Help please....'94 NG900s starts and dies

2.3L FI engine 125K miles

Following a new battery installation and having the engine die and not restart after driving it approximately 50 miles the car was towed home for further investigation.

I ran a compression check to eliminate the possibility of a bad head gasket. I noticed that the #1 spark plug had a wet look to it and the other three did not. Compression was good.

The new battery went to 5.5v overnight with NO lights on and the key in the lock position. I disconnected the negative battery cable, charged the battery and reattached the cable. When contact was made to the post I heard a coil or relay at the right rear of the engine energize and a could hear a humming sound. Removed the negative cable and checked current. 1.5A draw.

After some experimentation with the ignition OFF, I determined that the #1 fuel injector is turning on when the battery is connected and there was a humming sound from a valve in a bypass hose that runs from above to below the throttle plate.

During subsequent checks I found the fuel pump fuse blown. After replacing the fuse I was able to start the engine with it dying after a short run, as if it ran out of fuel. The fuse blew again while testing around the #1 injector and the valve I mentioned above. I had not attempted to start the engine nor was the ignition on. I have been using a pushbutton switch to briefly connect the negative cable and the negative post of the battery.

I checked the internal resistence across the injector and it shows 14 ohms as does the #2 injector. I have the rear seat cushion pulled up and do not hear the fuel pump trying to run.

Not having a schematic I am at a loss to know where to look next (other than having it towed to a dealer for repair). I also dropped the panel under the dash to get to the relays but again with no schematic I don't know how they are wired.

Thanks in advance for any help. _________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

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Lou
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Well, that explains the dead battery.

The bypass hose valve is the Idle Control valve and this does contain a solenoid that hums when it is active.

Neither of these circuits (fuel injection, IAC valve) should be "alive" when the keyswitch is in the off position. This makes me think that, at a minimum, your key switch is FUBAR. AFAIR the control voltages for these devices come from the ECU, so in the event that you figure out what's wrong with that, you may still have other problems. Sounds like a good problem to bring to a good independant mechanic / troubleshooter. Schematics would seem to be an absolute requirement.

-Fred W

Reply to
The Malt Hound

I kind of discount the ign switch at this point because nothing else is acting up.

I went to the public library today and now I have copies of what I think are the pertinent circuits. I'll try to keep the group posted on what I find. Time to go back out to the barn with papers in hand....

Life just keeps getting better . . . . . . _________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

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Lou

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