280z random stall/rough idle/lots of black smoke problem solved

[elkarin1984]

Hey guys, new guy here and new to the Z forums and community.  First of all i don't want to anger anyone, i just want to share my experience and how a few issues got solved, so i hope Im not writing in the wrong section or reposting.

 

To start of i bought a 78 280z last year, the guy had bought it from another person who had damaged the engine, so the newer (prior to me) owner thankfully installed a F54/P79 in the car from an 83zx.  The day i went to check it out the car did not want to start at all, sounded like a car running on carburator and lots of black smoke.  So went home sad and the a couple of days after he called back saying he got it to star, because he used to drive it daily before he said it was strange it did not start that other day (i just taught the Z did not want to go home with me).  So we checked it out and, ran and sounded good so i took it for $2800 (he wanted $3200 but due to the start issue he dropped the price) since he said i might need to spend some cash to figure it out.  

 

Well it ran pretty good for a while then suddenly it did it again, randomly and stalling while driving on the freeway.  I could not figure it out and it was really frustrating, because it would stall and start right up after a couple of minutes.  so to make things short it got to a point where it was more often than i would like for it to happen, since it is my daily driver to work, it happened to be that the harness to the ECU was not properly connecting.  It clicked good, seemed to make good contact to the ECU but any hard bump, or vibration would cause it to stall and have problems re-starting.  I started by pressing the harness to the ECU and noticed it would start right up, but would die a while after letting go (it happened once while driving on the street so i had to put it on second, press the harness with my left hand, start it and drive with the right hand, so you can imagine how i was positioned jejejeje)

I had to take the ECU out of the car and the tab that holds the harness to the ECU was the problems, due to age and use it was not putting enough pressure to keep the harness from loosing contact.  I drilled a small hole across the tab into the ECU while the ECU was open to ensure no electrical components where damaged.  Screwed in a small screw and that is all it too to fix a lot of headaches, and almost selling the Z as well due to that...  So there might be a lot of guys and girls out there having some "gremlins" that cannot seemed to be solved, try this out and you might save yourself a lot trouble/cash/green hair trying to figure out something that could be RIGHT UNDER YOUR NOSE.  (of course i spent the cash on other things trying to figure it, but ended up with new BOSCH type connections on the car now)

 

I dont have any pictures but it really is not that hard, it might sound scary but there is plenty of space in there to do the rig that i had to do....  Come on, there are other things harder to do on this cars, chop off, or modify, so don't be scared!!!!

[Pharaohabq]

Thanks for the advice..  I doubt many of us on here are scared of modifying our cars or the connections and any of the wiring. Your issue is certainly uncommon but the trouble shooting procedures outlined in the FSM should have caught that issue.  It's great you worked up a solution to repair it.  I probably would have put a piece of wire around it to hold it in there. That or something similar to what you did.

 

It does go to show, though that a community of like minded individuals can solve most issues.  We appreciate your sharing your experience. I'm sure we will remember to check the ECU when we are having strange issues..

 

Thanks...

[osirus9]

That's pretty awesome. The best solutions are ones where you use your brain and a bit of free stuff lying around!