So I just bought a '89 300zx TT. Its got rather rough idle/miss and is running considerably Rich.
I initially thought O2 Sensor would be gone. I ran the Self Test on the ECU. I got Code 21 which is Ignition Signal circuit. I can understanding this causing it to mis/run rich.
Problem is Im not too familiar with the ignition circuit on one of these. I can tell by looking at it it as Individual Coil Packs, but thats about all I can see. A quick google showed that it could be a PTU! Unit or Crank Angle Sensor causing the code as well. Where would I Locate the PTU and how can I check its operation before ordering a new part! And is there anything else in the Ignition system that can cause that code!
Cheers
doug207,
Apr 9, 3:20pm
There are a few Z32 specific forums out there, may be worth a try.
Good luck, bloody nice cars.
phillip.weston,
Apr 9, 3:28pm
sounds like a dud coil pack. I would try unplugging them one by one until it doesn't make a difference when you unplug one.
unbeatabull,
Apr 9, 3:42pm
I initially thought coil pack as well, but have read that the PTU unit can cause a single coil to not fire as well, I guess the best test will be to find one that makes no difference then swap to another cylinder and see if its still no go. Too bloody cold to do it now though haha
unbeatabull,
Apr 10, 2:36pm
So I had a bit of a tinker with it this Arvo.
I found the Right Rear Cylinder (#5 or 6) to be the one with the miss. I swapped coil and Plug over to another cylinder and they work fine. So I thought it must be something to do with the plug/loom.
I checked the plug. I presumed one of them was an earth which was fine, no resistance in it, one would be a constant voltage! Which I found and was ~15.8V when running, and the last one would be a switching/signal circuit to tell the coil to fire - This I couldn't get any reading out of and was open circuit.
What would the next step be in finding the problem!
71ace,
Apr 10, 5:32pm
just a thought, did you check the injector plug is connecting properly, have had several arrive with corroded injector plugs dropping a cylinder off & on, worth a look
unbeatabull,
Oct 18, 1:43am
Will check the injector tomorrow once I find it . Never realised how cramp that V6 is in the engine bay in one of these things haha
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