Need help before I have to sell this thing...

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Jeff Elliott

Jeff Elliott

Joined
Jun 9, 2017
Threads
111
Messages
943
Location
Denver, NC
Hey NC guys -

If any of you follow the 80 series section you may have noticed my thread trying to deal with a #4 misfire on a new to me, low mile (87K) FZJ80. Well, I've done just about everything I know to do to this rig and am still plagued by the misfire. My trials and tribulations can be seen here:

Final thoughts before I sell it? - Runs rough, CEL and P0304

I was wondering if any of my local peeps might have advice on what to do here before I post this thing up for sale which will break my heart and my wallet. Would appreciate any and all suggestions!

Best,
Jeff
 
When you 'repaired' those wires did you replace the fxxxed portions or just add new insulation?

Make sure your injector wires aren't swapped.

FYI...I'm just mentioning random s*** that you've likely already marked off but sometimes it's the obvious stuff that is the hardest to troubleshoot. Like when I'm cursing where the remote is and its in my hand. SMH.
 
Thanks @S4Cruiser - Yes, I pieced in new wiring for 4 different wires and verified continuity across all. That said, my most recent attempt to solve this involved completely bypassing the factory wiring (including my repairs to ensure that they weren't faulty). I've got a pulse wire run directly from the ECU to the #4 injector and the +12V for the #4 injector has been fed from another, known working, injector. This isolates the normal issues with the loom inside the glove box, passing through the firewall and passing the EGR tube.
 
Are you thinking about selling it because you can't figure out the issue, or because you're flipping the truck?
 
Because I can't figure it out @GLTHFJ60 - I wanted to keep this thing forever and that's why I paid a lot for an extremely low mile rig. The saga has been pretty bad as I:

  • Had the rig inspected by an independent shop in CA before sending the money for the truck and got a clean bill of health
  • Had it picked up by a shipper who had no trouble getting it on the semi but had to take it off to load another truck and then it wouldn't start
  • Shipper abandoned the rig in Long Beach and I had to get someone with a winch truck to come get it
  • Rig got here and I immediately determined the no start issue - no batter bracket allowed battery to move forward and destroyed the fusable links
  • Replaced those and she fired up but ran like crap and thus the P0304. Have been chasing that since then
Thanks to all
 
Try h&h and see if they can figure it out. What is the compression on #4.
 
Roxx said:
Try h&h and see if they can figure it out. What is the compression on #4.
Click to expand...

Thought about that. If the new ECU doesn't pan out I might have it towed down there (although my hood is off to allow access to work on everything!).

Compression numbers were 170 - 175 across all cylinders including #4 so all good there. Have also done the block tester which indicated no HG issue.

Thanks!
 
Oh wow, that's a bummer.

I have an ecu here at the house you can try to rule that out.

I'm confused by your test in post #3. You're saying you created a harness from the ecu to the injector on cylinder #4 (to rule out harness problems) and the issue persisted?

Verifying continuity is insufficient. You need to make sure there is sufficiently low resistance as well. Internal corrosion in the harness, or a nearly complete break of the wire, can cause a problem that you wouldn't necessarily detect with a continuity test.
 
@GLTHFJ60 - Thanks!

Here's what I did:

  • I used a brand new injector harness
  • I connected said brand new injector harness black with red wire (12V) to the adjacent #3 injector black with red which is known to be working
  • I connected the other side of the new harness (the yellow wire for #4) which should be the pulse wire to a brand new length of wire from my spool of 16g wire in the shop to the #4 injector pulse pin on the ECU (see pic)
  • I also verified continuity between the saddle connector (blue connector in the pic) to the ECU pin on the front side of the harness connector
Thus, I've completely (I think) isolated all the variables from a harness standpoint. Happy to hear suggestions as I'm out of ideas other than the ECU.

And thanks for the ECU offer - I've got one on the way that will be here on Monday.

27732249498_4c674c7cf0_h.jpg
 
Yup, only code I'm getting. Have thrown others but they are from stuff I left disconnected (MAF, etc.). The only code it throws when driving is the P0304
 
I do have a ecu. What year again?
 
Roxx said:
I do have a ecu. What year again?
Click to expand...

It's a 97 but can use a 95-97 I think?

Either way, I have a new one coming on Monday so appreciate the offer but should be able to test that out when I get back on Tuesday
 
The original ad has this:

"<EDIT> The truck has a stumble when going from light throttle to full throttle quickly. I think it's just a clogged fuel filter because it started doing it after sitting for 3 months."

Got nothing else since all the smart folk jumped in, but this is curious...
 
little_joe said:
The original ad has this:

"<EDIT> The truck has a stumble when going from light throttle to full throttle quickly. I think it's just a clogged fuel filter because it started doing it after sitting for 3 months."

Got nothing else since all the smart folk jumped in, but this is curious...
Click to expand...
I agree. But I had it checked by an independent of my choosing... The PO didn't even know the place existed. I guess it's possible that the PO threw a few bills at the independent but I'd find that unlikely.

The independent checked the truck pretty well and gave a fairly detailed report - that's why I wired the money. The truck still has some great stuff on it so it's not a total loss but it sure would have been nice if it ran right from the start. Hopefully the ECU is the problem... FYI, the PO did change the ECU to try and cure the stumble.

Thanks!
 
Completely read your 80 section thread, quite the adventure - man you are persistent and methodical about it, which will eventually lead to resolving this.

The #4 injector just doesn't pulse/inject fuel? Since I am a complete idiot, I'd pull the injector but leave it wired, then have someone turn the key for a second. Probably wouldn't prove anything, but if it mysteriously worked outside of the engine... (thinking maybe it is grounding/shorting when installed?)
 
^^That's what I was thinking. Could be a bad injector.
 
I'm unsure if the 1FZ is batch fired, but I doubt it's sequential. Confirming that, you could swap the injector leads and see if the problem follows to a different injector or stays with #4 (verify electrical / ecu vs injector issue).
 
@mtweller , @GLTHFJ60 , @little_joe - If the new ECU doesn't work, I'll give that a try!
 
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