I'm just going to be silly and throw a bunch of crap in here - all completely over the top but all very possible if money were not an option: Buy a 98 spec gearbox Why? because hall effect sensor boss on bell housing to trigger from flywheel = ficken cool! Split fire coils Why? because they are blue & will look pretty, they aren't worth a tin of crap for performance but you will feel good knowing they are blue so at least look like you have spent money on them Wiring harness from Coz Why? because brand new even if not quite as good quality as OEM was but new all the same so will be much bettererer. Might even resolve a bad earth issue or accidentally swapped over wires to one of the coil packs (you know the one that has the black wire that looks like the earth wire and causes people to fick up the wiring and blow transistor packs every other day because it will still work but then fail after a period of time due to a poor earth through the coil rather than the chassis Christ this is a long sentence and I'm running out of fricken page!!!!) Link 300zx G4 plug in ECU Why? Because it comes in a pretty box and it's going to make the new gearbox worthwhile, you can literally plug these things in and be driving the car in five minutes , tuned in less than an hour - ficken cool A second hand series two PTU with harness Why? because when you test all this crap you don't want to blow a brand new one up do you LOL!!! Hard wire the new plugs to the harness - oh wait shit I'm stupid you already have a new harness and it comes with the series two plugs because that's what the smart man ordered. Still test with second hand PTU first, sell it when you are happy and fit the new one. Actually you could most likely ignore everything except what's in brackets & just try that - I'll get cocky and call a pre-emptive "you're welcome" - go on someone miss the humour in the post and have a go at me so the rest of us can laugh at you.
Nice AEM CDI unit sitting here waiting for you MITCH. drive it straight out of the ECU .......................
Mitch, that's prolly the most intelligent post I've read regarding PTU's in the past 6 months!! Seriously though, if you've blown three, it's unlikely to be a PTU fault. Were they all new or second hand? If second hand, has the wiring loom been spliced to adapt to the S2 plugs? Are there any shorts in the wiring loom? Are you running a stock ecu, alternator and battery? Are the coils stock? Have you changed the coilpack connectors? Is the engine earth intact? Is anything else going wrong with the car - oh - silly question .... it's a Zed!!!! How do they fail, ie does the car just stop running suddenly, drop onto less than 6 cylinders, etc. How long has each one lasted? Did you end up with an S2 unit 'cos your S1 failed too? Happy to try to offer some keyboard advice if you can give a bit more info. Cheers, Dangerous.
How about going back to a series 1 ptu. Maybe you put the short in when you rewired. S1 ptu's are cheap and plenty of them out there. I'm still running a S1 in the convertible (buy I've got a spare in the glove box) The S2 never made out of the shelf in the garage
VT 3.8L ecotec uses a "Direct Ignition Module" as opposed to a "PTU". Rather than using a 6 channel signal from ECU. It inputs directly from a CAM Sensor and Crank Sensor. And signals from ECU (or PCM) called: CAM, 18XCRANK, REF HI, REF LO, EST and pin D9 (maybe called BYPASS). If you can find individual power transistors that are compatible. Rather than replacing whole PTU you may only have to replace single transistors. Ie rather than whole unit. I don't know if there compatible. But AFAIK, the Z31 used single transistors rather than a whole unit. Dunno how you would go trying to fit a distributor from VG30DET single turbo. I think there's plenty around though. Regards. Z31 power transistor.>>>http://www.mygen.com/users/dbruce/myz31/FSM/z31 Ignition signal.jpg http://www.xenonzcar.com/z31/images/Sensors/powertransistor.jpg
Convert back to S1, see what happens. PS open one of those blown S2 PTUs and post a pic please PPS: a PTU cooler (get the blue one)
I aim to please, and this thread delivers First to go was new. Second to blow was used- under 1000 km lifespan. The last one lasted maybe 5 kms. Literally the drive to and from the nearest exhaust shop (the second to last failure burnt thru some really nice high flow metal cats). Wiring loom tests ok for continuity from point to point. I presume there is a short somewhere, but not sure where to look first. When a ptu blows, it seems ok at idle, drives fine, but turns to a Dropped cyl. Then it becomes a no start- with or without a code 21. Coil pack connectors are ok. Coils themselves are original- migh do the resistance test to see if they are ok- could a dead coil effect the earth to the ptu? So it's got me beat. The harness I soldered myself well before the new ptu went in, so it should be ok- perfect joints with heat shrink in all the right places. Even staggered the joins so it wasn't bulky when I unwrapped the loom for the relocation.
has anyone bee messing with the ECU, Ie nistune et-al? Id be having a look at the coil-on (dwell) time. I made this mistake one with my old FJ20. Left the dwell time on DUTY (50%) by mistake after fiddling with the ECU's head. I melted the imprint of a Phillips head screw into my index finger the PTU was so hot. E
How did the failure burn through the high flow cats? I'd be thoroughly checking PTU and coilpack wiring, and if nothing found, replacing all of the coilpacks, if you have access to another set. It sounds like the cause of the failure is intermittent, so resistance testing of them might not uncover a short. The PTU should be impervious to battery voltage problems, as it only switches what it's given - it doesn't have a battery voltage connection to it. The transistors inside the PTU that switch the coil current rely on the coil primary resistance to limit the current through them. If one coil or the wiring to the coil has a short that appears when it warms up, or with vibrations at higher revs, it could kill the transistor, which may in turn kill the earth connection for the PTU. It would be interesting to pull apart one of your failed PTU's and see what's died. Tas also made a comment about the dwell time. That's a valid one if your ecu timing's been played with. If the ecu turns the PTU on for too long unnecessarily, it can overheat the PTU or the coilpacks. If you've got a stock ECU, this won't be the case.
The wire it is - black wire - caught you out - get it! - then replace - careful you must be - a Zedi warrior must know if wire is dark side for if not PTU you will blow.
Unburned fuel apparently. If you're interested in rewiring. For the constant voltage rails. Ie Engine Ground to Secondary Coil, Ignition Relay to Primary Coil. I would consider using up to 6AWG. PTU to Primary Coil. Probably up to 10AWG max. Individually shielded. And ECU to PTU probably up to 14AWG. http://z32.wikispaces.com/file/view/ECCS_colored_m.gif Not that hard to remember. V = IR Have you simply bolted/screwed PTU to panel. If I was relocating PTU I would seriously consider using heavy insulation against conduction between the PTU case and any body panel. Or anything.
Have you tied pulling apart the p.t.u to see what exactly is going on and if it is a certain cylinder. I bought this great tool from Jaycar that is for doing electrical test on cars and one of the great functions is you can hold the tip against coil packs and it tells you the firing voltage this would be a great test for your car as it may well tell you if it is a particular cylinder then if you change coils around but still have the problem on that particular cylinder you could go further with wiring or e.c.u if the problem moves with the coil you would be thinking coil related. It,'s a test that takes seconds. There catalouge number is QM - 1494 Automotive Multi Function Circuit Tester and for $ 49.95 it's a bargain. You can also use it to put positive or negative power in to components directly to test them which is fantanstic. Cheers Dave
Random thought #42 Could it be something completely unrelated and not the PTU? Have you tried the dead PTUs on another car? Why I say that is because for a long time I blamed my PTU for stumbling and dropped cylinder problems. Every item it happened I would go and clean the PTU connectors and it would come good. Turns out it was actually my CAS connectors but by pulling off and cleaning the PTU connectors I was disturbing my CAS connectors just enough to fix the problem for a while. Once I cleaned those connectors all was fixed permanently. Just an idea Ab
The case of my S1 PTU is definitely isolated from ground BTW. May or may not be a reason for this. However bolting it to the body/chassis is going to ground it. Not sure about S2.
I found that excessive heat was building on the rear heatsink area of the PTU, so much so that 30seconds of the engine idling was too hot to touch ( >60 degrees C ) In the interim, I have reinstalled the standard PTU heatsink, which is the 5mm plate which mounts the ptu to the stock location on the timing covers. I've monitored it, and it seems to be going OK. There was no visible problems with the wiring, and I could not fault the motor or cause misfire through manipulation of the loom under idle.
All genuine AFAIK. I will look into it. I think someone mentioned they wanted to see inside the failed PTU? Well I ripped one open, and broke it in the process, but there was a black burn trail along the path of one of the surface mount resistors. Couldn't see too much detail under all the PTU Goo that they pack in there for insulation / waterproofing. Didn't get pics.
Hi. If you need to improve heatsink you could attempt to mount it on some copper flat/rectangle section. I make my own computer heatsinks this way. Well to start with anyway. Regards
