jaredhicks

I have and 88 toyota pickup, 2.4L, 4WD, EFI 4 cylinder and it will crank over but only run for a couple seconds. i sprayed starting fluid into the intake and it ran as long as i sparyed the fluid then died again. I checked the fuses and relays and they arnt the issue. when we turn the IGN. to ACC. i can hear the fuel pump getting signal from the ECU. Looking for some useful/knowlegable advice as to what it is and how to test it. im thinking either ECU signal to Injectors, pump, filter, fuel air mix, air flow meter. now do fuel pumps go out just like that or is there at leased a warning to it failing. cause the truck started and ran one day and not the next. i did a valve adjustment and replaced the brake booster and hooked everything back up that we disconnected. can anyone help me.

scope103

1. "runs for a couple seconds then shuts off" is the classic sign of a problem in the VAF/COR circuit. The key powers the fuel pump in the "START" position, and a switch in the VAF closes the COR (Circuit Opening Relay) to maintain power to the pump. If the pump shuts down, it runs for a few seconds then stops.

2. BUT you say you can hear the pump getting signal in the "ACC" position. That is definitely not factory wiring (if you had an accident that broke a fuel line, the pump would keep spraying fuel until there was the fireball).

3. There is usually no warning when the fuel pump fails. It's an electric motor; when it stops it's dead. But they are very easy to test: jumper FP to B+ in the diagnostic connector (your '88 looks different from mine so you might need to consult the manual). With the key to "ON" you should be able to hear the pump running. If it starts and runs, you've determined it is a VAF/COR problem. If you can't hear it running, you either have no B+ bus (use a multimeter on the B+ terminal), a broken wire back to the pump (check at the pump) or a dead pump.

4. You said "I checked the fuses and relays and they arnt[sic] the issue." Sorry, broad statements like that always catch my ear. Which fuses, which relays, and how did you check them?

VAhunter

What I would do it unbolt the AFM from the airbox where you can see the square side and get to the flapper vane, turn the key on but don't crank. Push the vane open and listen for the pump to turn on, if it does not check your connections and do a resistance check on the AFM terminals, if you hear the pump that means the AFM is mostly fine, even if the pump is running it can still be bad, that's what was wrong with my truck, it would run but it wouldn't make the volume it needed to operate the engine. Also, you should be able to hear the Circuit Opening Relay click on when you start cranking and click off when you stop

Luvmeye22re

That's what my truck was doing last week right before it died. I'd start with the fuel pump test in the diagnostic port as scope mentioned. Easy to do with a paper clip and quickly rules out the pump. I just did my fuel pump yesterday. Good times!

jaredhicks

hey thanks for all the info. it helped alot. i was going to unbolt the intake to check the filter but i would rather test it the simple way first, instead of guess work.