# Help needed: 1986.5 hardbody, z24, hot restart missfire



## BillTomerlin (Nov 7, 2011)

Hello guys. I used to be a member on here years ago as "Pathfinder_1988" but I can't remember any of my old stuff. I really need your help. 

I have a 1986.5 Hardbody with the throttlebody fuel injection z24 engine and a manual transmission. It is the 4wd model.
What I have is somewhat unusual. When you start it cold, it runs fine. No issues other than a very occasional miss. It runs fine, and has the expected power. When you drive it and warm it up (3-5 miles) then bring it back, it again runs fine. The problem arrises when you turn it off, and let it "hot soak" for 25-45 minutes. no less, no more. It will start, sometimes stalling, then idles rough. it has no power, and cant even pull itself up a slight incline. So far we have replaced the following: both coils, all spark plugs, cap/rotor, throttle position sensor. There are no codes stored. If you let it run for about 10 minutes, it will smooth out and begin running just fine. I am leaning towards the coil module, but since there are 2, one intake and one exhaust, I am not sure where to go. They are expensive, and I need to get this truck reliable again for my friend. I don't know if the exhaust module could affect the engine running or not, so I am thinking intake module. I have tried disconnecting the modules while the engine was running normal, and poorly. When I disconnected the intake one, engine would begin missing and hesitating, when disconnecting the exhaust one, there seemed to be no change in the engine operation in the garage. I ignored this, since it is identical when engine is running poorly, or normally, but I wanted to mention that here. PLEASE respond and help me out. I can't find a wiring diagram for this model truck anywhere, so I am at a loss for doing any type of pinout testing.
:newbie:


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## smj999smj (Jan 1, 2006)

Have you tried swapping the intake coil wire to the exhaust coil (and vice versa) and seeing what happens? I used to use this method to identify if a coil/transitor assy. is failing.


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## BillTomerlin (Nov 7, 2011)

Yes, I have already tried that. Sorry that I forgot to mention it.


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## zanegrey (Dec 5, 2005)

check temperture send unit


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## yellowrosefarm (Dec 11, 2011)

I had the same problem but mine would not start at all on the hot soak. The main relay is common to both coils and replacing it seems to have solved the problem. It's only 18 bucks so it's a cheap try.


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