1991 Plymouth Acclaim delivery system issue 2

1991 PLYMOUTH ACCLAIM
76,000 MILES • 4 CYL • FWD • AUTOMATIC
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WILLYSP
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thanks caradiodoc!
i have spark and i had a helper to test the voltage (my helper already knew about those 2 seconds of voltage)

if the ASD relay manage the voltage for all those things (coils first at all) i m thinking that this relay is working properly (can the ADS works good for some thing and not work for another?) how can i check this ADS relay and if it has voltage on it? (if there are voltage in the ADS relay socket)

my last question is what is the hall effect? how can i check it? how can i replace it if its bad?
thanks again
wilson


[quote:4a640ed1be="caradiodoc"]First of all, you have to check for spark. If it is missing, the problem is not fuel related. If you do have spark but not fuel, you must first understand there will not be any voltage to the fuel pump when the ignition switch is turned on and you go back to test it. You must have a helper to turn on the ignition switch, or you must prop the test light or voltmeter where you can see it from inside the car.

There will only be voltage to the fuel pump, coil, injector, alternator field, and O2 sensor heaters for one to two seconds when the igntion switch is turned on, then it will go away. That will be proof the circuitry is good. If you hear the pump run for that one second, it is working too The voltage will appear again when the engine is rotating, (cranking or running).
If it doesn't, suspect the Hall Effect pickup assembly under the rotor in the distributor.

The voltage for all these things comes from the Automatic Shutdown (ASD) relay. The Engine Computer turns that relay on when it gets pulses from the sensor in the distributor.

caradiodoc[/quote:4a640ed1be]
Mar 7, 2010 at 11:17 PM
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CARADIODOC
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The Hall Effect Switch is a disc under the rotor in the distributor. It just lifts off, and has three wires attached. It's a very high failure item, but its his pulses that tell the Engine Computer the engine is rotating and to turn on the ASD relay. Since you have spark, the Hall Effect Switch is working as well as the ASD relay.

I can't remember about your car specifically, but many models use a separate fuel pump relay. Some of them are turned on BY the ASD relay. Some of them are turned on along WITH the ASD relay.

I can only find a '92 service manual. I know there are some differences from '91, but I think the fuel system is the same. There are obvious mistakes too but I think I can figure the circuit out. It appears the coils of the ASD and fuel pump relays are in parallel so they should both turn on at the same time.

Since you're already back there by the fuel tank, ground one lead of your voltmeter or the lead of the test light to a good clean part of the body, then use the other probe to measure the voltage on the dark green wire with the black stripe. That's the feed wire for the fuel pump. 12 volts should be there during engine cranking. If you find 0 volts, try grounding at a different spot. A poor ground for the voltmeter or test light could give a false reading and send us down the wrong road.

Let me know what you find there and whether you're using a voltmeter or test light.

caradiodoc
Mar 8, 2010 at 1:22 AM