[Stvsmth8]

Im running into this problem even now in 2020. anyway those pictures still exist?

 

[saudade]

Sorry 'bout that. They were all in Photobucket. All gone now but I'll report what I have.

I circled the location on the splices. For some reason, 2 leads come from the firewall, get sliced into one, then later splices back into 2 that feed the injectors. Not even soldered, just crimped. one leg corroded and was intermittent. A quick snip, strip, and crimp (with solder) fixed it.

Good luck!

 

[saudade]

Here's a pick of the actual splices before repair. You should clean them all up while you have the harness apart.

Good Luck Again!!

 

[Stvsmth8]

HOLY CRAP! Thank you so much, I thought this was totally going to be a shot in the dark adding this comment. I’ll be sure to update once the car is out of the shop tomorrow but here is where we’re at now

I have a 1986.5 Nissan D21 hardbody 4x4 5 speed.
I Bought it this way, the truck ran absolutely fantastic other than a shitty idle, but if you went over 2800 rpm it would buck in limp mode. Since then I have bought a brand new throttle body with oem replacement fuel pressure regulator, injectors, wiring, connections, maf sensor, tps sensor, everything on it. I have also replaced the fuel filter and fuel pump. And cleaned the egr valve. It’s all getting put back together in the morning for the first startup since. So I suspect with the codes being cleared in the ecu already. If this truck doesn’t run right after everything I suspect the problem HAS to be the wiring harness fault or the ecu has gone bad. Thanks again

 

[saudade]

Sadly, I had to get rid of mine a while back. We had it since new. There are a few other "quirky" things about it.

So there are both intake and exhaust spark plugs. Each run off separate coils. Both sets of plugs fire at low rpms to help promote better combustion. One stops firing (exhaust I think) around 2500 rpms. One time I had an issue with it cutting out around that rpm. Turned out one coil was bad. I swapped the coils so it would run until I got a replacement.

I had the same issue later on, but this time was not the coil. I deduced it was a fuel issue. Turns out the 2 injectors in the TB work in a similar way. Both injectors fire at low rpms, one shuts off around 2500 rpms. This was the issue in this post.

Hopefully, yours will run great once you get it back.

 

[Stvsmth8]

I’ve cut apart the entire wiring harness and those splices you have pictured are nowhere to be found. On mine it’s 4 wires all the way from firewall to end I’ll attach a picture in the morning. After everything I’ve replaced it either has to be just a bad ground. Or that the injector control module inside of the distributor has gone bad. I’ve replaced the one that’s outside.

 

[Dycen11d]

Thanks for the input Burvis.


Let me try to clear up what is going on.

When driving, and only when driving. Each time you change gears and the RPM's drop to below 2500, as you try to come back up the truck will "bog down or lug" Not so much as to stop you, just enough to make the engine vibrate and shake.

I picked this thread because after an exhaustive search of this site this is the thread that most closely resembled my particular problem.

I understand that this was a TBI engine and mine us multi-port and a few years newer.


The fact that the problem sound so similar gives me hope.



It is almost impossible to tell any difference in the engine while it is in the shop and just sitting in nuetral even though I rev it up to the 2500 mark. It only seems to happen if the truck is under a load. I live in a very mountainous area so the loads are worse going uphill, which we seem to do alot LOL.

MY fuel economy has fallen off and of course the performance stinks. This problem is driving me nuts!! :wtf:



PLEASE HELP!!:waving:


I know you guys have the answer I need.

crystal

I have this same problem. Only way around it that I’ve done was disconnected my battery and reconnect it and it would last about a week and then start doing the bucking phase again