confirm that the injectors are getting pulse (all four injectors open at once, so you really only need to test one. Either a commercial noid light, or make-your-own with a 12v led. ) The injectors have 12v all the time, and are opened by the ecm grounding the other side.