87yota88

I have an 88 pickup 22re, that starts and then dies out after about 10 seconds. It started doing this about a month ago and i had swapped parts and tested lots, and then i drained all the gas out of the tank and refilled with fresh gas for no reason at all and it ran great for about 2 weeks then totally different symptoms. it would idle fine or you could hold the gas wide open with no throttle response in between. So i replaced and adjusted the TPS with factory toyota, no fix. then i swapped out the EFI relay, ECU, Circuit open relay, injectors/rail/regulator set from another 88 that i have, no fix. I then dropped the tank, and found two decent holes around the sending unit, and the return line was plugged, so i replaced the tank, sending unit, and pump, no fix. I have inspected the whole wiring harness and grounds all are perfect. I have also replaced the MAF with a few different ones from an 88 and still nothing. Now it will crank for awhile then fire up and after about 10 seconds it dies. I also found out yesterday that if i hold the MAF flap wide open it will start and idle fine but of course you cant give it gas or anything, it will just die. Also when it first started acting up, i replaced the distributor, coil, ignitor, plugs, wires,cap,rotor. no change. Really the only thing left to swap out is the wiring harness, which i have a couple laying around. I have been working on toyotas for the past 7 years and thats all i drive or own but this one just has me baffled. For some reason once it starts the fuel pump must be cutting out, which keeps me going back to the AFM, and open relay but maybe im missing something here? Any ideas?

thook

With all you've done component-wise, a harness issue sounds highly plausible. Swap out and see what difference it makes, unless you're up for testing at the ECU connector with a meter.

4Crawler

iTrader: (3)

Have you tried the fuel pump test jumper?
- http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

And any holes/cracks in the intake tubing, especially the rubber flex parts?
And any stored codes in the ECU?

87yota88

All hoses are good i had problems last year and had to replace the rubber intake tube section on the throttle body, but otherwise all rubber hoses(fuel, water, vacuum) were all replaced when the motor was rebuilt about a year and half ago. I was thinking about the codes i dont know why i didnt check yesterday but i will let ya know.

87yota88

Ok now im really confused. After all that i did, i finally figured i would swap out the wiring. As i was doing so i found 2 busted wires so i got excited. Still no fix. But still if you hold the AFM flap wide open it will fire up and idle like a champ, until you let go of the AFM then it will just sputter out. I tried the fuel pump jumper test and that did nothing. I also took another AFM (third one now) off my running 88 and tried that and still the same thing. O2 sensor is brand new, also i just went and got a TPS, and a new circuit open relay straight from toyota, adjusted it correctly but of course nothing. There is officially nothing left that i havent replaced or tested out. But i also just talked with a very good toyota tech, and he said to check out my ignition switch mainly the ST1 terminal, and to check for power at the fp term. and the +B terminal on the diagnostic box. The wiring harness by the way i just took out of another running 88 that im stripping.Any other ideas? Ohh yea and i didnt get any codes either.

thook

After you've done that, if you've had no success, I'll post a diagram for you to test voltage at the ECU. Or, you could PM ChefYota4x4. He's got the goods on that.

87yota88

problem solved. hooked up my inline fuel pressure tester and it was only reading out 20 psi and its supposed to be 35-38 so i blocked off the outlet end of the tester and the pressure jumped to 32 and held pressure once the key was off so i took off the regulator that i just replaced and it was shot you could blow right through it. Put a new reg. on and it turned over about 3 cranks and fired up and runs great now.