240sx Trouble

[USNDonahue]

My 1989 DOHC swapped 240sx is currently having trouble and I need help getting it fixed because I have tried just about everything with no success.

The Problem: As I drive down the road for no reason the motor will just die. I try give it gas with no luck or try popping the clutch which also doesn't work. When I try to turn it back over the motor turns over but won't start. When I checked the spark after it broke once I noticed the plugs weren't firing. Then anywhere from 1-20min later the car starts up like not a damn thing is wrong, and it will drive off. Finally I should mention that the car doesn't have to be driving for a while before it turns off, it once shut off after starting it in the morning and going about 100ft down the road.

Failed Solutions:

2 different coils

2 different ecus

2 different mafs

emissions check

coolant sensor check

timing reset to TDC

new plugs

grounds check,cleaned

distributor contacts cleaned

any ideas or anyone else have this problem then plz help me out

[elwesso]

have you checked anything fuel related??? Mainly fuel pressure... Thats a realyl weird problem... What id like to know is if the ECU is turning off when it cuts out... thats the operative question...

obviously something is "turning off" when it stalls and comes back in, who knows what it is...

have you tried anything to recreate the situation under controlled conditions?

[dickie]

check your relays and fuses?

[jdm_master_X]

have you checked anything fuel related??? Mainly fuel pressure... Thats a realyl weird problem... What id like to know is if the ECU is turning off when it cuts out... thats the operative question...

obviously something is "turning off" when it stalls and comes back in, who knows what it is...

have you tried anything to recreate the situation under controlled conditions?

i would check the fuel pump relay and circuit that connects to the ECU. it seems to me something isnt making good contact within the circuit causing the car to just shut down moments after start up. after it dies and you attempt to crank it over again, can you hear the fuel pump in the rear?

[C-Kwik]

Probably some sort of an intermittent short. I know I had one in an S13 I owned that would blow the ECU's Fusible link, shutting the whole engine off.

Then a wire to my coolant temp sensor on my S14 broke insude the insulation causing safemode to intermittently turn on.

These types of issues can be particularly hard to diagnose as they can happen on and off. Try pulling codes from the ECU to see if it might gove you a hint as to what components might be involved.

[USNDonahue]

Still not fixed I would check the codes but the E to DE swap requires the harness be spliced, so i can't pull any codes.

[USNDonahue]

Also, yes the fuel pump still works even when the car shuts off, all the fuses are good on the car I haven't checked all the relays yet but im working on it, I have a hard time of recreating the problem because I could let my car idle in the driveway for an hour and it may or may not turn off. and when it turns off I have about a 10 second window to mess it. Only thing i have found so far is the the coil doesn't fire when it shuts off

[Jasong]

There is a fuseable link in the fuse box under the hood that when it goes out there is no spark to the coil. Mine did it once but mine completly blew. Yours kind of sounds like a cold solder joint.

[Acecool]

Alternator is not charging the battery from what I am reading.

The reason your car will start up 1 to 20 minutes later, from what I believe, is that static electricity is recharging your battery, allowing it to start..

Have autozone or someone test your alternator and battery.

[carguy4207]

try checking the fuel pump and the fuel pump relay and also the fuel filter may be bad.