Experiencing electrical failure - Page 2 - ZR-1 Net Registry Forums

Shinto · 09-13-2008

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 · 09-14-2008

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 · 09-14-2008

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 · 09-14-2008

Quote:

Originally Posted by 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...

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 · 09-15-2008

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...

09-13-2008	#11
Shinto Join Date: Oct 2007 Location: Sacramento, CA Posts: 16	Re: Experiencing electrical failure 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. __________________ 1991 ZR-1 #1926 Black/Black, Borla Exhaust w/ X-pipe

09-14-2008	#12
IowaZR-1 Join Date: Feb 2006 Location: Iowa aka "one big cornfield" Posts: 341	Re: Experiencing electrical failure 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 Last edited by IowaZR-1; 09-14-2008 at 11:29 AM.

09-14-2008	#13
Shinto Join Date: Oct 2007 Location: Sacramento, CA Posts: 16	Re: Experiencing electrical failure 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... __________________ 1991 ZR-1 #1926 Black/Black, Borla Exhaust w/ X-pipe

09-15-2008	#15
Shinto Join Date: Oct 2007 Location: Sacramento, CA Posts: 16	Re: Experiencing electrical failure 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... __________________ 1991 ZR-1 #1926 Black/Black, Borla Exhaust w/ X-pipe