1994 Altima Shuts Down

[nicoy2k]

I have a 1994 Nissan Altima. It has about 83000 miles on it. It is a 2.4 Lengine with a manual transmission and was purchased used about a year agofor my younger son to drive. It has an intermittent (more prevalent nowthan before) problem with the engine quitting either while sitting still ordriving down the road. The engine just shuts down and the tach instantlydrops to zero. I suspected an electrical issue with the ignition system. Ihave worked on it several times and have replaced the distrubutor twice(for the cam position sensor), the ignition coil twice, the powertransistor once. The problem seems to occur when the vehicle is has beenrun for a while and is hot. Once the problem starts, it gets worse fairlyrapidly until the engine will not start unless it is allowed to sit for along time (several hours). I had a dealer perform the diagnosis for me thefirst time and they said the cam position sensor was intermittent and thecoil was weak. That worked for a while, then the problem started again. Thefault codes indicate that the ECM isn't receiving signals from the CPS. Ihave tested the harness and connectors for continuity and they appear fine.I now suspect that the ECM is getting hot and failing, but I am not sureand don't have a good way to test this theory. A replacement ECM is about$300 and I don't want to keep spending $$ unless I'm fairly sure I can getit fixed once and for all.I need HELP!!!I've attached the wiring and voltage information for the ECM that was created to troubleshoot the problem. The numbers in the off, on, run, stall cells at voltages.

[574-240sx]

I had the same problem in my 97 maxima. Turned out to be camsaft poisitioning sensor. I put a new one in and fixed it. It sounds like a ground problem in the main harness. I would start checking ground and wiggling the harness when the car sit off. It sounds like a broke ground in the harness. You might be able to pick up a used ecm off ebay for cheap.

[s13sr20chris]

thats a fantastic chart you have there. let me tell you a simple test for the dist circuit. run the car untill its good and hot. once its shut down and will not restart pull the dist out and leave all connections plugged in. with ignition key on, turn dist and see if injectors start clicking. this indicates that there is a cam sensor signal going to the ecm and the ecm is taking action. if not it indicate some sort of fault with the dist and ecm. now let me say that your altima is famous for three things(causing a no start). 1)starter(obviously not the cause)2)fuel pump(tends to go out once and for all)3)distributor/cam position sensorthe last if known to fail when hot. some guys at my shop will test drive with a gallon of water in the car to dump on dist if the car shuts off. when they dump the water she fires back up and they drive back with a good diagnosis.