Hi, first thread i make here.

I'm the proud owner of a not so new Neon and i've a few issues with it, mainly the one in the title.

Sometimes while driving it just shuts off. No sputter, no loss of power, it just dies. I try to re-start it but no avail, cranks but doesn't turns on. Check the fuel rail and is pressurized, check fuses and relays everything is fine.

Then i check for the CHECK ENGINE light and doesn't lights up. I leave it there for a few hours/days and then it starts as if nothing has evr happened. The last time it did this was 2 weeks ago until today.

I'm most than sure is the ECU (or computer or whatchucallit) but i'd like to hear other opinions before sending it to the repair shop.

Thanks in advance.

 

Check crankshaft position sensor and the wiring going to it.

Are you getting spark during the times when the car dies? CPS can die slowly or quickly...

 

I've checked that sensor and apparently (both in physical form and throug scan when it's actually working) is fine, have to check more in depth the wiring though.

As for the second, yes and yes. There's spark even if you use some of that caned instant igniter it starts for a few seconds until it evaporates, since neither the fuel pump nor the signal to it works after it dies (I've checked the rail for pressure after it dies and it get's the residual pressure but after pressing the valve is empty obviously)

 

So you're not getting gas. So it may be the sending unit. Hitting the shrader valve it should spray out with some force.

http://troubleshootmyvehicle.com/chr...he-fuel-pump-1

 

No, the fuel pump is fine. I replaced it since it was in bad shape and had low pressure or not at all but wasn't the fault that the car dies randomly as it keeps doing now. Thanks for your input though . Any idea or suggestion is welcomed at this point.

Somewhere people have mentioned to repair or replace every wire that comes in/out of the PCM module and specially the ones that goes to the sensors.

 

CPS can fail... does little good to read info from it while car is running.
I have had CPS fail on me but car ran great 90% of the time. Once in a while the car wouldn't start, would start hard or fail while driving... but a few minutes later it would start again. That is until tge CPS completely failed.

After I replaced the CPS the car ran great. Than it started acting up again.
Then I took the wire harness out and rebuilt it. Some wires were frayed and melted together.

If you were getting fuel the car would start.... spraying starting fluid into the intake would not help.

Fuel, air, spark.
Adequate fuel pressurw at raul.
Air.. entering intake with no air leaks such as emmision hoses or intake manifold leaks.
If coil pack is providing spark to plugs.

With all the shoddy aftermarket parts on tge market.... new sending units, CPS. Yeah, it could be the wire harness too.
But you saying that your new fuel pump is working fine without seeing the actual pressure at the rail when the car fails... yet being able to start the car when spraying flamibles into intake.

That could be a relay in the fuse panel under the hood. A loose wire. A restricted fuel line or filter. A faulty pressure regulator.

Had a pressure regulator on my 96 fail. Sonetimes the car would start, sometimes it wouldn't. Sometimes she would just die on me. Bypassed the regulator and the car ran great for months until I got around to replacing the tank and sending unit.

It was the same with the CPS. Car ran good. Would drive 100 miles a day. Once in a while the the car would die on me. Wait a but and it would run. That is until it died and wouldn't start again.

It's tge process of elimination. Do visual checks on wires, fues, swap a couple of relays, pressure checks, resistance checks on plug wires and coil pack. Oull spark plugs, check gap and conditions. Look for oil in soark pkug tubes.
Spray engine gaskets and mating surfaces and vacuum hoses with brake cleaner to check for leaks. You'll hear a change in idle.

Have literally read through every post on this site in the first year of owning a Neon. Great for diagnostics. About every common problem, the car will have it after two decades.

 

Just to add. The times i did the starting fluid (no gas on the rail at all) the car ran, for a few seconds, that's when i learned that spark is OK so is the crankshaft sensor, since if isn't working there would be no spark at all, right?

I've checked the pressure after it dies and immediatly empties at connecting the gauge, then since the pump isn't working i can't measure it at all, until the car starts again, whenever that happens.

Yeah, i'm going to start to rebuilt the harness wiring, i've looked for one and no avail in the aftermarket (locally at least) and junkyards ask to damn much for one.

Thanks for all your aswers, they give much insight.