Greetings Everybody. I was installing a water pump on my 92' B-250 and like an idiot I had not disconnected the battery. When I removed the alternator harness it touched something, shorted out, and there was a spark and the little pop that goes with it. I disconnected the battery and completed the water pump job and now the van won't start. I have fuel pressure but no spark. I put an OBD1 scanner on and only got two codes. "33 open/short in A/C clutch relay", and "45 open/short in overdrive solenoid". These kind of make sense because the van doesn't have A/C or overdrive. My question is, can you still get codes like these if the PCM is fried because of the short I caused? Is there a way I can know for sure the PCM is fried before I buy one? Someone told me these old computers can still put out codes even when they are bad. Thanks.
B-300
06-19-2009, 01:42 AM
If the processor is still intact the PCM will be able to put out codes.
Most likely the output driver for the coil has been blown out. It could also be the crank sensor or input circuit for it has failed... it controls the ignition circuit, the cam sensor controls the injectors.
alloro
06-19-2009, 10:53 AM
I'm sure that all you did was blow a fusible link, and now your ignition circuit is dead.
delivered42
06-19-2009, 10:07 PM
My extreme novice is definitely showing. Is the output driver part of the PCM? If it is, then that still means PCM replacement? Is a fusible link another way of saying a fuse in the box? I checked all the fuses visually and with a multi-meter. They are all ok. Will a bad crank sensor show up on an OBD1 scanner? What is an input circuit and how do I check that? Sorry about the novice. I'm really hurtin' financially right now and I really need to try to resolve this outside of a shop if at all possible. Thanks everybody.
stev
06-20-2009, 12:39 AM
A fusible link is a in-line fuse in the length of wire running from the device to the fuse box or device to device.
From Wiki ...
"A fusible link is a device consisting of two strips of metal soldered together with a fusible alloy that is designed to melt at a specific temperature, thus allowing the two pieces to separate.
Fusible links are utilized as the triggering device in fire sprinkler systems and mechanical automatic door release mechanisms that close fire doors in warehouses, etc. Some high-security safes also utilize fusible link-based relockers as a defense against torches and heat-producing tools. Automobiles also may utilize fusible links.
Fusible links come in a variety of designs and different temperature ratings."
Read this link on how to spot and fix a fusible link in an insulated wire-harness. :teacher:
http://www.wefixittogether.com/?p=25
Ahhh Ha!!! That fusible link is very interesting. I can't wait to check that out. Thank you very much.
delivered42
06-21-2009, 07:46 PM
I am sad to report that I found the bundle of fusible links and after careful inspection I am certain that they are all intact. I believe I am back to possible damage to the spark/output driver in the PCM. One will be available for me Tues. or Wed.
salesbig
06-22-2009, 01:09 PM
Check your main fuse box under the hood. The main fuse may be blown out. this has happened to me before on a different car..
alloro
06-22-2009, 01:59 PM
Check your main fuse box under the hood.
There is no underhood fuse box in a 92.
salesbig
06-22-2009, 02:06 PM
check main fuses.. you never know
delivered42
06-22-2009, 07:07 PM
I think Alloro is correct. The fuse box is behind the glove box door on the dash. I checked those first thing when I first had trouble. Visually and with a multi-meter. They all seemed to be ok.
