2000 3.4 from a 4runner wont start. Help
10-29-2021, 09:36 PM
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2000 3.4 from a 4runner wont start. Help
3.4 swaped pickup has ran fine without issue for the last two years. Monday this week it wouldnt start in the am after hunting all weekend.
fuel pump wasnt working so i droped the tanks and replaced it only to have it not start afterwards.
things i have checked/noticed
Spark, is good.
fuel pressure is good
All fuses and relays are good
I have re grounded everything
All wiring seams to be good
check engine light isnt on untill after you start cranking
Will run if i spray starter fluid, but dies immediately after i stop
After cranking for like 30 seconds plugs are dry
i called the manufacturer of the swap harness and they gave me a list of diagnostic checks to run. and senD the results back to them.
Basicaly they said seamed like the ecu is fried.
Seam like thats plausible to me, i just want to see if anyone else had any ideas before i buy a used ecu as they are pricey. And i dont have time to wait on a repair because this is the wifes daily.
fuel pump wasnt working so i droped the tanks and replaced it only to have it not start afterwards.
things i have checked/noticed
Spark, is good.
fuel pressure is good
All fuses and relays are good
I have re grounded everything
All wiring seams to be good
check engine light isnt on untill after you start cranking
Will run if i spray starter fluid, but dies immediately after i stop
After cranking for like 30 seconds plugs are dry
i called the manufacturer of the swap harness and they gave me a list of diagnostic checks to run. and senD the results back to them.
Basicaly they said seamed like the ecu is fried.
Seam like thats plausible to me, i just want to see if anyone else had any ideas before i buy a used ecu as they are pricey. And i dont have time to wait on a repair because this is the wifes daily.
10-30-2021, 01:46 PM
#2
Registered User
Did you check the COR? That's what it sounds like to me. To ME.
Have you tried shorting the Fp to B+ connectors in the little test jack on the side of the engine compartment fuse block? If you jumper them, and you can hear the fuel pump running, will it start?
CAUTION: DO NOT drive it using the jumper. Major fire danger if there's an accident.
If it'll start and idle with the jumper in, it's either the COR or ECM. Both under passenger side kick panel. Try the COR first, it's a lot cheaper
Have you checked the efi fuse and relay? The IGN fuse? The AM2 side of the key switch?
I apologize if you've checked all these goodies already, I'm just trying to think of any possibility I can.
Good luck!
Pat☺
Have you tried shorting the Fp to B+ connectors in the little test jack on the side of the engine compartment fuse block? If you jumper them, and you can hear the fuel pump running, will it start?
CAUTION: DO NOT drive it using the jumper. Major fire danger if there's an accident.
If it'll start and idle with the jumper in, it's either the COR or ECM. Both under passenger side kick panel. Try the COR first, it's a lot cheaper
Have you checked the efi fuse and relay? The IGN fuse? The AM2 side of the key switch?
I apologize if you've checked all these goodies already, I'm just trying to think of any possibility I can.
Good luck!
Pat☺
10-30-2021, 06:22 PM
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Did you check the COR? That's what it sounds like to me. To ME.
Have you tried shorting the Fp to B+ connectors in the little test jack on the side of the engine compartment fuse block? If you jumper them, and you can hear the fuel pump running, will it start?
CAUTION: DO NOT drive it using the jumper. Major fire danger if there's an accident.
If it'll start and idle with the jumper in, it's either the COR or ECM. Both under passenger side kick panel. Try the COR first, it's a lot cheaper
Have you checked the efi fuse and relay? The IGN fuse? The AM2 side of the key switch?
I apologize if you've checked all these goodies already, I'm just trying to think of any possibility I can.
Good luck!
Pat☺
Have you tried shorting the Fp to B+ connectors in the little test jack on the side of the engine compartment fuse block? If you jumper them, and you can hear the fuel pump running, will it start?
CAUTION: DO NOT drive it using the jumper. Major fire danger if there's an accident.
If it'll start and idle with the jumper in, it's either the COR or ECM. Both under passenger side kick panel. Try the COR first, it's a lot cheaper
Have you checked the efi fuse and relay? The IGN fuse? The AM2 side of the key switch?
I apologize if you've checked all these goodies already, I'm just trying to think of any possibility I can.
Good luck!
Pat☺
thanks for the response. What is the COR?
Fuel pump is running, i have fuel pressure to the motor. All fuses and relays are good.
Last edited by chuck/rachel; 10-30-2021 at 06:24 PM.
10-30-2021, 06:37 PM
#4
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3.4 swapped, should be OBD2 at this point, I don’t think you have the old diagnostic port anymore, but I could be wrong..
Last edited by Discombobulated; 10-30-2021 at 06:39 PM.
10-30-2021, 06:41 PM
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10-31-2021, 09:30 PM
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COR=Circuit Opening Relay. It's a safety feature Toyota engineers came up with. It shuts the fuel pump down as soon as the engine stops, to prevent it from pumping fuel out during an accident. Prevents a major fire hazard.
The first gens, the COR is held energized by a switch in the MAF, that's closed as long as there's air flow through it. IE: The engine is running. If the engine stops, the COR de-energizes, and shuts off the fuel pump. The COR is located just above the ECU, under the passenger side kick panel. Bolted to the body of the truck with a single bolt. Easy to find, easy to remove, easy to install. Even in the later generations, where the ECU controls the COR, it functions essentially the same. Engine stops, fuel pump is shut down.
Does that help at all?
Pat☺
The first gens, the COR is held energized by a switch in the MAF, that's closed as long as there's air flow through it. IE: The engine is running. If the engine stops, the COR de-energizes, and shuts off the fuel pump. The COR is located just above the ECU, under the passenger side kick panel. Bolted to the body of the truck with a single bolt. Easy to find, easy to remove, easy to install. Even in the later generations, where the ECU controls the COR, it functions essentially the same. Engine stops, fuel pump is shut down.
Does that help at all?
Pat☺
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