Z32 TT, cranks but no start

[Roxa]

Last month I picked up a 91 300zx TT, 105k miles, original injectors and it had a few mods like a HICAS eliminator, JWT Pop Charger (single), JWT ECU, AIC/EGR delete, Apexi BOV's (Going to go back to recirc). A few days after driving it I was on my way home from the gas station and I hit the throttle and it hesitated, so i let off and eased on it for a few seconds, then hit the throttle again and it just died on me. I coasted into a parking lot and tried starting it and eventually after an hour just had it towed home. When I purchased the car I was told that it was running on 4 cylinders because 2 of the injectors were dead. Well I pulled the plenum, ohm'd out the injectors and 4 were open circuit so I ordered 6 JECS injectors and replaced those. Nothing has changed and here's the symptoms: Plugs are wet with fuel, plugs are sparking (pulled and sparked on plenum), if I try and start the car with the throttle open it'll kinda "chug" like it wants to start for 5-20 seconds and then die off. If I try and start it closed throttle It just turns and turns. I checked the ECU and I got a code 34. So I looked at the connection from the EFI harness -> subharness of the knock sensor and noticed one of the wires (the ground) was disconnected. I spliced it into the EFI harness for now but no change. I ordered some new NGK plugs just for the hell of it and are going to install them tomorrow once they come in. The PTU (I dont know if its v1 or v2, was spliced in a very odd way down toward the intake, so I'm not sure if its PTU or not. I included a picture of the PTU (There's a turbo timer on the car and an aftermarket alarm system (Viper) but im not sure if that would be the cause for the connections like that.)

On my list of things to do was replace the EFI harness but I'm kinda focused on getting this thing at least started for now. Unless for some reason changing the plugs magically fixes this issue I'm pretty stumped as far as where to go now. I was thinking the MAF sensor could be bad but even removing the plug to the MAF the car wont start. It really really sounds like it wants to start (with an open throttle at least) but just wont. If anyone has any idea's I'd greatly appreciate it. If any further information is needed I'll try and provide it.

P.S. Hi I'm new here! :O

[nissanfreak12]

The PTU is V2, it looks like he just deleted the subharness. The KS wire is only supposed to have one wire, one goes to the ECU, the other is the shielding so it doesn't pick up other engine noise.

When was the Timing belt last changed? If you have spark, fuel, air, all you need is timing. Are all the plugs wet with fuel and sparking?

[Roxa]

Honestly I cant tell you when the timing belt was last changed. It could be original for all I know. I'm about to go pick up my new plugs and install those. All 6 plugs were wet with fuel by the way. Could it be the CAS?

[t.mcginley.jr]

I'd say nissanfreak might be right about the timing being the issue.

A bad MAF, TPS, even a bad knock sensor (code 34) will cause it to run like crap, but shouldn't affect it starting. I'd say the CAS is okay because the plugs being means its getting fuel. The issue might be with the PTU, it's possible the unit itself is bad or one of the connections is bad. It looks like the PO only deleted half of the one subharness connector but not the other. You can try putting in a working PTU (used ones on ebay for ~$25) and see if it starts. If not, I would inspect the wiring for anything weird. Those look like crimp connectors, which aren't all that bad but soldering is obviously better.

If the wiring is okay and its not the PTU itself, then I would say check the timing belt, which requires pulling the front of the engine apart.

Btw, it doesn't start when you jump it either does it?

[Roxa]

I'll look on ebay tomorrow (currently working on an audio overhaul on my RSX so need to get it put back together tonight before work in the AM). I'll try and get one ordered but I was planning on calling some shops tomorrow and seeing what the price would be to get a new timing belt installed. I don't trust myself to completely install the belt right as far as getting the 1st cylinder to TDC. And no it does not, I actually just tried last night for the hell of it and it was still doing the same thing.

[t.mcginley.jr]

Ok so if it doesn't start with a jump you can pretty much rule out battery and starter, not that I think that's your problem but you never know.

Timing belt job at a mechanic can run about $1000-1200 on these cars because of labor.

[Roxa]

Looks like I'm going to be picking up a manual, a timing belt, and a case of beer next week and learning how to change a timing belt. Should I change the tensioner's out as well?

[Roxa]

So the OO just texted me back - the timing belt has been changed at 55k miles and 102k miles (105 current). Unless it jumped a tooth? I'm kinda dumbfounded at this point.

[nissanfreak12]

It could be possible the tensioner gave out. Did he change out the pulleys and the tensioner when he did the belt? If he just changed the belt, could very well have jumped a tooth, but if it did jump a tooth, something went wrong, for the most part.

Before you start throwing money into the car, double check the fuel pressure. Even though the pugs are wet, it may have a bad pump or regulator causing low pressure.

[Roxa]

Alright I'll do that, gonna go pick up a fuel pressure gauge tomorrow and see what its at, supposed to be @ ~43 psi correct? And where should I T into the fuel line?

[nissanfreak12]

After the fuel filter. Yes, 43psi.

There is also a FSM on the home page of the technical section, don't even bother with the crappy haynes/chilton manual, if they make them.

[t.mcginley.jr]

Online manual/FSM: http://www.300zx-twinturbo.com/cgi-bin/manual.cgi

If you look at the CAS on the front of the driver side timing cover, you can see that it has slots so that you can adjust it either way in order to adjust the timing. Is it turned all the way to one side? If so, thats a good indication that the timing is off.

[Roxa]

The 3 slots with bolts going through them? It looks like those are all in the center of the slot.

[Roxa]

[youtube]http://www.youtube.com/watch?v=cP19W99d878&feature=plcp[/youtube]

Video of the gauge cluster and 3 start attempts.

Second video, longer run.

[youtube]http://www.youtube.com/watch?v=lxqxW4XgKHM[/youtube]

[t.mcginley.jr]

So it does start, but doesn't idle correctly at all. Could be a bad IACV unit on the back of the upper plenum.

[Roxa]

Thats a fair to say yeah, if I dont hold the throttle open on startup then it will just turn and turn and turn. I'm going to go check the fuel pressure here in a few minutes (had to wait for the kit to come in from orileys). So hopefully I can rule that out. If that IACV is bad, can you just clean it out or when they go bad they're fried?

[t.mcginley.jr]

There's a way to test the IACV unit I believe. If you remove it from the plenum, you should be able to apply 12V to the two connectors (one is IACV, one is AAC) and you should hear an audible click. If not, it may be stuck or broken. You can clean them out but if the solenoids are bad then it's shot.

[t.mcginley.jr]

BTW mine is working that great either, my warm idle is ~1k rpm when fully warm. I've just been busy fixing other issues, like sticking calipers..

[nissanfreak12]

Check your codes again after you run the car until its warm, shut it down and recheck. Report back, poor idle could be a multiple of things. IACV yes could very well be a culprit, and it never hurts to clean it, like it was stated earlier. Just be careful disassembling it, they can break very easily.

[Roxa]

So I just tested fuel pressure after the fuel filter. When I would prime the fuel pump, the gauge read 0, but once i started cranking the car it took about 3-4 seconds for it to build up to a maximum of 47 PSI. Not entirely sure if thats intended or what.

I dont have a choice of when the car shuts off, it shuts off by itself. I cant keep it running.

[t.mcginley.jr]

It's either an air or fuel issue, your fuel pump might be getting weak or you IACV is gummed up and the valve inside is sticking. You could try pulling the hoses of of it and sprayed throttle body cleaner inside and then let it dry for about an hour and then spray WD-40 in both sides to try and lube it up.