I have a Pearl White 1990 Nissan 300zx 2+2 VG30DE. On SOme mornings when its Cold outside, IT will only Crank and never fire up until it gets warmerr or sun comes out. Now on some Mornings i get Lucky and Crank it over at least 10 times then it will fire up. But I know im hurting something on the Engine or Fuel Pump. DO you think it could be Water in my gas tank and it freezes overnight or the Starter? Or Coolant Temp Sensor? Help if possible.

 

All problems are different sometimes, but I too had this problem a while back and couldn't figure it out. There is a 2 pin temp sender on the water neck on the engine. I pulled it off and found corrosion in the connector. My guess is it was giving the ecu weird values and was dumping fuel into the motor when I tried to start. Got a new temp sensor and cleaned up the pins and it started right up. never had the problem again.

 

I concur.. Coolant temp sensor is the most likely. ECU doesnt know how warm the engine is and throws off an algorithm it uses to adjust open loop/startup fuel trims.

 

When the ECU can't determin coolant temp it will automatically assume it's overheating.

I would check to see if the fuel system is holding pressure and if the fuel pump is pump is getting power everytime you hit the key.

 

Now would the Coolant TEmp Sensor also be known as the Engine TEmp Sensor located right above the Fan and left of Crank angle sensor??

 

Two sensors on the pipe the upper radiator connects to. The sensor on the left is the engine temp sender, the other is for the gauge.

 

Hey Guys,

I just posted in under the CAS problem and mine is exactly like mangrums problem. I ohm tested the CTS and it checks out within normal range for temp scale. I also have about 4.7 VDC coming out of the lead wire to the CTS terminal, which also sounds normal to what I have read.

Should I get a new CTS anyways or should a guy try using some resistors of different ohms to try and trick it? Resistors are cheap compared to the sensor, should the sensor not be the problem.

Mangrum did not say if he had raw gas smell after the no-start episodes and I do. I was wondering if mine could be too weak of a spark to over come the fuel being shot in on cold start.

I see it has been over a month since mangrum posted his problem and there is no follow up. If you read this Mangrum, please let me know if you had any luck. I even splurged 18 bucks to a "Nissan Pro" on a answer site and he seemed to know less than me, and I only had this car for 3 months.