90 300zx NA dies when it reaches operating temp and cant start till cooled down

[z32partsmo]

90 300zx NA dies when it reaches operating temp and cant start till cooled down. I had to get towed the other day so Its time to fix this dirty problem. There is no engine light on or anything. Seems to run pretty well when it does run, but my buddy said it may have a slight miss to it. He also said that im getting fuel but no spark. After it dies I can crank it over and the motor will just turn turn turn all day long but will not start till it cools down. Could this be caused by bad sensor? I have a meter but do not know what to check. Any help would be great.. Thanks

[es.biggs]

I think this is a fuel injector problem. Some of them liked to stop working when they get hot, and cars wouldn't start back up until cooled down. I tried to find more info on this but I wasn't able to find any.

Maybe somebody else can verify?

[marty1mc]

1) You may also want to check your fuel pump circuits. I know my Acura had a similar problem (common on Honda's), where it would not run after it got hot. It would start and immediately shut off, not start again until cold. The problem with those is the fuel pump relay. It opens when it gets hot and the fuel pump doesn't run. The car starts initially from residual pressure in the fuel rail.

2). Check your PTU as well. If you can find one to swap, great. If not, try to cool it by popping it off and placing it in the freezer for a few minutes. Try it again. If it starts, your PTU is failing.

Some things to look at...

[dfddfd2]

Sounds like the coil is bad.

[marty1mc]

Sounds like the coil is bad.

The VG30DE (TT) doesn't have a coil. It uses 6 coil packs. The things that affect the coil packs firing are the CAS and PTU. Either of those could be suspect if the problem is spark.

[z32partsmo]

Hey I just that i would give you an update. The car has been dying on me a lot more recently. I'm not going to drive it anymore untill I get it fixed. I had to get towed the other day. So I rolled up my sleeves and got to work. Like you said the wire harness is a disaster. I didnt replace it, but I cut out all the butt connectors and soldered and heat shrinked everything to ensure perfect connection. I found several wires that pulled out of the crimped connections, so I was sure this was the problem, but it wasn't. lol So then I continued working and pulled all the coil packs. the two rear cylinder coil packs broke in half as I removed them. Surely this was the problem!! So I was pretty excited. Installed new Platinum plugs and 2 new coils for the rear cylinders. Time to try it. Cranked and started right up first time ran awesome idle perfect.Better than ever before. Big grin on my face. I fixed it!!! 15 minutes later it died. lol I was pissed. So I was wondering if I should replaced the knock sensor ? If its bad it may be sending error to ecu and shutting the car down. what do you think?

[z32partsmo]

That makes sense, do you know where the fuel pump relay is on the z? I cant find it I only found a fuse on passenger side near batterry.

[es.biggs]

A couple other things to try:

A guy on TT.net had a problem similar to this; turned out to be his fuel dampenerhttp://www.twinturbo.net/net/v...86767

Here's a little info on how to troubleshoot and what is called "ohm your fuel injectors":http://www.twinturbo.net/ttnet....html

[z32partsmo]

Ok I pulled the ecu and ohm read the injector pins OL on all pins!!! why would it be doing this? what would cause all the injectors to do this ?They are all good? Could this be caused by bad ground somewhere on motor? I used pin 58 for common read OL if I used cassis groung I would come up with a reading. I also had a spare ecu laying around so after I checked the pins I swaped out the ecu. the original one out of the car said 25 real big on it and the one I just put in said 24. Both came out of 1990 300zx 2+2 NA one was 5sp one was automatic. Is that the only difference?Anyways the car started right up and ran for about 35minutes then shut off. The car ran rougher with this ecu so I switched them back out to the original one. Checked for codes and got a fuel temp code 42. what do I do about this? and this causing the car to shut down?

[z32partsmo]

problem solved replaced CAS and its all good now. Thanks for everyones help