Experiencing electrical failure

[Shinto]

Last night I was on my way home and the "Service ABS" light came on followed a minute later by another about the SRS, then the SES light a few seconds later. I raced into the nearest parking lot and shut down. It wouldn't restart. I had to have my wife come out with the jumper cables and jump start it. It ran fine for about 2 miles and everything started happening again, this time I lost my headlights and dash lights and the engine began cutting out before shutting it down and jumping it again for a good 20 minutes. I started the car and ran as fast as I could and got it about a block from home before everything went dead shortly before the engine died and I had to bring to the side of the road dead stick. (Ironically I went right past a Sheriff's deputy at 45 mph in a 25 with no lights on to save power and he didn't seem to care...)

Strangely, the battery light never came on.

I highly suspect the alternator is dead and the engine was running off the battery until it ran out of juice. Anyone else experience this? Any other alternatives? Somehow, I'm not convinced its the ECM.

Also, I saw either here or another forum some time ago where someone came up with a method of swapping in a much cheaper L-98 or LT-1 alternator. Can someone point me in the right direction here?

[Shinto]

Just a quick follow up -- After charging the battery for a few hours now, voltage at the battery terminals is 12.27V with the engine running and 12.54V with the engine off. This seems to confirm my suspicion that the alternator isn't working and the engine is running off the battery. So how do you get to the alternator?

[tccrab]

Looks like you've got a plenum pull in your immediate future.
I've got extra gaskets & the right tools.
I'm up in Folsom, drop me a call if you'd like some help.

TomC
'90ZR1 #792

[GOLDCYLON]

Well im not sure about a plenum pull but I do know the Air cleaner unit and Air Horn and S-belt need to be removed. Are you sure TC I defer to you since I have never done the alternator job before but I sure gave that area a good look a couple of weeks ago when I did the Water pump ;)

[Sgreg]

Well im not sure about a plenum pull but I do know the Air cleaner unit and Air Horn and S-belt need to be removed. Are you sure TC I defer to you since I have never done the alternator job before but I sure gave that area a good look a couple of weeks ago when I did the Water pump ;)


Can be done without a plenum pull. Goldcylon has the right idea.

[GOLDCYLON]

Can be done without a plenum pull. Goldcylon has the right idea.

:dancing

Greg batten down the hatches bro its looking bad!!!!!!! Tell Ike to go Away Tinas not home !!!

[tccrab]

Can be done without a plenum pull. Goldcylon has the right idea.

Thanks guys, good information.
Saves lots of time.
I wasn't sure if the plenum had to come off or not. It didn't look like there was enough room to wiggle it out from under there without lifting off the plenum. It's been a couple of years since I've been under the plenum (thank gosh).

TomC

[Sgreg]

:dancing

Greg batten down the hatches bro its looking bad!!!!!!! Tell Ike to go Away Tinas not home !!!

Yeah, I figure I will lose the power in the hacienda any minute now. Starting to blow pretty good. Adios !!

[tf95ZR1]

Whenever my SES light has gone on it was (just) the battery.
Removing the alternator is a lot of work however you get access to it.
Is there any way to test the alternator on the car? ie test it
under load?
I would do that first.
My $0.02
Good luck,
Ted

Oops, big FU. It was when my SYS light goes on, not SES. Sorry.
How do I know? My SYS just lit up, had to charge battery.

[Pete]

If your only getting 12.2 volts with it running sounds like the alternator.
Myrray's Auto Parts
Autolite #A145761 $112 + $18 core

Pete

[Shinto]

I put an oscilloscope on the alternator output while the car is running. There is a small noise component present, but it nearly didn't register. No DC and negligible AC signal.

Every place I've looked it seems to be special order (not a huge surprise, but still annoying). I called around the dealerships and one thinks he can have it today... Of course the price is considerably higher than a rebuilt ($250+tax and $18 core), but on the flip side, its new and I can have it today (maybe). BTW, the parts guy said that the part has been discontinued by GM, but there are about 14 left in the various zone warehouses.

Greg: That's the best news to come out of this whole episode. I really didn't want to get that far into the motor without replacing coils and injectors, but of course can't afford to do either right now.

Pete: That's the best price I've seen so far. Unfortunately, this is my daily driver and I need the part asap.

Tom: I'll give you a call as soon as I can procure the part. I may (or may not) have all the tools needed, but haven't dug this far into the engine before and don't have anything more than a generic Haynes manual. All my books on the ZR-1 and the LT-5 are in storage, so I don't even have a decent cutaway or exploded diagram. Your first hand knowledge could save me lots of time.

[IowaZR-1]

it can be done without a plenum pull......been there.......done that....can't remember for sure but you might have to pull the pulley off...if so make a special wrench to put it back on....weld a 16 inch long 1/2 bar to a socket on the side leaving the hole open thru it....an allen wrench will fit thru to hold the shaft as you tighten the nut

[Shinto]

Without pulling the plenum, will it come out from the side or the front? Trying to plan the route with a minimum amount of disassembly. I noticed the plenum dips downward just ahead of the alternator, but there are a couple of sensors, vacuum lines, and possibly the oil fill cap and filter in the way to the side. The coolant line is in the way in either direction. Gonna be fun...

[IowaZR-1]

Without pulling the plenum, will it come out from the side or the front? Trying to plan the route with a minimum amount of disassembly. I noticed the plenum dips downward just ahead of the alternator, but there are a couple of sensors, vacuum lines, and possibly the oil fill cap and filter in the way to the side. The coolant line is in the way in either direction. Gonna be fun...
I just looked at the service manual to refresh how it comes out...it comes out the front....remove negative battery cable...air horn and duct...alternator pulley and fan...and a couple of brackets(upper and lower)...the bolts are different lengths so label them or keep them straight some way...the rear brace...oil pressure sender(may need a special socket for this)... and the battery and regulator connections...good luck!

[Shinto]

Well, I got it apart, but took a slightly different route. Disconnect battery power, oil pressure sender (used a 1-1/16" open end wrench and it fit fine), the air temp sensor on the side of the air horn and whatever sensor that is on the side of the throttle body, the coolant tube alongside the motor, the belt, intake hose, air horn and then the throttle body. Slid right out with room to spare. No need to wrestle with the pulley and fan and make a special tool. The rear support could stay put too (especially since I couldn't get the bolt out of the hole past the front #2 cyl injector). Of course I'll be cutting new gaskets for the throttle body and coolant tube for the next hour or so but... I think I might just get this thing done tonight.

It's a far cry from changing the alternator on my '78 T/A -- that only takes about 3-4 minutes and 2 open end wrenches...

As a side note, did any of you notice there are small coolant passages in the top of the plenum and into the top of the throttle body? Obviously there for smog, but closing these off may net a couple of easy horses...