Well, since I replaced my plenum, had some issues with two of the cylinders. One of them was an intermittent failure, which was addressed by replacing series I ptu with brand new series II ptu. The other is the rear-most cyinder, near the firewall, passenger side. Coil packs connectors recently replaced. Tried swapping the coil packs with a cylinder that was firing, the coil pack is not the problem. I replaced the injector connectors with new ones, same way as the other 5 cylinders. It appears to be seated well on the injector. NOw, the puzzling thing is this cylinder was working before I yanked the plenum. I cylinder can't suddenly get zero compression such that it won't fire overnight, can it? I haven't got details on what the autoelectrician did, he asked me about the sparkplugs, I suggested they could be fouled. I really thought the new PTU would fix it (which it kinda did, but not this one cylinder). The autoelectrician is suggesting putting it on a dyno - how the hell will that help (aside from making me even poorer)? I know what the problem is, and I've gone to dyno's before and they've failed to diagnose really basic problems (like what I now know was an obvious boost leak). I seriously dunno what to do now. Anyone in the ACT got datascan/conZult or whatever and interested in scanning my zed? I read every tech article, took it to a professional and now I'm really at a dead end.
zero compression would suggest a valve not closing wouldn't it? or is that just a thought not a reality?, in any case i would be getting a second opinion from a different auto electrician, preferably one that knows what he is doing
The first thing I'd do is swap the spark plug from the "faulty cylinder" to another. When you're swapping them, look at the tips to see if they look the same. If the plug from the "faulty cylinder" is wet looking, it could be fouled". The one thing that can fail without warning is an injector, I had one fail without notice a few years back. If my memory serves me correctly, if you measure the resistance it should be 14 ohms.
did you drop a screw into the open plenum when you had it off?? yes you can drop compression in a cylinder overnight with such an action did you actually do a compression test though?
Couple of possibilities. Check your resistance for both you coil pack plug and injector plug on the loom side. Should read ~500 if I remember, you may have damaged them when pulling the plenum off. Did you replace the gasket between upper and lower plenum or use gasket sealent? Maybe you have a leak out of the intake runner for that cylinder which would cause a missfire if it was big enough. Injector failure possibility. Run the motor and place a screwdriver on top of the injector and the other end to your ear...should hear a definitive *tick* as it fires. Could have damaged a coilpack after you took it out and through it over you shoulder Try swapping them over with another one. And take out your sparkplug, have a look and see if it's fouled. Other than that as the others have suggested replace the spark plug
Check the PTU connection some of the new series 2 PTU wiring plugs can have one or more of the connectors looking like it's connected but it actually isn't... You might find that one of the wiring pins might have been pushed out of the series 2 connector where the series one wiring connector plugs into it. 2nd, do what was suggested with swapping the spark plug with another cylinder and see if the problem moves with the spark plug. Also reclean the injector connection. doesn't take much to disturb a connection that has some corrosion/green crap between the connections and ensure you retension the female connection so it 'grip's onto the male connector
God, I hope nothing fell into the lower plenum. I am going to check the plugs on that cylinder tonite, I didn't double-check with teh auto elec whether he did this (or indeed anything...). injector connector is new, but will re-wire to make doubly sure. The ironic thing is, I would have been happy to pay a professional to do it if there were anyone in the ACT that knew the first thing about zeds. In fact, I would have been happy to take it to Sydney but it couldn't be driven with teh coolant leak. Oh well. NOthing else for it I suppose.
You are doing a severe dis-service to both IB(Ian), and Zcar91(John), when you say that no-one in the ACT knows anything about Z32's. Both of these guys know the Z32 inside out, and both are the most giving, helpful people you will ever meet. Have you tried contacting either of them for assistance?
UPDATE - problem is sorted. Turned out to be a problem with the injector not seating on the first injector connector, (the one where the fuel rail kind of loops around back on itself). Which, to be honest, I triple and quadruple checked, but I was ><this close to pulling the plenum again and starting over. WIll post up some pics shortly, the engine bay is substantially improved. Also, CHILI - yep, when I said nobody knows anything about zeds, I was talking about paid "professionals". In fact, once upon a time when I was new to zeds, I had 2 separate mechanics tell me, variously, that I had a dead cylinder / dead turbine. John G (zcar91) figured out in about 15 minutes that it was, in fact, a boost leak and proceeded to help me pull the front bumper off and fix it. Ran perfectly (until the next thing went wrong...). And DOnovan (DonoRyan) even came over to my house one night when I got "stuck" trying to rip my plenum off. The thing is, these are private people, and to be honest I feel bad about imposing on them (at a tech day, maybe different story, but otherwise...) I have no qualms about doing as much as I can myself and paying a mechanic to do the rest, but the thing is at this point I'm probably better placed to diagnose zed faults (after reading the tech articles, like, 50 times over). It would be good if we had a specialist here in the ACT like UAS or something, I'd pay for the specialist knowledge, but what can you do. Gees you could make a bit of coin as a part-time z32 mechanic in the ACT.
