91 Park Ave. Won't Start After Reverse Jump Connection

I used my 91 Park Ave's battery to jump start my '95 LeSabre the other morning. In my foolish haste, I accidentally reversed the connections on the '91 temporarily. When I tried to hook up the last cable to the ground on the dead car, it sparked, which told me I'd reversed the cables on the '91's battery. I fixed the reversal and went ahead and jumped the car no problem. Now here a few days later, I try to start the '91 for the first time since then and it won't start. I'm thinking I've damaged something by having those cables reversed even for just a split second, because the car was starting and running fine in the days leading up to then.

When the mistake and sparking at the '95's neg. post happened, it did not cause the '91's engine to die or run poorly. I just went back over to the '91, fixed the cable reversal, jumped the '95 and turned the '91 off. The '91 was running when I started hooking up the cables. Here's how I had it reversed:

'91 "Good battery" '95 "Dead battery"

+ post: ---- black cable ---- : - post (last connection made, sparked)

- post: ----- red cable ----- : + post (next-to-last connection made)

The '91 will crank fine, but there does not appear to be any spark since a timing light on a plug wire doesn't flash as expected when cranking. I checked fuel pressure at the rail just to rule that out and got 42 psi, plus I can hear the fuel pump prime in the tank when I turn the key on.

I went through and checked all the fuses I could find (on the dash, under the dash on the driver's side and at the relay center under the passenger side dash. All the fuses look OK. I put the battery from the other car in temporarily just to see...it made no difference.

I'm looking for fusible links, but haven't figured out where those are yet.
I also thought maybe the VATS got screwed up somehow, but I would think if that were the case, the engine wouldn't even crank.

Maybe I've whacked the ECM, but if that happened, I don't see how the engine would have just kept running when the battery cable reversal occurred. Hooked up an Auto X-Ray scanner to the PCM / computer and at first it didn't want to communicate. After a couple of tries it did...maybe the connection at the diagnostic connector was not secure. There were no stored or active DTCs / fault codes. I believe the fact that the PCM can communicate indicates it has power and ground.

I don't know if it's possible to have damaged the crankshaft or camshaft sensors such that the ECM can't set up its spark timing and get the engine going.

Any tips (besides the obvious: "hey, hook up the cables correctly!" :shakehead) would be most appreciated.

Well, after looking over most all the wiring, fuses, etc., it was learned that the local auto parts store has the ability to test ignition modules. (I was not aware they had this capability!) I removed the coil pack and took the ignition module down to the store. It failed five of the six test steps. They offered me a new one at $209 (Borg-Warner), but since this car isn't my daily driver again until cold weather comes back, I thought I'd look around at options where I might be able to get one cheaper. (salvage, eBay, etc.) Turns out they can order an aftermarket one for $94. Might not be able to get much cheaper than that, but I'm going to look into it since I don't need to be in any real big hurry.

So if the tester was right and this module *is* bad, then I think it is pretty clear as to the cause and effect...the reverse battery connection, even though very brief, was enough to damage the module but not blow any fuses.
A very costly error on my part, certainly in troubleshooting time and effort if not in monetary terms. (Assuming the module is all that's wrong, that is.)

A couple of other observations... that last hard-to-reach 11mm nut on the ignition module's third mounting stud seems like it is just there for nuisance purposes. I had one of these off another 3.8L V6 Buick once, and it only had two nuts holding it on. Obviously whoever was there before me thought it was enough of a pain that they didn't think it worthwile to put back on.

All of the wiring inspection did yield one important find, that being that there were some bare wires at the camshaft sensor connector. Apparently over time the oil (perhaps power steering fluid, since that's almost directly above it) and heat have damaged the insulation there. Electrical checks did not reveal that any of these wires were shorting to each other or anything else, but nonetheless, they need corrective attention to prevent future problems. I've never seen automotive wiring this severely damaged by fluids before. I thought that wire insulation would ward off just about anything a car could hit it with...not so, apparently.

timrice-

I updated my post '1992 Olds 88 Dead after attempted jump start.' Hopefully it will help, but I think you have got the problem nailed. And that third nut yea, I tried for way too long to get it back on with no success. I just made sure the other two were nice and snug, I don't know what the trick is to get it back on.

Well, after looking over most all the wiring, fuses, etc., it was learned that the local auto parts store has the ability to test ignition modules. (I was not aware they had this capability!) I removed the coil pack and took the ignition module down to the store. It failed five of the six test steps. They offered me a new one at $209 (Borg-Warner), but since this car isn't my daily driver again until cold weather comes back, I thought I'd look around at options where I might be able to get one cheaper. (salvage, eBay, etc.) Turns out they can order an aftermarket one for $94. Might not be able to get much cheaper than that, but I'm going to look into it since I don't need to be in any real big hurry.

So if the tester was right and this module *is* bad, then I think it is pretty clear as to the cause and effect...the reverse battery connection, even though very brief, was enough to damage the module but not blow any fuses.
A very costly error on my part, certainly in troubleshooting time and effort if not in monetary terms. (Assuming the module is all that's wrong, that is.)

A couple of other observations... that last hard-to-reach 11mm nut on the ignition module's third mounting stud seems like it is just there for nuisance purposes. I had one of these off another 3.8L V6 Buick once, and it only had two nuts holding it on. Obviously whoever was there before me thought it was enough of a pain that they didn't think it worthwile to put back on.

All of the wiring inspection did yield one important find, that being that there were some bare wires at the camshaft sensor connector. Apparently over time the oil (perhaps power steering fluid, since that's almost directly above it) and heat have damaged the insulation there. Electrical checks did not reveal that any of these wires were shorting to each other or anything else, but nonetheless, they need corrective attention to prevent future problems. I've never seen automotive wiring this severely damaged by fluids before. I thought that wire insulation would ward off just about anything a car could hit it with...not so, apparently.

Do your self a favor and find a you Pull it yard or LKQ... Find a 3800 Tuned Port Injected 3800 from 93-95 and undo the 3 bolts on the bottom of the module and take the whole unit coils and all...

This would be the Delco Type 2 system and is a direct replacement for the Magnavox system on your 91.... You may be able to get away with the Type 2 System for decently cheap if you have a U pull it around you..