'89 GT Was Running Great - Suddenly Dead (No Crank)

[mgmuscari]

Today I started my '89 GT and drove over to campus. It started up just fine, and drove great the whole way (as usual). I parked, turned it off, and went to deliver some exams to a professor. 15 minutes later I came out, turned the key on - no start. The engine positively will not crank. When I turn the key to the on position I hear the fuel pump prime, the chime sounds, and everything seems correct. When I turn the key to the crank position, I hear the relay on the fender click, but the starter does not engage. Holding the key in the crank position causes the power to drain (voltage drops completely out of range, dome light dims). When this happens I can hear occasional rapid clicking, and a whirring that sounds like the starter trying to spin. The tach shoots up to about 600, wavers a bit, drops into the negative range . If I hold it for a while, I can smell something almost like a rich, partially burned fuel mixture (EFI is working I assume?). When the voltage drops, the chime starts to go crazy. Not only that, but after a few minutes of this, when I dis-and-reconnected the battery, the horn started blowing! (possibly unrelated - jammed it kind of hard to see if it'd start Back To The Future style) I pulled the horn fuse, same deal, no crank, no start. I ran a KOEO test and pulled codes 15, 81, 82, 84. 81-84 are EGR related and I don't give a crap (I don't have an EGR). Code 15 indicates "Failure in Electronic Control Assembly - problems with Keep Alive Memory." Is this due to the voltage drop? Perhaps the most important things that I can note here are: With the key off, I connected my DMM in series with the positive battery cable to measure current drain with battery off... this is negligible (on the order of mA). With the key on, I measured voltage across the battery. The battery reads 12.5v, and continues to read 12.5v while attempting to crank. The voltage across the starter relay also reads ok. Some friends of mine said they noticed a burning smell from around the area of the starter relay or maybe from down below when I tried to crank it. Touching the positive battery terminal to disconnect it I noticed that even after only trying to crank for a few seconds, the positive battery cable heats up (very hot). This indicates to me that there's a short somewhere. What's going on? Where should I look next? I have a relay that I'm going to swap in tomorrow, but if that doesn't work, I'm stumped after that... My car is currently sitting in a faculty lot, and while I do have a permit, I'm not sure how long they'll tolerate me keeping it there... help!

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[mustangsneverdie]

sounds like your solenoid

[mgmuscari]

Originally Posted by mustangsneverdie

sounds like your solenoid

Do you mean the relay solenoid on the fender or the starter solenoid that engages the gear to the flywheel?

[mustangsneverdie]

your yr. model only has the fender mounted solenoid

[mgmuscari]

Originally Posted by mustangsneverdie

your yr. model only has the fender mounted solenoid

thanks for the info... i'll try swapping this out in the morning. a friend advised me to check ground connections and check for shorts, so i'll try that, too.

[mustangman9798]

Sounds lie what happened to me. Try to jump the solenoid by putting a screwdriver (insulated lol) between the two screws on top with the key in the run position (I know seems obvious but i can be stupid sometimes). If it starts up then the solenoid is most likely bad but at least you can drive it home and fix it there.

[mgmuscari]

Originally Posted by mustangman9798

Sounds lie what happened to me. Try to jump the solenoid by putting a screwdriver (insulated lol) between the two screws on top with the key in the run position (I know seems obvious but i can be stupid sometimes). If it starts up then the solenoid is most likely bad but at least you can drive it home and fix it there.

Tried this and it actually killed everything until the key was turned off and back on.

[simpsonfan13]

i agree with your short idea. seems to me that the electricity is probably arcing somewhere it shouldn't. the fact that your hear the starter trying to engage tells me that theres current getting there but obviously not enough to fully engage it.

[88GTBLACK]

push start it get it home completely clean all the connections and run your hands down the wires check for rips, tears, etc.

[dreamer1uk]

Hi,

Is the Starter binding up? If the voltage drops below 9.6v during cranking, that could be a sign the starter is shot (assuming you have a fully charged battery) If all else fails, some auto parts stores will test the starters off the vehicle for free.

Hope this helps.