87 Carrera - Started but cuts out.

[cygtoad]

OK, well I have tried two different DME relays, no dice. Then last night I replaced both the speed and reference sensors on the flywheel. The were pretty crappy and needed to go anyway.

After doing that the engine fired up and ran like a champ for just under a minute, and died (like someone took the key out of the ignition). While it was running there was no misfiring. Friends listened for any noise indicating that the sensors were placed too close to the flywheel. They heard nothing. So I am guessing that the sensor install was probably a success.

My next guess would be a fuel delivery issue unless someone here thinks otherwise. How do I test the pump? I have already jumped it from the DME socket and it whirs, but how do I test for pressure in the lines?

On another note I am wondering If I simply have a clogged fuel filter. I have one of those I can put into it tomorrow weather permitting.

Is there anything else it could be?

Thanks,

Matt

[ShakinJoe]

See the three plug connections by the cruise control module? Make sure they are all connected. The top one (white plug) fell off of mine and stalled the car immediately.

[cygtoad]

Thanks, Joe.

I will check that. The lower two are the were the reference sensors for the flywheel plug in. I removed all three and plugged them back in yesterday. I will make sure they are seated properly.

Not really sure what the white one goes to, but it has a frail looking line which runs abreast of the other two.

[ShakinJoe]

I think the top one is reference sensor for MAF. If your car turns over and you smell gas, chances are good this one was knocked off.

[JeremyD]

Start with the stuff you replaced first.

How's the cylinder head sensor?

[Don Ivey]

The top one (white) is the cylinder head temp. sensor. If it is the old one wire type, replace with two wire one from Pelican. I just did it and it's a nice upgrade as the one wire type gets it's ground from the sensor/head contact, and isn't always good. Good luck,

Don Ivey
'87 Carrera

[rcaradimos]

Originally Posted by Don Ivey

The top one (white) is the cylinder head temp. sensor. If it is the old one wire type, replace with two wire one from Pelican. I just did it and it's a nice upgrade as the one wire type gets it's ground from the sensor/head contact, and isn't always good. Good luck,

Don Ivey
'87 Carrera

+1
I think this could be your problem.

[Jascha]

+1 on the Head Temp Sensor...

-Disconnect harness plug from the white connector
-Connect ohmmeter across the white connector two terminals (if only one is found use engine ground)
-For cold (ambient 60-85deg F) resistance should be in range of 1.4 to 3.6 Kohms

[cygtoad]

Still, no start.

Thanks for the advice on the Head Temp Sensor. I replaced it with the two wire type recommended by Pelican.

Fuel pump?

[kidrock]

have you tried spraying some carb cleaner into one of your vacuum lines, then attempted a start?

[Por_sha911]

Air, fuel, spark.
Pull a plug wire and see if you get spark.
Swap out DME relay.
Fuel pump should hum when key is on. Pull an injector and check for fuel flow.
Get a multimeter and check your speed sensors (search for how-to).

[Don Ivey]

Had a similar problem and replaced everything, sensors, coil, dist. cap and rotor, DME relay, and finally discovered it was the ECU itself. I'd heard they were bulletproof, but when calling around for a replacement, turns out they go bad quite often. Make sure you're getting a signal out of the ECU to the coil; if not, could be the ECU. Hope not!

Don Ivey
'87 Carrera

[aston@ultrasw.c]

There's a test port on the LH fuel rail. It has an odd metric thread, I found an adaptor then hooked up a fuel pressure gage.

Here it is:

C1AK70 M12x1.5

http://www.hydraulic-supply.com/pdf/1121.pdf

It works great, no leaks.

[Quicksilver]

Check all the grounding points in the engine compartment. The one on the back drivers side of the intake manifold can cause this sort of thing.

Also check the connection for the engine harness in front of the engine. It is dead center on the top of the ledge in front of the engine where you can't see it. Make sure the connection isn't loose allowing it to kind of flop around.

The most likely path to a cure is to check the sensors, test the fuel pressure, and then the grounds. If you have someone who can test the DME then now's the time.

[rick-l]

Originally Posted by aston@ultrasw.c

There's a test port on the LH fuel rail. It has an odd metric thread, I found an adaptor then hooked up a fuel pressure gage.

Here it is:

C1AK70 M12x1.5

http://www.hydraulic-supply.com/pdf/1121.pdf

It works great, no leaks.

Trivia

Two recent failures on this BBS with these symptoms have been a pressure regulator and a fuel pump.

[cygtoad]

Originally Posted by kidrock

have you tried spraying some carb cleaner into one of your vacuum lines, then attempted a start?

Not to be a moron, but what vacuum lines should I do this too?

[rick-l]

Originally Posted by kidrock

have you tried spraying some carb cleaner into one of your vacuum lines, then attempted a start?

He says it starts but does not keep running

[cygtoad]

I have to agree with you Rick.

I am leaning towards a new fuel pump as a possible solution.

I get two clicks from the newly replaced DME Relay one when turning the key and the other when the key in the start position. So, I am guessing the fuel pump is probably getting power. I don't hear it running but It is hard to hear over the engine trying to start.

I jumped the pump at the DME relay socket and it whirs, but that doesn't mean it is building adequate pressure.

I don't think the 87 has the regulator, just the pump. Time to bite the bullet and swap it out.

[kidrock]

Originally Posted by rick-l

He says it starts but does not keep running

My point exactly. By spraying some fluid into an intake, you are able to find out if you have a fuel starvation issue. If the car doesn't start after spraying, you will have an ignition (spark) issue. If the car starts then dies, you now know if your motor is not getting appropriate fuel.

FWIW, this is the diagnostic I ran when I had similar issues about 6 months ago. It was intermittant, and progressed to the point that the motor wouldn't even start. When the motor refused to start, I sprayed into the intake and found my motor was fuel starved. I replaced the fuel pump, and have not had an issue since.

Cygtoad, you can disconnect either the top or bottom hose from your ICV. Spray a 2-3 second burst of fluid. Quickly and temporarily reconnect the hose, then turn your motor over. If it starts then dies, you are probably looking at replacing the fuel pump.

[cygtoad]

KidRock,

That is good advice and will help clarify the issue. Better to test than change out a perfectly good fuel pump when it could be something else.

I bought a can of starting fluid and will test tomorrow.

Thanks!