Background: I have acquired a z32 and it is a 1996 with a early style TT motor. The ECU that came with it was a 1996 TT Auto, where as I have a manual tranny. I was getting a fuel smell in the engine bay and tracked down the smell to the injectors(stock) and pulled the plenum and replaced the o-rings and never could get it to run right (fuel smell went away). That was a year ago and it sat until recently. I figured out one or more of the injectors were stuck open and dumping a ton of fuel so I replaced the injectors. The car came with a JWT 1996 ECU tuned for Dual POP Chargers(DCP) and 615cc Nismo injectors in the back seat so I thought why not go ahead and replace the injectors with the 615's and hook up the JWT ECU. I completed the swap, calibrated the new TPS (long story), and fixed the couple of vacuum leaks I found. When I fixed the last vacuum leak, the engine went from idling at 1000rpms to dead. Restarted and idle is surging but it will run. Started trouble shooting the PTU and CAS and found some of the connectors are shorting but no matter what I do I cant get it to run correctly.

When I purchased the injectors I thought the ECU was for a single pop charger. I now realize that idle issue is almost certainly because the JWT ECU has the injector size cut in half and I'm still running 1 air intake. I just want to make sure I'm on the right track here before I go and buy the dual pop set up?

One more note to confirm my theory here. Spark is good, compression is good, and injectors are great as per an ohm test, and listening to them click away with a stethoscope. The engine will also not run above 3000 RPMS in neutral; however, if I switch ECU's back to the original tuned for stock injectors it still runs like crap at idle surging and what not but I can achieve RPMS past 3000. This to me seems like the smoking gun.

So my thought is I'm going to order new harness connectors for CAS and PTU, a consult Z cable, and the dual pop kit with the selien translator (use average setting). I just can't imagine the car ever running correctly with a single pop charger and a tunned ECU for Dual Pop.

Stock turbos with boost controller (10 psi).....shouldn't have any affect at idle.

How do you know that the ECU has the injector size cut in half? Without knowing anything else about the car it sounds like you may have the MAF signal being doubled (ECU set up for a dual intake with single MAF and a Dummy). Try pulling the Y-pipe off and installing the MAF on one of the sides and running it that way. Make sure you use some filtration on both pipes so you don't suck up something.

Good point. I just talked to JWT and they said I definitely need the the translator and a dual pop set up. They also said run the average setting on the translator.

NolimitZ32 wrote: ↑

Fri Oct 26, 2018 5:12 am

How do you know that the ECU has the injector size cut in half? Without knowing anything else about the car it sounds like you may have the MAF signal being doubled (ECU set up for a dual intake with single MAF and a Dummy). Try pulling the Y-pipe off and installing the MAF on one of the sides and running it that way. Make sure you use some filtration on both pipes so you don't suck up something.

When I spoke to JWT I mentioned the injector size and he said the what your were talking about with the MAF signal being doubled. Since I've been wanting to eventually build more power I've decided to go ahead and order the dual intake package from Z1.

Hopefully you're headed in the right direction. I'd test it out regardless by running the maf on one side and using a cheap auto-zone coupler like I described.

Tried the dual pop with a single MAF and the idle surged a little less but it was still running rough and definitely rich. I get the translator in today and I will post the results. I and sure JWT just doubled the MAF value for that ECU I have. I am nearly finished repairing the harness connectors for the PTU and CAS.....{rabbit trail} by the way, why does seem everyone refers to the CAS as a crank angle sensor when in fact it is a cam angle sensor?

Because they are referring to it incorrectly or just typing faster than thinking (myself included).

Ok so I got the translator today and no start. Unplugged the translator and went back to one MAF (second not plugged in) still no start. What I mean by no start is the engine turns over and a cylinder may try to fire every now and again but no luck. Thinking something with the CAS harness went haywire or maybe the PTU when i did the harness repair but I was extremely careful and double checked my work. Spliced with waterproof shrink connectors etc... Don't really know where to go from here. I did get the consult cable connected and working with ECU Talk and I get a couple of codes mainly the boost sensor and oxygen sensor. Nothing that would keep the car from starting?? The other harness I fixed was the AACV (yellow connector behind manifold Driver Side). Guess I will look at the FSM and see if I can get any leads.

Is there anything special about the wiring on the CAS sensor or the PTU. I noticed on the CAS sensor there is a white wire with 2 wires(insulated) inside and also some bare wire. It appeared that the bare wire didn't connect to anything so that's the way i wired it again but thinking back on it that doesn't seem correct. If it has a purpose what could it be as i count 4 insulated wires to the CAS sensor?

Don't know off the top of my head, check the wiring diagrams in the FSM in my sig.