I'm working on an '89 maxima 4dsc with the 300z motor and 5spd tranny. When it's running it runs like a scalded cat, however once you've driven it and it gets hot if you shut it off it won't restart til it gets cooled down. We've replaced ecu, distributor, power transistor, coil, plugs, wires, engine temp sensor. the only code it throws is the detination sensor. We worked on it a long time, lost hope and shipped it to a nissan factory tech/ guru/ teacher/ // He couldnt figure it out. Any ideas? I REALLY WANT THIS CAR RUNNING AGAIN FOR MY MOM.

 

anyone?

 

What is present as fault is on:
- Spark? Tested with a grounded spare plug?
- Injectors do click (when distr out & rotated, ign on)
- Fuel hose stiff =pressure ok (pump on, pumping sound heard?)

 

injectors click fine,fuel pressure present and good,no spark from the coil for 10 minutes to a spark plug grounded or to a volt meter looking for weak but present spark,then you will see 1 spark, then2 then more until it finally fires up after about a minute from the 1st fire,then it runs great until shut off again after driving, there is the proper voltage at the power transistor, you can watch the distributor build the 5v square wave "one for each cyllinder" if you rotate it by hand, i have not checked the 360 degree marks with a scope though but i did substitute another distributor and it did not fire the coil either. engine rotation speed is good, the signal path from the power transistor to the ecm plug and coil plug checks out good "no opens". voltages at the coil,ecm and distributor are good.computer shows no codes on self diagnostics [the lights on the side of the ecm], only the detonation sensor code stored in the hard codes.shows up with a code reader. engine does not over heat when run and shut off, temp is normal. if you just start it and let it run for a while it will restart fine most times, but if you drive it during anywhere it will not restart.

 

"...there is the proper voltage at the power transistor, you can watch the distributor build the 5v square wave "one for each cyllinder" if you rotate it by hand, i have not checked the 360 degree marks with a scope though but i did substitute another distributor and it did not fire the coil either...."

Did u swap:
- Transistor
- coil
- all 7 hivoltage wires

Theres the campos sensor giving those square waves, input to ECU about engine rotation. ECU then drives the transistor. If transistor is really driven, then I cannot understand anythin else than coil & transistor problem. You may try to measure such transistor/fet(?), but u can never be sure, especially in intermittent heat related problem. Swap. Also coil may have intermittent heat related cut.
- buy freezer spray from electronics shop, spray liberally on suspect spots after warmup problem. If u hit jackpot, engine starts...

Some issues, possibly not related:
- Early model 3gen ECU's did not allow startup if the mentioned campos signal was missing.
- Distributor grounding is critical (see page10) http://www.cardomain.com/ride/748507/1
- maxima distributor caps, even new ones are quite often cracked. Lacquer spray on both sides (see p.12, not on electrodes)
- some electronics problems come from aging connectors: http://www.cardomain.com/ride/748507/14