Ok story so far for those that have missed my last few threads.. I do a routing plenum pull (install SS braided hose, paint etc... - have had it off plenty of times - takes like 35minutes with a beer now all up). Go and put all back together.. she cranks over but no spark.. do ecu diags - code 21 - primary ignition. Check all harness connections etc (btw I have S2 PTU).. to no avail (harness wasn't even disturbed during plenum pull but thought what the hey you never know). Install original S1 PTU - beast fires up... figure Failed S2 PTU for some reason (advise has been it is almost unheard of for them to fail). Go for a nice drive with S1 PTU still installed (after a few round to block runs to test her out). After 45minutes of drive car shits the tin... just dies... roll into a carpark (thank god) and do some diags on her.. code 21 again.. preceivably dead PTU (again).. Pay $90 to have baby towed home... Question: is there anything that could be "burning" the PTU's out.. has anyone had straight out failure of S2 PTU. Any clues on where to start looking for a clue... I have done a continuity test of the S2 Sub harness and every pin tests perfectly... Very Confusing.. and most annoying... someone please help...
Hey there, i'm very new here but ive had a fair bit of experience with these damned z32 igniters and have found that alot of the time it is an individual pin or in some cases a few or all pins on one of the 2 connectors to the igniter backing out and no longer making contact to the igniter, replacing the connectors has solved alot of these missfire/no start problems for me, but of course every car is different....
Did the PTU diags in the FSM reveal the PTU was dead Have you tried the PTU diag as per FSM? IF it is electrical maybe something is shorting... did you remember to connect the 2 earth points at the rear PLenum? Donovan
Good point donoryan re the two earthing screws on top /rear of plenum. Thats one to check. I had an unusual one recently where a zed motor wouldn't turn off... only when the ign relay was pulled would it stop. Turned out was the ECU not killing the ign signal. New ECU fixed it... I *wonder* if your ECU is doing the reverse and not intermittently not providing an ign signal. ALSO have you removed the ECU lately... the ECU wiring loom can do strange things if not completely inserted onto the ECU... I'm also starting to think that it might be a broken wire somewhere along the circuit. You say that the connectors are fine for continuity but perhaps there is a break along the wire away from the connectors... When you swap PTU's the physical action of moving the PTU loom to plug the 2nd PTU in might be enough to reinstate the connection then later with some vibration etc the wire disconnects... I'd try a continuity check on the orange wire between the ign relay and the PTU (orange wire) while you shake and twist the PTU loom...
I'm sure I did connect all the earth points.. but if I missed them.. would this kill the PTU's or just cause the ECU to not provide a ignition signal properly..
I'll give this a try also... Thank you so much so far for all your help.. It never ceases to amaze me how willing people on here are to give a hand.. benefits of being part of such a group.. I haven't removed my ECU at all recently (not for at least 4 months anyway and it is a daily driver).
Make sure you iron out the possibility of the S1 unit has failed because of temperature. Did the engine fire up again once it had completely cooled down with the S1 unit? If it did I would bet that there is an issue with the connection between the orginal harness connectors and the S2 sub harness, as some other members have experienced this. If this turns out to be the case, chop off the new S2 plugs and graft them into the orginal wiring harness. That's what I did, no problems and looks much neater.
