1996 FZJ80 - CRANKS STRONG, BUT NO START HELP

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TNFZJ

TNFZJ

Low Speed. High Drag.
Joined
Oct 16, 2019
Threads
37
Messages
237
Location
Chattanooga,TN
I was on a recent roadtrip and had driven 6 straight hours. I turned the truck off to sign in at the hotel. I came out less than 10 minutes later… cranked strong, but no start.
Another 20 minutes went by and the truck started.
The next day I finished the last 6 hours of the trip. I left the truck running while pumping gas and stopping for food.
When I arrived home, I turned the truck off and then waited a few minutes to start the truck again. Would crank strong, but not start.
- I determined that the fuel pump is not turning on when the key is turned.
- Fuel pump does turn on with direct 12v power
- Using the jump wire in the diagnostic port does not turn on the fuel pump
- The fuel pump and assembly was replaced last year.
- The fuel pump relay in the fender was swapped with a known good relay
- Both the EF1 15a and ign 7.5a fuses are good
- The CEL does light up
- The battery light does light up
 
Last edited:
Any chance this is an ECT related issue where the ECU thinks it is starting a cold engine when it is actually hot? If you have an OBD2 reader you could check that the temperature being displayed is as expected. I'm guessing you would have noticed high fuel consumption if the ECT was the culprit but would ruling out anyway.
 
TNFZJ said:
I was on a recent roadtrip and had driven 6 straight hours. I turned the truck off to sign in at the hotel. I came out less than 10 minutes later… cranked strong, but no start.
Another 20 minutes went by and the truck started.
The next day I finished the last 6 hours of the trip. I left the truck running while pumping gas and stopping for food.
When I arrived home, I turned the truck off and then waited a few minutes to start the truck again. Would crank strong, but not start.
- I determined that the fuel pump is not turning on when the key is turned.
- Fuel pump does turn on with direct 12v power
- Using the jump wire in the diagnostic port does not turn on the fuel pump
- The fuel pump and assembly was replaced last year.
- The fuel pump relay in the fender was swapped with a known good relay
- Both the EF1 15a and ign 7.5a fuses are good
- The CEL does light up
- The battery light does light up
Click to expand...
There is also the circuit opening relay (COR) in the left kick panel. That relay feeds the FP relay. Both the COR and FPR are controlled by the ECU.
On an OBD2 80, the COR is the same part number as the EFI MAIN relay. Always a good idea to have a few spares.
 
broken timing chain ?

Unlikely yes, but it has happend .

Edit, easy to check for, open oil filler and have someone crank it over. Easy thing to rule out.
 
mrsleeve said:
broken timing chain ?

Unlikely yes, but it has happend .

Edit, easy to check for, open oil filler and have someone crank it over. Easy thing to rule out.
Click to expand...
If the timing chain is broken it won't start back up after waiting 20 min...
 
mrsleeve said:
broken timing chain ?

Unlikely yes, but it has happend .

Edit, easy to check for, open oil filler and have someone crank it over. Easy thing to rule out.
Click to expand...
@TheBussman @mrsleeve

Thanks, gents. It’s still something. I’ll check out though. appreciate it.
 
So has the truck restarted or is it dead in the drive way, thats why I mentioned the chain, if it still cranks strong and still dead even after cooling off.

Check your crank position sensor and wiring, might have sometihng heat realted going there as well with resistance or some such thing.
 
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