Yep, i pulled the CAS, and all plugs are new. The old ones were black and sooty, the ons in there now are still fresh metal. I knew the risk of fouling expensive iridiums so just put some cheap ones in for the moment. all injectors are clicking, tested with the stethoscope and while the plugs were out (fuel squirting and vapourization all present). spark seemed a little weak when tested out of the engine. Does the Z32 have variable spark intensity?
I'll Check that one, IB. ECU was replaced, and re-connected, and tightened with the 10mm bolt. I am apprehensive about over-tightening the bolt, as it only has plastic threads on the ECU. I am fairly sure it is seated properly though. :zlove:
Re the ECU loom bolt Good thought as if you overtighten the bolt the ends can bow out. So worth checking that the ends are firmly seated. Re variable spark = no. Just checking. So the donor ECU has provided the ignition signal to the ign circuit yes? Ifso and you still have a code 21 then you still have a break somewhere in the wiring... Have you tried just clearing the fault code? Does it come back up instantly?
I find a light spray of WD40 helps the connector fully seat as the ends can bow out as you do the bolt up.
The spare ECU still shows up the code 21, but this time allows spark. Ill swap in the Old ECU, because i haven't tested that since i have hard wired in the new PTU. I have a feeling the old ptu harness plugs weren't seating correctly. As for clearing the fault code, as soon as i clear it, it re-appears. I have tested the wiring for continuity, but i will do so again to re-confirm. I also remember the guy at repco said that the spark plugs i got were colder than the ones i had, as it will resist fouling. might that be the cause of the weak looking spark?
I have had this before and got suckered in, The spark has to look WHITE when it fires. I had "a spark" in a car once when checking it. It looked a bit pathetic but I was sure it was OK. after pulling my hair out for a day or two. I realised the PTU was still not right. Check for a nice white intense spark, not a pathetic blueish one. I bet your PTU is still not right.
Today i swapped out the spare ECU and put the original back in. Still getting spark, but not holding idle. Thinking that the TPS might be out (going to check out the tech article for that) and look into the IACV adjustment. It seems that now i have spark, but the engine wont get a hold of the timing enough to maintain idle. Ignition revs engine up to ~2000RPM, but then dies. Feathering the throttle does not do anything for the engine. I have confirmed that the ECU harness is securely attached to the ECU.
The Z lives! It's ALIVE! Note for others chasing a similar problem, be sure to check the IACV adjustment. After the rough idle before the previous PTU died, idle was changed. With the new PTU, idle air was way too much, leading to the engine running, then stalling. Turn iacv screw fully clockwise until fully closed, then turn back ~2.5 turns. This will be a good basis for fine tuning (enough to get a 900 RPM idle) After a TPS adjustment, it should all be good to go for a nice long road test. Here is the old girl happily chugging away after all those countless hours of chasing gremlins caused by bad PTU's, non-working wiring harnesses, and badly adjusted IACV's http://www.youtube.com/watch?v=Q1QYG59yUHY Enjoy.
