Engine gradually lost power over past few days, now it starts for a few sec only

[Szabi]

It started with the car shaking as if not all pistons were working. Then the engine became less and less powerful, and could not rev up to above 2,000 RPM while driving (but it could go to 3-4,000 RPM when parking). Idle RPM went down to below normal, and sounded like the motor wants to die any seconds. And the last phase: now I can only start it for a few seconds (500 RPM max and then it dies).

This happened during the days when I was replacing radio harness and installed new speakers but I guess it has nothing to do with the engine problem (first I thought a ground had been disturbed).

This is really annoying, because a bunch of new parts were installed a few months ago and the engine had been running great since then. These new parts: spark plugs, injectors, fuels lines to the injectors, ignition wire set, lambda probe, microswitch (idle), fuel accumulator, rebuilt warm-up regulator.

I have fuel in the tank and I checked the battery, it shows 12.2 Volts. Any ideas highly welcome...

[Citizen]

Any ideas highly welcome...

My first thought would be loss of fuel pressure.

Yes, you might have fuel in the tank, and new injectors, and accumulator, but it still could be pressure. Have you actually looked inside the tank? Could be the FP pickup line is all clogged up with junk. Or, the FP could be failing even without being clogged up.

Thomas

...

[Jonathan]

This happened during the days when I was replacing radio harness and installed new speakers but I guess it has nothing to do with the engine problem (first I thought a ground had been disturbed).

This is where I would start. However improbable, if this was the only thing you know that was worked on or changed, I would still go over each and every area that may have been bumped, disturbed or changed while you did the stereo work.

If it isn't a physical problem in the fuel tank or elsewhere, then some wire or connection somewhere isn't doing it's job to keep your car running.

Perhaps start in the fuse and relay area behind the passenger seat and ensure everything is still snug and connected well. You might have inadvertently pulled the back out of one of the connectors while you were running new speaker or stereo wire.

[DMCMW Dave]

My first thought would be loss of fuel pressure.

Yes, you might have fuel in the tank, and new injectors, and accumulator, but it still could be pressure. Have you actually looked inside the tank? Could be the FP pickup line is all clogged up with junk. Or, the FP could be failing even without being clogged up.

Thomas

...

This is where I would look too. Stuff can plug up the screen a the bottom of the tank, and will fall off when you stop the car for a while and then go through the process again. You did not mention going into the tank or cleaning it (or the fuel system). How old is the filter? Was the tank cleaned?

The other thing that can do something similar is a kinked pickup hose, although in that case the pump tends to get really noisy when the hose heats up and kinks more.

[hmcelraft]

If the Lambda unit is not working it would run like it is starving for fuel. The speaker work you mentioned, if on the rears speakers, may have disconnected something - a ground or other connections.

[tom kish vin. 4357]

Had this happen 4 years ago in my truck, turned out my catalytic converter was plugged, might want to check.

[Szabi]

Thanks for all the comments. During the weekend I could do only some quick checks.
1. I wired the fuel pump relay, so it works all the time: http://specialtauto.com/delorean-par...lay-jumper.jpg. The pump sounds to be working fine.
2. I removed the fuel line from the top of an injector. When trying to start the engine, fuel was coming from the fuel line.
3. Checked an ignition wire with more (spare) spark plugs: no sparks, when trying to start the engine.
(4. No catalytic converter on my car, so it could not be plugged)

I am no expert, but logically I have to first have spark now, before checking anything else. Can the loss of ignition be the result of my work on the stereo and speakers? During those days I turned the ignition key several times to 1st position (without starting the engine) just to check what is working what is not working with the radio/speakers. Could this slowly kill something that is related to ignition? Remember, it happened step by step, from some non-working pistons and gradual power loss to current phase, when the engine does not start at all.

I did not really touch the relay compartment, neither I installed the rear speakers, so I guess nothing was disturbed in that area. I rather worked around and behind the radio. Before that, I removed the center console (that goes from the dashboard to the back of the seats), and during that I had to move a few inches the main harness that runs inside the center console. But if I accidentally disconnected something, why the engine lost power gradually?

[Bitsyncmaster]

No spark. You need a voltmeter to measure voltage on the coil power and ground terminals (just turn key to on). Normally the + terminal will be 4 to 6 volts to ground. Normally the - terminal will be about 1 volt.

The + terminal gets voltage drop through the resistors and car harness. The - terminal gets grounded by the ignition ECU and also has some voltage drop in the car harness.

[Rich]

No spark, eh?

Dave is correct.

And here is the DMC Factory Troubleshooting Chart reference post for guidance as well:

LINK: http://dmctalk.org...3142-Factory-Troubleshooting-Charts-Engine-Will-Not-Start

4 images embedded. First two are both Chart C1, Ignition. Seems like you are working on test categories #1 and #2 so far.

After you access each image click on it again to improve the resolution.