Hey all, My white 1989 z32 2+2 TT auto had recently started dropping cyl#5 at random so I changed out all the plugs for new coppers and the same problem. I then changed out all the injector connectors and fixed the dodgy coilpack connector on #5. It was still dropping at random so I checked the resistance on all the injectors and coilpacks, all ok. Figured it's probably the PTU so I installed a s2 with pigtails and it ran on all 6 but when I jiggled the loom from the PTU it dropped 5 again. Assumed it was the pigtails so I cut them off one wire at a time and soldered and heatshrinked them up. Now it wouldn't start at all! At this point I assumed the problem must be further up the wiring harness so i cut back the loom from the PTU to find some absolutely horrendous solder joints and exposed/broken/corroded wires... great. Not giving up here I took back the loom to where the wires still looked factory fresh and cut and attached new wires. Still not starting! Battery is fully charged. No massive air leaks. This car really is driving me bonkers, it's exams next week and I just can't get myself into study mode unless I know the car is alright. So basically, where do I go from here? [TIS]
Forgot to mention, tried a known working s2 PTU no go. Check the continuity of the wires from the PTU harness back to the ECU? Thanks for the fast reply : )
the PTU to the coil pack. something might have happened. its easy to check, ptu pin 1 to coil pack tigger 1 ptu pin 2 to coil pack tigger 2 right thru to 6. you may have got some wires mixed up. hard to expain, but you might work it out.
Are you sure you've got the black wires going to the right connector? There should be a single black wire from one part of the harness going to the connector on the other part of the harness.
yes make sure the wire that loops from one side to the other goes to earth, check it with a continuity tester, there is a black wire that feeds one of the coil packs and it is easy to swap these over. So in short as the others have said make sure the wire that loops does inded go to earth and not one of the coilpacks.
Yup, many many thanks to Chris for coming round and pointing out my brainfart and also many thanks to the posters above, however it turns out I was just back to front *face palm* Put new injector connector and coilpack connector on offending cylinder with random miss and no improvement. Oh the joys of wiring harnesses.
Thread dig just in case it comes up in a search for someone and there's no solution listed... Cut the wiring harness back from the offending coil pack connector to find brittle and split wires, cut and soldered new wires and rerouted coilpack and injector connectors through the main valley. Replaced spark plug that had been fouled by the intermittent missfire and voile back to her old self : )
