84 300z runs rough at startup

[chilinetc]

I installed the engine in an old datsun. It runs rough until it warms up. It's a custom job and the donor car is long gone. Thier is no way to put a code reader on it. I'm thinking it's a sensor or something. My manuals say nothing about it.

[evildky]

you can check the codes at the ecu, these cars are OBD 0

[chilinetc]

I'll have to check but I'm pretty sure I don't have the connection. when we installed the engine that wasn't on our list of things to keep. It's in an old datsun pickup that did not have any computer stuff. Was hoping someone would know buy experience instead of a computer reader.

[AZ-ZBum]

I'll have to check but I'm pretty sure I don't have the connection. when we installed the engine that wasn't on our list of things to keep. It's in an old datsun pickup that did not have any computer stuff. Was hoping someone would know buy experience instead of a computer reader.

It doesn't take a connection. You turn the screw and read the lights.

Download the FSM here:
http://www.xenonz31.com

Code checking instructions here:
http://www.xenonz31.com/ECUcodes.html

[chilinetc]

Thanks for the info I'll check it out.

[nismopu]

Depending on the codes that popup they can have you chasing your tail. The best thing to do is after wards test each individual component per the fsm instructions that you were given error codes for. Sounds like CHTS to me just from the simple description.

[chilinetc]

That's basically what I tried to do but I couldn't find the corresponding componet that went with the code. So I still don't know what the problem is. If it's a sensor it's either not installed on this engine or is hiding really well cause going through the manuals to match the codes I can't find most of the components. You mentioned a CHTS? don't want to sound dumb but... what is that?

[nismopu]

Chts: cylinder head temp sensor.
Its burried behind the drivers side cam gear and requires a bit of skill to get to if you have never done it before. Its best to ohm it out and find out if its within spec or not. You can do that at its black plug located on the passenger side of the intake manifold.

[evildky]

A bad chts generally causes the car to have a hard time on warm starts and can idle so rich it actuallky stalls the car. What codes are you getting?

[chilinetc]

It's starts fine cold or warm. Once you put it in 1st and take off it runs rough til it warms.
I got 4 codes 13-cylinder head temp circuit I couldn't find it but know now where to look.
23-Throttle valve switch (idle switch) circuit not sure where this is either
31-local signal circuit not used
41-Fuel temp sensor circuit the same here couldn't find it in the manual or on the engine

[nismopu]

Fuel temp sensor circuit doesn't do much of anything but its located on the FPR itself and is a single wire sensor.
Idle switch refers to the TPS and can cause similar symptoms but its most likely out of adjustment or has dirty contacts.
Code 31 not even worth investigating unless any of the sensors it was giving you codes for have broken wires or bad grounds(tps for example)
My money is still on the CHTS though, lol!

[evildky]

How are you plugs wires, cap and rotor button? What you describe sounds like a misfire situation, hopefully it's simple but it could also be a burnt vavle or cracked valve seat. Lets hope clearign up the codes improves the situation. The chts and fuel temp codes both cause a rich condition which could cause the miss but generally it gets worse when it warms up.

[chilinetc]

Plugs wires cap and rotor are all brand new. this only happens remember when it's cold once it warms up it runs great. I haven't had a chance to find the chts thing. not to mention I don't know where the fuel temp sensor is.

[evildky]

nismopu's post told you where the fuel temp sensor is (it's in the FPR right out front has a single wire hookup)

a cracked valveseat could heatup and close the crack once it warms up, again, knock out the codes first.

[chilinetc]

I have tested the fuel temp sensor and it does test bad but at this time I have not been able to find a replacement any Ideas? I also want to test the chts but have not found the specs on what to test for. I've been trying to down load a factory service manual but so far no luck. does anyone know how to test this sensor and what it should read? and does anyone know a site to look at or down load the factory service manual?

[nismopu]

http://www.xenonz31.com/reference.html