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New alternator doesn't charge

7K views 11 replies 6 participants last post by  Hot4.1 
#1 ·
I have put 4 remanufactured alternators from 2 vendors on my 1982 4.1 Deville hearse. All show less voltage than the battery when spinning. The alternators were tested good before installing.

The circuits to the alternator test good - battery voltage at the charge wire, at the circuit through the dash indicator light, and the direct battery circuit. The NO CHARGE indicator light comes on only at starting ignition sequence.

I can disconnect the battery and the engine continues to run.

What can be causing the voltage to drop and not charge the battery?

Any ideas?

I have never had a problem like this in my life.

Thank you.
 
#2 ·
The smog pump belt is too loose or worn out. Notice that the alt. belt only wraps around the waterpump. If the smog pump belt slips then that causes the water pump pulley to slip then that causes low charge rate from the alternator. If you can rotate the alt. pulley by hand against its normal rotation, ( ENGINE OFF) the smog pump belt is either too loose or glazed. It must be tightened from under the car. Watch the alt. belt as you rotate the alt. pulley. It will probably rotate the water pump pulley. If the smog pump belt is tight you will not be able to rotate the alt. by hand! If in fact, its slipping, the smog belt is history. It has been slipping long enough to be glazed and will never grip tightly. Virtually all the 4100 Cads I've owned had this issue.
 
#3 ·
That may explain the other problem(s).

That may explain the other problem(s).

She started overheating at the same time as the dead batteries.

By hand, the alt belt turns the fan easily in either direction. Is that normal? I was thinking the fan clutch may be defective. I prefer flex fans in Florida. Say that real fast 3 times. I also have a disdain for thermostats. It has been 95 degrees for weeks.

What did you mean by "normal rotation"? I understand ENGINE OFF, but not much else.

If you can rotate the alt. pulley by hand against its normal rotation, ( ENGINE OFF)
I am having a lot of difficulty locating and identifying the parts because it is a commercial chassis hearse and many things are different from the sedan. Does anyone have schematics of the engine compartment? I have been trying to find the IACV for a year. HT4100 TBI. Not sure where the EGR is either. I am sure they will need cleaning having driven all over the eastern half of the country. That revived my 95 Jag and 95 Buick. The hearse only has 60k miles.

I will have to go under the car to tighten the smog pump? belt. The A/C belt is loose, too, and looks burned and shrunk. I think I will take it to the mechanic for this. All the belts will have to come off to replace A/C belt. He was suggesting "module" but couldn't remember the full name - not ECM and not ignition module, something else.

Thanks for the excellent tip. I will let you know if belts help.

:thankyou:
 
#4 ·
Hot4.1 said:
That may explain the other problem(s).

She started overheating at the same time as the dead batteries.

By hand, the alt belt turns the fan easily in either direction. Is that normal? I was thinking the fan clutch may be defective. I prefer flex fans in Florida. Say that real fast 3 times. I also have a disdain for thermostats. It has been 95 degrees for weeks.

What did you mean by "normal rotation"? I understand ENGINE OFF, but not much else.

I am having a lot of difficulty locating and identifying the parts because it is a commercial chassis hearse and many things are different from the sedan. Does anyone have schematics of the engine compartment? I have been trying to find the IACV for a year. HT4100 TBI. Not sure where the EGR is either. I am sure they will need cleaning having driven all over the eastern half of the country. That revived my 95 Jag and 95 Buick. The hearse only has 60k miles.

I will have to go under the car to tighten the smog pump? belt. The A/C belt is loose, too, and looks burned and shrunk. I think I will take it to the mechanic for this. All the belts will have to come off to replace A/C belt. He was suggesting "module" but couldn't remember the full name - not ECM and not ignition module, something else.

Thanks for the excellent tip. I will let you know if belts help.

:thankyou:
He means if you can rotate the pulley the opposite way of how it usually spins.

And a 4100 in a hearse! Yikes! What was the coachbuilder thinking?
 
#5 · (Edited)
This car if an HT4100, does NOT have an IACV ( idle air control valve). It has an Idle control valve ( ICV!!! ) Please re read my post. You say the Fan turns easily either direction, is this normal? Hell no!! Watch the water pump pulley while you turn the alternator. You will see the smog pump belt slipping on the water pump pulley! The EGR valve is, like most V/8's, located on the passenger side of the intake manifold just behind the throttle body. I doubt anything under the hood would be different just because its a commercial chassis. And yes, have a mechanic replace the belts. Much easier on a rack with air tools and experience! And then you will have a warranty on the repair as well. HT 4100 in a hearse!!! some would say the rear passenger died just before this engine will :)
 
#6 ·
Re: That may explain the other problem(s).

I think you should take it to a good old school mechanic with a lift and all the bells and whistles. That pulley is a pain in the neck to do on the ground . Aside from that My advice is get a new AC delco 100 Amp alternator and at the same time A new battery , best investment . and have all the wires feeding the starter and the battery from alternator Replace bran new Corroded wires are terrible for performance . Have the mechanic put a bran new distributor and rotor and cap HEI they sell them as a kit now not expensive for this year . change to high performance ignition wires and AC delco plugs . So for about 650 bucks you should be ready to take a worry free ride , good luck also have the mechanic look at your catalytic converter Odds are its in bad shape see what he says to do .
 
#7 ·
Smog pump belt it was!!! The mechanic didn't believe it, but now he is a believer. Alternator charging, fan blowing, A/C cooling, life is good.

Don't badmouth my HT4100 hearse. She gets 25 mpg on the interstate (70 down the mountains). Running rough yet, but going to clean up the EGR and ACV if I can find them.

:worship: Thank you Carnut. I spent 2 weeks on the internet trying to figure this one out.
 
#12 ·
Exactly! I bought it in 2006 with 46,000 easy miles. I drive that way, anyway. I have owned several Cadillacs - 1959 lawn dart, 1964, 1966, 1982 sedan and 1982 hearse. Drove them all with respect. Got all my tools in the hearse, 24/7 road service for the kids. No racing with that floor jack in the back. I switch on the side markers and everybody pulls over to let me go on by.
:wave:
 
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