Help starting issue! WARNING THIS TREAD HAS TECHNICAL DATA

Bad_Vision

Bad_Vision

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1987 4runner 22re EFI
plugs
wires
cap/rotor
ingnitor
coil
MAF Tested good
TPS Tested good and calibrated to 2.3KOHMS
COR Tested good
EFI fuse good
efi relay good
battery grounding is to .0045CUS

so with that said the truck will choose when it wants to start and if it does start it will die within 45 seconds of running.

now when i turn the key to start i can hear the COR click and the fuel pump start going, but when i turn the key off the efi relay will not turn off unless i tap it and my charge light and check engine light have a very light glow to them.
once i tap the efi relay on the fuse box with a screwdriver it then kicks off. i have tried 3 different relays all with the same effect.
now when it does start it runs great until i hit the gas then it bogs out and dies.

im thinking maybe bad ECU but the only other one i have is from my 85 and it doesn't have the same part number.
im out of ideas here guys and could use some fresh ones
 
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You mentioned battery grounds. did you check all the grounds ie. engine, body, frame?

The low dim idiot lights makes me lean towards a grounding issue or a short to ground.

Could be a wire issue too, since the efi relay did the same thing on 3 relays and tapping it always works. might have some bad wires in the junction block where the the relay plugs in.

electrical gremlins are the worst kind.
 
thanks for the reply nate.
umm yes i pulled the fuse box and the wire harness is immaculate looks brand new
now i thought the same thing about the grounds but i polished them all up and re connected them all engine body even the door frame one.
and yes gremlins suck the big one!
 
I'm with nate, its a short somewhere. Sounds intermittent, no wires crossing when the engine moves when you give it gas? Maybe an inside short of one of the relays? Automotive electrical isn't one of my strong suits.
 
ok so i looked for a ground fault by doing the continuity test on the harness only the grounding wires sounded the alarm. reference the FSM
 
Bad_Vision said:
ok so i looked for a ground fault by doing the continuity test on the harness only the grounding wires sounded the alarm. reference the FSM
Click to expand...

In this case I wouldnt do continuity but instead resistance. A DVOM might beep at you even if the ground is weak. Pull your cluster and check for voltage on both sides of those idiot lights. I honestly think something is back feeding through the ground side of some circuits. Now that you know that the main grounds are good, you might have some bad grounding points in the cab.

Chasing wires es muey bueno!

Pull it down to Missouri, I'll help you get to the bottom of it.
 
You can use your 85 ECU on your runner, 85-87 use the same stuff. Different part numbers because the 85's weren't very reliable. In 86 toyota changed some stuff around. As long as the 85 works then it's the exact same ecu as your 87. But, you cannot use the 88 or 89 ECU. You probably know this but toyota used different injectors in 88 and 89. The 88's are the same impedance but use a different plug, the 89's are a high impedance injector. Also, 88 and 89 use a o2 sensor heater as where the 85-87 do not.

As for the rest of your issues, I agree with the above. Sounds like a grounding issue. Pull your dash apart and check and double check your whole wiring harness throughout the dash and the body going all the way back to the tail gate. Make sure that your wire looms aren't chaffing on anything. The dash area especially because there's a lot of little screws, bends in the harness near metal brackets, etc, there that a wire harness could have been able to chaff on and ate through a ground wire. If it's a ground then it should be easy to identify as long as you can make good eye contact with your whole wire harness.

Good luck!

P.S.
No offense, but this thread isn't any more technical than any other thread that involves digging and troubleshooting. It's just another wtf thread :)
 
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right nate ill just pull it down to Leonard Wood from michigan i think i could buy another body for the cost of gas that would take....lol
maybe i should find one with a bad motor and swap it over.
 
SV_Dude said:
You can use your 85 ECU on your runner, 85-87 use the same stuff. Different part numbers because the 85's weren't very reliable. In 86 toyota changed some stuff around. As long as the 85 works then it's the exact same ecu as your 87. But, you cannot use the 88 or 89 ECU. You probably know this but toyota used different injectors in 88 and 89. The 88's are the same impedance but use a different plug, the 89's are a high impedance injector. Also, 88 and 89 use a o2 sensor heater as where the 85-87 do not.

As for the rest of your issues, I agree with the above. Sounds like a grounding issue. Pull your dash apart and check and double check your whole wiring harness throughout the dash and the body going all the way back to the tail gate. Make sure that your wire looms aren't chaffing on anything. The dash area especially because there's a lot of little screws, bends in the harness near metal brackets, etc, there that a wire harness could have been able to chaff on and ate through a ground wire. If it's a ground then it should be easy to identify as long as you can make good eye contact with your whole wire harness.

Good luck!

P.S.
No offense, but this thread isn't any more technical than any other thread that involves digging and troubleshooting. It's just another wtf thread :)
Click to expand...

the technical data thing is to fend off newbs who have not sufferd the joy of testing all there sensors lol

well im off to chase down a gremlin in my entire harness ill see you guys in 2 weeks, if i dont make it IROKE17 gets all my 4runner stuff but he will have to clean my dead body out of the dash.
 
That's B.S. I help you die and I don't get anything? Maybe I secretly want a 1st gen? Ungreatful...
 
lol nate i doubt you would want my truck its only 5inch lift not 12 inch and it has a 4banger not a v8.
besides spencer needs a straight axle you already have one.
i thought he would chime in by now guys its all yours then nate
 
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