Z32 wont start unless its 70 degrees outside??? please help!!

[meet07]

Ok I have a freind that has has his 300zx for about 3 years now. For the last year that I know off his car wont start when its cold. I told him that I will ask around and that we will try to sort this grimlin out sometime this weekend.

-has anyone else had this issue before?-Can some one point me in a good direction?

Any input would help.

[BigTDogg (MA)]

Any ECU codes?

Does it crank?

[meet07]

I dont think it throws any codes... and it does crank it just got to be 70 degrees out. Meaning it needs to be warm. He just chagned the injectors thinking that was the issue but didnt work...??

He has a spare 300 that he has swapped many parts with but this nothing.

[txQ45]

coolant sensor...Two sensors on front of water pipe..1 on left side facing engine is coolant sensor2 on right side facing engine is coolant temp gauge..

[Zwicked]

Does it start if you put the gas pedal to the floor? If the Air Regulator is fouled and stuck shut it may not get enough air for cold start. Also check fuel pressure and test injectors.

[BigTDogg (MA)]

coolant sensor...Two sensors on front of water pipe..1 on left side facing engine is coolant sensor2 on right side facing engine is coolant temp gauge..

The one left would cause the engine not to start if not completely connected.

[meet07]

Thanks for the info. Ill pass it on but im sure he will tell me that he has replaced or checked that? He has a spare 300zx for parts...I think im gonna have to go over there with my multimeter and check some things out.

He was throwing code 55 which we all know what that means. The motor was getting fuel and flooding the motor. We wired fuel pump up to a toggle swicth.

[SLE-PR]

In regards to the no starting at 70 degrees, I have the same issue with a '90 NA. I am baffled as to why it reacts like this. If I leave it in the shop at 70* and take it out on a cooler day of say, 30-40* F, the car seems to run rougher even though the engine is at operating temp.and running 91 octane fuel. I have also checked the sensor on the front but to no avail. I am in the midst of doing more tests. Leak down is next, hot compression test gives me lowest cylinder at 120 psi, highest being 180 and the other four are 160 + or -.

I have gone through as many connectors as I can, checking, cleaning and putting dielectric grease on them. All injectors check out at about 12 Ohms and click when engine is running. I put Iridium plugs in and made no difference from OEM recommended ones. I pulled the harnesses off of each coil, one at a time (and reconnected) and found no difference other than rough idle until reconnected and of course, code 55.

I have combed many forum sites to figure this out and not able to find a positive remedy to this. I had a '86 z31 2+2 that started and ran like a top even in the cold Canadian winters. I am getting frustrated, as I am currently spending 20k, having a 700 hp motor built at Z1 for my '92 Z32J and hoping this isn't going to happen to it. It seems like it should be a simple fix but I am trying to understand and learn about the z32's to be able to do most of my own tuning and maintenance to save garage labor costs, as I live close too 200 miles from the nearest Nissan dealer and unable to find any local guys who care to or want to work on them.

In closing, I am sure hoping someone will read this and be able to help me. Also, is a person able to buy his own "Consult" or other type of unit to get a little more in depth into the cars for tuning and diagnostics?

Thanks, Jim