Help, Poorly Running 80

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F

fj40fax

Joined
Oct 19, 2003
Threads
11
Messages
122
Website
www.dccrusr.com
'95 FZJ80 all stock.

I tried a search for this, but it is difficult to describe in a searchable fashion.

The 80 has been running poorly for about a week. It would stumble only on initial acceleration, then catch and run just fine until coming to a stop again. Even under heavy acceleration from moving it will downshift fine with plenty of power.

This afternoon when almost home the stumble got much worse and lost nearly all power. Had to shift into 4lo just to get up the hill to the driveway. When I restarted it it idled really rough, and still has no power (just backed it out of the driveway and back in). While in park it seems to run better at higher RPMs, but it feels like it is down a cylinder or two at idle RPMs.

I have ordered new plugs, wires, rotor, and cap as a start. Anyother suggestions would be greatly appreciated.

Thanks,
Fax
 
Fuel filter and PCV valv and grommet might be other things to swap out. Your attacking the right problems, fuel and spark.

Have you checked the timing?
 
fj40fax said:
It would stumble only on initial acceleration, then catch and run just fine until coming to a stop again.
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Check the intake hose for cracks and any other type of air leak.

-B-
 
Beowulf said:
Check the intake hose for cracks and any other type of air leak.

-B-
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Also the engine harness where it passes by the EGR pipe. That would be more random than a cracked hose.
 
cruiserdan said:
Also the engine harness where it passes by the EGR pipe. That would be more random than a cracked hose.
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Aren't you supposed to be doing inventory? It's not even 10pm and you're home playing on the computer? ? ? ?

-B-
 
Funny you should mention the intake tube. It has a giant crack in it. I taped it up a week ago, and ordered the new hose from C-dan yesterday along with the plugs and wires. The tape still looks good, maybe I'll retape it and see if it runs any better while I'm waiting for the tube to come in.

Dan, do you mean the electrical harness by the EGR pipe? I can look there too when I get home.

Thanks all.

Fax
 
I went out and taped up the intake hose again. Still could not see any gaps or holes, but tried again. Still runs very poorly, with a distinct smell of gas in the exhaust. I'm really thinking spark now, and all of the spark stuff is on the way. I will replace all of that stuff and post up again if it doesn't fix the problem.

Thanks,
Fax
 
OK replaced the intake hose, plugs, wires, cap and rotor. Still the same. It ran good for about half a block, then went back to the low power, unable to get above about 1700rpm while in gear. Again had to put it in lo to get up the 50yard hill.

What's next?

Thanks,
Fax
 
no codes correct? your check engine light does work? it lights when you first turn the key to on?

you are not excessively loosing oil right? and sometimes it runs good? if it sometimes runs good then it cannot be internal condition of the engine,

If no codes I am thinking possibly fuel delivery problems, the ECU seams to be pretty good at watching the primary ignition system and for misfires, and you have replaced most of the secondary ignition components.

when I had fuel pump relay problems the computer was none the wiser, just ran like crap sometimes.
 
RavenTai said:
when I had fuel pump relay problems the computer was none the wiser, just ran like crap sometimes.
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That's were I'd head next, especially if the truck runs good with the skinny pedal well pressed. That's when the fuel pump relay switches to the high side.

I've got a kitchen draw repair out there somewhere's
 
Check engine light does work. Was throwing a P0420 I believe for cat not up to snuff before this started happening. Exhaust leak (gasket) is also being taken care of that is between cat and O2 sensor #2. No other codes that I know of, but I haven't let it run long enough and don't have a code reader at home.

Fuel filter, relay, and PCV on their way ASAP. It has not had good TLC for a little while, so this is all good while there is $ in the account. Any other suggestions for good PM? Brakes are new as of last year (5K miles).

Thanks,
Fax
 
I would get a code reader, Fuel pump relay is expensive PM but it is the next logical step, cleaning it per Ricks instructions might have been a better 9cheaper) step but straight replacement is not unwarranted
 
Check the engine wiring harness where it passes by the EGR tub at the back of the cylinder head.
 
Just went out and looked. The plastic clip is broken, and there is a small spot that is melted where it contacted the tube. Can't tell if it has melted through the heat shield or not. How the hell to get a better look/repair that. I can barely contort enough to see the spot, let alone get my fat ass in there to fix it. Do I unbolt it from the firewall? Suggestions welcome. Thanks for the help.

Fax
 
Get a couple of 2x12 lumber, a bright light, and lay up in there with it. The broken plastic clip is fairly common but you should not have melted plastic loom or wires.

Once you isolate and repair the problem, get some good heat tape from a speed shop or Jegs or Summit Racing and insulate that area well.

-B-
 
Ok some new symptoms. I went out this morning to see if I could run it long enough to throw the CEL. When I started it up the CEL light came on like normal and went out, good. But I shifted it out of 4lo from getting it up the hill and now the ABS and CDL light won't go off. Still could not get it to throw a CEL, and it does seem to run well above 1200rpm.

Where is the fuel pump relay? No FSM (soon to be rectified) and couldn't find it on any of the fuse covers.

Took another look at the wiring harness by the EGR and it does not seem to have gone through the heat shielding, I will delve further into the wiring harness after checking out the fuel pump relay. If I have to replace the entire engine wiring harness I might just do the HG PM at the same time since half of the intake will already be off.

Thanks,

Fax
 
Nevermind about the CDL and ABS lights. Backed out of the driveway and back in and they cleared.

If in gear, I cannot get it to run well, like it is stuck under 1000rpm. If there is no load, in P or N, I can rev it above 1200rpm and it seems to run just fine (sounds and feels normal).

Fax
 
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