New owner to a Z32 Vert...have a few questions

[punkncat]

Hi fellows, I just picked up a 94 300zx vert (N/A). She has been engine swapped at the least, possibly harness swapped, don't really know. Body has 190K, engine is swapped and claimed to be a 160K engine. The timing belt looks good and it runs strong* I have a couple of different things I would like to ask about, so I will break it up.

A) The harness and car have a spot for a sensor at the end of the passenger wiper area of the rear engine. IIRC is is a temp sensor of some kind for a california model. My current engine doesn't seem to have that sensor, or even a place for it to have been. The car is throwing codes 13 and 35 which are both temp sensors.

B) The car has a very high idle most of the time and uses a great deal of gas unless I unplug the sensor above the "fail safe" idle control. I think it's called the IAA or something like that. When I unplug it the car idles well aside from stall off high revs, uses a lot less gas, but seems to have a great deal less power...if I read and understood the manual correctly then unplugging that sensor would send the system into failsafe and possibly causing it to throw the codes above? (I could be trippin')

C) How do you access the ABS Controller in the 'vert model? It is not in the trunk over the wheel well. I can see the lines under the car and only see a little port hole behind the passenger seat.

And lastly, is the door skin for a coupe the same as the door skin for a vert? Not the frame, the skin.

[RubyRed300ZX]

A) Only California models had an EGR Temperature sensor. The ECM you have in the car must be for a California model, I would presume, to know that there's no sensor connected. The sensor for the California models is located just above the EGR metal tube (driver's side of the EGR valve). Best solution might be to rig up a way to fool the ECM. Send back 0 - 1.0 volts at 85.3 K-ohms. Could buy a California EGR, but you would have to pull the engine to install it.

B) Should probably pull and clean the IACV assembly.

C) No clue, have never looked for it. I would have thought , as you seemed to have searched, inside the trunk on the passenger's side.

D) Door skin is the same as a base model 2+0

[punkncat]

Thanks for the reply.

The impression I get is that the car thinks it's cold all the time and is running on "choke" as it were. I don't know if that is even a possible condition, it's just what it acts and runs like.

Would it be possible to source a new CPU from a non California car and plug it in location under the passenger floorboard? Are the harness' the same aside from the additional plug (or two)?

[punkncat]

Just wanted to mention that with the help of your post and deco's site I was able to fix my issue in about $12 in parts. A new sensor and some resistors cleared the CEL.

[Ziggy1621]

Cheap fixes rock!!! and Welcome to Nico!

[DCaff300ZX]

Regarding the idle issues, I'll toss this out there- the IACV (Idle Air Control Valve) is the entire assembly that controls the idle air for the engine, and which includes the IAA valve you mentioned which is part of the PCV hose system at the back driver's side of the engine and where air enters the IACV.
I've had a similar situation as you mentioned with my TT during the colder season, my Cali '93 TT definitely acts as you mentioned with lost power and odd idle pattern until the ambient temps rise to around 45-50 degrees, and the car really finds a lot of lost power but still idles erratically. Even after a thorough cleaning and adding non-broken/corroded old connectors it has begun to go crazy again as the temps rise.
After the good cleaning and lubing with WD40 failed twice I am assuming that the IAA has failed or is erratic (known issue), and am replacing the entire IACV with a good used one that has all new connector posts while also replacing the wire connectors and harness, about $200 total costs.
This may well also be your issue, you can read up on the IACV/IAA in the FSM or in some posts on TT.net.