Warm starting issues

[709Z32]

Hey guys, im having a persistant issue thats been bothering me. I have done plenty of research on this car, and need a little guidance.

My JDM tt always had a starting/running issue since i got it from japan. Dug into it, had code 34. Cleaned terminals, reset codes, never returned. Started fine about 3 times, after that hot or cold it would hesitate on startup. Ran codes, code 21, checked all wires, found out i had a bad ptu, and the connector pins were all corroded apart. Replaced ptu and wiring back to where it joins the main harness. Hesitated on startup still, but runs great.

Checked codes, code 13. checked, signal good, ground good, ect reading out of range. Tried to start without it plugged in, starts perfect. Went next door to nissan at work today, managed to get one in stock! Came home, installed it. Started several times on cold start waiting different lengths of time. Starts awesome. Warmed up, checked ignition timing, 15 degrees. shut off, started, annnddd hesitate. still much much better then it was prior to ect replacement, but it chokes for about 2 or 3 seconds bad.

Unplug ect, starts fine every time. If i let it sit for a few minutes in between warm/hot starts it starts pretty good, not perfect though. Unplug ect, perfect starts. All of this is in between resetting codes. When it cools down it starts perfect again.

So I ran the oxygen sensor test, the blinking of the light are long and far between. The left will stay on for about 2 seconds, go out for 3, 4, 5. The right side has better response, but still sluggish. I have nothing to compare it to, but i feel like thats not right. By rights it should blink almost constantly for very very short periods of time. I also get black water/unburnt fuel out of my right tailpipe. Its obvious i may have bad oxygen sensors, but would that really cause that bad a hesitation on warm startup in these cars?

My prvr is already deleted. I also have a bad fan clutch, but that wouldnt make a difference. My very cold start ignition timing is 40 degrees. Sorry for the long read, any advice or guidance from some people whove been down this path would be great! It seems like im going in circles replacing and testing, it runs so well when started compared to when i got it, and with every fix im getting happier and happier with the car and how it performs. Thanks in advance for any input.

[evildky]

How is your TB's, IACV and TPS? I can't help but wonder if either the chts isn't closing enough or if someone adjusted the TB stops to not close completely. Basically when you unplug your CTS on a warm car it starts better than if it were plugged in? This would cause it to run richer than it shoud whihc would lead me to think that perhaps it's getting additional air it needs to make up for.

[709Z32]

tb operation is good. I adjusted that when i got it cause i noticed the nuts were loose on the cable.My iacv was cleaned and tested and seems fine. Ive started it a few more times since yesterday. First start it only stumbled for the first second, and actually started good. If i let it sit 15 minutes or more it will start with a small hesitation, but restart after its been running it will take 2 or 3 seconds to run good. I did a boost leak test back in july, and it passed. Ive done allot of work since then and had some of the plumbing apart, but it should be fine, i know its all tight. it idles at normal idle, and runs smooth.

Im going to check the tps and oxygen sensors tomorrow because i left my meter at work. This car was messed with by a a shady guy in japan, ive found some pretty bad "fixes" for things. I was going to delete the egr and do some other things, but i want to solve this issue before i go any further.

[elecfus]

after your PTU died did you check your coilpack resistance and clean your spark plugs?
if your PTU fails, your spark plugs will be dirty.

so to summarise:
a few months ago:
code 34 -detonation sensor
code 21 ignition circuit
replaced PTU and corroded connectors
code 13 - coolant temp sensor
replaced cts
irrelevant

>I get black water out of my tailpipe, left bank has worse performance than the right.
coolant is getting into your exhaust. probably needs the left head resurfaced and gasket replaced. might also be a crack.
do radiator and cylinder compression check.

[evildky]

tb operation is good. I adjusted that when i got it cause i noticed the nuts were loose on the cable.

You adjusted the cable or the stops? There are stops at each TB you need to make sure each throttle plate is completely closed when no pedal is applied.

[DCaff300ZX]

tb operation is good. I adjusted that when i got it cause i noticed the nuts were loose on the cable.

You adjusted the cable or the stops? There are stops at each TB you need to make sure each throttle plate is completely closed when no pedal is applied.

This, and be sure the little nuts are tightened properly which can be difficult. My NA also could be adjusted I found so the linkage would bind slightly and stick open a little sometimes, jury-rigging from some emissions fools I foolishly let fool around with my Z before I knew better a year after I bought it.

Your story is also reading frighteningly like my car problems went, and which when all was said and done resulted in a complete external engine rebuild and turbo replacement. Some jackass carefully hid some stupid boost raising isht that combined with a frozen turbo, bad IACV/corroded connectors, bad PTU sub-harness and freak wiring connection issue at the same time, all resulting in bad idle and eventually no boost and unreliable running complete with O2 and EGR codes.
TOTAL disaster...hope you do better!