1994 FZJ80 Fuel Delivery issue (1 Viewer)

Joined
Jan 27, 2015
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I purchased a 1994 FZJ80 on covid clearance back in May. It's ugly, ran rough as hell, and the brakes were shot when I got it. I purchased it to use as my wheeling truck and retire my 93 triple locker to lighter duty (stop doing things highly likely to cause sheet metal damage).

I replaced the brakes and was able to get it running like a creampuff by replacing the knock sensors and temp sensor (all physically broken off) as well as replacing injector #6. Ran great for about 2 weeks, then I let it sit for a couple of weeks due to work and the battery died. I tried to jump it off, but it was shot so I replaced the battery and then it just simply wouldn't start. I checked and it is getting spark. I can spray starter fluid in the intake and it will fire right up and run until the starter fluid is gone then dies.

I checked the fuel pump relay and it is good. Even swapped it with the one in my 93 to confirm what the meter said. I checked the fuel pump with the meter and ironically it was dead so I replaced it and it still wouldnt start. I replaced the pickup filter and the inline filter when I replaced the pump. I drained the tank and there was some trash in it but not horrible. When I disconnected the fuel line to at the tank to replace the pump, the gas was nasty that came back out. I let it drain out. When I disconnected the lines at the filter and drained the gas there, it was clean, however the filter was pretty gross inside. It still will not start now that its all put back together.

Has anyone had issues with the fuel pressure regulator causing these issues? Is there somewhere else in the fuel delivery system i should be looking? I am pretty familar with these things, have the FSM, and i am completely stumped and am welcome to any advice at this point.
 

ppc

M Go Blue
Joined
Aug 18, 2003
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Nashville, TN
First thing I would do is measure/monitor the fuel pump voltage at the diagnostic connector while it is running on the starting fluid.
Next measure the voltage at the tank checking all connectors for corrosion.
Measure fuel pressure at the fuel rail with a gauge or loosen the fuel pressure regulator to see if any fuel leaks out.
After those results we can best provide additional suggestions.
 
Joined
Nov 9, 2012
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Olathe, KS, USA
What I have seen reading all these posts with it running on starting fluid, it tends to be the IAC valve.

Also, since you've messed with the battery, do you have a CEL with key in the RUN position? If not, check fusible links first.
 
Joined
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Messages
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North Carolina
What I have seen reading all these posts with it running on starting fluid, it tends to be the IAC valve.

Also, since you've messed with the battery, do you have a CEL with key in the RUN position? If not, check fusible links first.

No CEL unfortunately. I would love to have a CEL at this point to at least have a direction. I have checked all of the fusible links and chased all the grounds to make sure there aren't any issues. I am trying to see if I can rig up a way to check fuel pressure with what I have, but probably need to purchase the M12 valve...…..I'm worried that I may be chasing 2 issues at this point. One fuel and one electrical.
 
Joined
Nov 9, 2012
Messages
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Location
Olathe, KS, USA
No CEL unfortunately. I would love to have a CEL at this point to at least have a direction. I have checked all of the fusible links and chased all the grounds to make sure there aren't any issues. I am trying to see if I can rig up a way to check fuel pressure with what I have, but probably need to purchase the M12 valve...…..I'm worried that I may be chasing 2 issues at this point. One fuel and one electrical.
If you do not have a CEL with key on, then the ECU is not in a ready state. There is a sensor not allowing it to operate or you have a blown fusible link.

Go through the troubleshooting list.
 
Joined
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North Carolina
If you do not have a CEL with key on, then the ECU is not in a ready state. There is a sensor not allowing it to operate or you have a blown fusible link.

Go through the troubleshooting list.

Clarification, the CEL comes on when you put the ignition to the on position, there just isn't an error code from the CEL. Its pouring rain here today, so there will be no forward progress today.
 
Joined
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Atlanta
Look in your fuel tank. Mine was nasty and caused me all kinds of headaches. Also note that a brand new filter can clog up pretty quickly.
 

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