New and looking for some guidance

[rnacion]

Hey everyone, I'm new to the forum but have owned by Z for many years. However, long story short it has been parked for the last four years out of frustration. I was young and very uneducated with cars at the time, but am now much more comfortable getting to know the inner workings of my Z. It is a 1992 TT MT.

I brought my car to a mechanic to change the water pump and replace the timing belt in 2009. When I went to pick it up the vehicle was not idling properly. This led to being told by the mechanic that I needed a new E.F.I harness, (because it was so brittle and he had broken some of the plugs) I blindly ordered the harness and he installed it. Once again the vehicle was returned to me with a poor idle after the mechanic claimed he did everything right. At this point I was too frustrated to go on with the car and it was parked.

As of today I have revived my Z and am ready to figure out what is causing some problems. I threw in a new battery, some fresh gas, flushed the oil, and she started up fine. It had the same symptoms as when parked:
- erratic idle often leading to the engine dying when cold
- a rough wandering idle when warm
- hesitation/delay between hitting the pedal and revving
- loss of power (what I now know is safety boost)

I started reading. A lot of reading.

I cleaned the throttle bodies out, and adjusted the TPS (0.45 volts), cleaned the air filter/MAF sensor and plug which made a world of difference. The car now has no delay between the pedal and revving and the idle had stabilized, although it is now idling at about 1100 RPM when warm.

The car still tends to hesitate shortly after a cold start up. I verified that my Coolant Temp Sensor connections were clean, and verified that unplugged during a cold start the fan was off, and when plugged it stopped. Once warm the hesitation is gone.

I did an ECU diagnostic and got code 34, which was half expected. I decided that I would try to lower my idle before the code 34 which brought me to this discovery:


Two plugs leading to nowhere. The yellow one just to the right of the middle of the picture and the black one to the left.



This now leads me to believe that there may definitely be some issues in the way this harness has been installed. I am pretty sure I have determined that the yellow plug is for my AAC Valve.(Can someone confirm if aftermarket harnesses use the same plug colors?)

I looked into the IAA unit and discovered this:


It looks like the FICD plug is where the AAC plug should be, and there is no male connector coming from the FICD valve. Does anyone know if there is a way that I can go about getting the male plug and how to install it, or am I looking at buying a whole new IAA unit?

Also as for the black plug, can someone please help me identify this plug? I have been cross referencing between these two sites to identify it,
http://www.300zx-twinturbo.com/cgi-bin/ ... &total=133
http://www.z32photoguide.com/electrical.html

I guess I'll wrap up all my questions here:

- What else can lead to hesitation on a cold start up?
- Based on the pics posted am I right in assuming the yellow plug is for the AAC Valve, the FICD plug is incorrectly on the AAC valve, and the FICD valve is missing a male connector?
- Can I purchase just the male FICD electrical connector, or will a whole IAA unit be needed?
- What is the black connector that is not currently connected to anything?
- Which harness plug should lead to the detonation sensor (wire/plug colors if possible)? I have read that my code 34 could also be a plug mix up, but cannot remember which plugs to check and how to diagnose.

Thanks to anyone who took the time to read any of this rant/welcome/blabbering question post. Any and all replies are greatly appreciated. I'm very open to all suggestions and am hoping I can finally get this thing running the way it deserves to be.

-Ryan.

[Metacom]

Yes that yellow connector is suppose to go onto your AAC.

That mechanic probably broke off the connector to the FCID valve when trying to reinstall the harness. Im pretty sure its integrated into the unit, could be wrong. Wouldn't cost too much to get a used one off the classifieds here or over at tt.net. Articles that may help in removal/repair: http://home.swipnet.se/e-solutions/IdleTech.html and http://home.swipnet.se/e-solutions/IdleTech2.html

Its common for the intake VTC solenoid connector (usually driver side bank) to be plugged into the detonation harness.

I'm pretty sure that black connector is your detonation sensor connector. Trace the connectors/wires that are pluged into the VTC solenoids, if one of them runs down and behind the engine...its been mistakenly plugged into the det sensor connector. The proper wires for the VTC solenoid are easily visible at the top, back of the engine, they join into the main harness. The Det sensor harness is just one long wire from the det sensor in the galley up to its connector at the back center of the engine which then joins the main harness.

Have you looked at the FSM? http://www.300zx-twinturbo.com/cgi-bin/manual.cgi engine fuel & emission control system, starting at page 42 has a whole bunch of step by step procedures.

[nissanfreak12]

The black connector is a CA model for exhaust temp, or some emission thing. MOst cars do not have it or have it deleted. The det sensor is an oval grey connector, which normally gets mixed up with the VTC solenoids. It is also very common for the sub-harness on the det sensor to be broken, which causes a code. It is a very labor intense to replace the harness as it fgoes under the lower plenum and either you need to drop the transmission or remove the cam gears and everything else. MOst people just relocate until they need to do some work in that area.

[rnacion]

Thanks for the replies. I will take a look at it when the weather clears up a bit. I'll be diagnosing the sub harness once I confirm it is connected to the correct plug.

Is someone able to confirm the wire colors for the VTC solenoid and the Detonation sensor? More importantly the leads to the solenoid and sensor sub harness although it would be great if the EFI harness side could be confirmed as well.

[nissanfreak12]

This should help out, it shows what color all the wires are and where they go. I have used this many times with good success.

http://z32.wikispaces.com/ECU+Harness+Diagram