Alternators--ZZZzzapp


). Anyway; I remember reading here on the forum that someone bought an alt., & paid something like $150.00 for it, & someone else said that that was cheap. I was checking prices in my are for rebuilts for my `87, & they ranged anywhere from $79.00-$135.00 w/exchange. Most had a 1yr warranty. I finally settled on getting one from National Auto stores, because it was only $89.00 w/exchange, but the best part is that it comes with a lifetime warranty. Just thought I`d pass it on. Ken
I don't know how it is by you, but I only go to the dealer for my alt. I got so many "Lifetime Warranty" alts. Yea it has a lifetime warranty, but that doesnt help when you're stranded.
They might as weel crap in a box and put a lifetime warranty, at least I know upfront what I'm getting.
Sorry sore spot with me
ok feel better


My
Ken
GM alternators are a frequent complaint on NHTSA hotline or complaint list (but unless the car rolls over, it's hard to get their attention). When Car & Driver was testing an early '97 C5, they got stranded in Georgia when the alternator crapped out and no replacements were available. The Vette's problems (well at least for the early C4's) seem to be well documented and even Gordon Killebrew mentions it in his Dash Repair manual. In the early '90's, Corvette Fever recommended that you carry a spare or upgrade it to a higher output model. 3 of the replacements on my Vette were under the factory warranty.
The problem seems to be the proximity of the exhaust header and an electrical system that can easily overwhelm the output of the alternator, especially with all of the accessories on at extended idle. From everything I've read, this creates extra heat and that eventually kills it. Compacted, FWD's seem to suffer the same fate, with the GM 6 banger putting the alternator on the firewall side. Note that Ford (and I believe Chrysler too), at least have it on the radiator side where it can get a better shot at cooler air.
I've always thought, that as a group, it would make a great class action suit. Even if the class was limited to maybe 100,000 C4 Vette owners, a $250 replacement cost should get the average civil atty drooling. In fact there was an attorney on the Forum and I suggested this to him after he experienced the same fate many of us have had with the Vette alternator - unfortunately, he only practiced criminal law and I haven't seen him since, so he may have given up and sold the Vette.
Charging System - Low Voltage Display ON/Dim Lights
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 02-06-03-008
Date: August, 2002
INFORMATION
Subject:
Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output
Models:
1990-2003 Passenger Cars and Light Duty Trucks
2003 HUMMER H2
This bulletin is being revised to update the model years and to update text. Please discard Corporate Bulletin Number 43-64-07A (Section 06 - Engine).
Any vehicle may have a low voltage display (if equipped with gauges), lights that dim at stop lights, slow cranking, no start, low generator output at idle or dim lights at idle when electrical loads are heavy at idle or under slow driving or infrequent usage conditions. These characteristics may be more noticeable with customer added electrical accessories, or with a discharged battery. These are normal operating characteristics of a vehicle electrical system and no repairs should be attempted unless a proven fault has been diagnosed.
During normal driving conditions, when engine speed is above 1000 RPM, the generator is designed to do two things:
^ Supply the current necessary to operate the vehicle's originally equipped electrical devices (loads).
^ Recharge/ maintain the battery's state of charge.
The following factors may affect generator and battery performance:
^ Non-usage of the vehicle for extended periods of time. The vehicle's computers, clocks and the like will cause the battery state of charge to drop (For example; 30 days in a parking lot and the vehicle may not start because of a dead battery or a vehicle which is driven to church only on Sunday may end up with a discharged battery to the point where the vehicle may not start). This would be considered abnormal usage of the vehicle and the normally expected result for the vehicle battery, generator and electrical systems.
^ At idle, vehicle electrical loads may exceed the low speed current (amperage) output of the generator and when this happens the shortfall comes from the battery. This will result in a drop in the electrical system voltage as the battery delivers the additional electrical current to meet the demand. This is equivalent to the brown outs experienced by homes and businesses when the electrical demand is more than the supply. See Figure 1.
^ Extended periods of engine idling, with high electrical loads, may result in a discharged battery. Attempting to recharge a battery by letting the engine run at idle may not be beneficial unless all electrical loads are turned "OFF".
^ Increased internal generator temperatures from extended idling can also contribute to lower electrical system voltage. As the generator's internal temperature rises, the generator's output capability is reduced due to increased electrical resistance.
Depending on the vehicle application, generator current (amperage) output at engine idle speeds of 600-700 RPM can be as low as 35 percent of the full rated output. With enough electrical loads "ON" it is easy to exceed the generator current (amperage) output when the engine is at an idle of 600-700 RPM. This is a normal condition. The battery supplements for short periods of time. Items that affect the vehicle's electrical system current and voltage at idle are the number of electrical loads being used, including add-on accessories, and extended idle times. When the vehicle speed is above approximately 24 km/h (15 mph), the engine/generator RPM is high enough and the generator current (amperage ) output is sufficient to supply the current (amperage) requirements of the vehicle as originally equipped and recharge the battery.
Dimming lights at idle may be considered normal for two reasons:
1. As the engine/generator speed changes, so will the current (amperage) output of the generator. As a vehicle slows, engine/generator RPM slows, and the current (amperage) output of the generator may not be sufficient to supply the loads, the vehicle system voltage will drop and the lights will dim. Dimming of the lights is an indication that current is being pulled from the battery. If the battery is in a low state-of-charge (discharged condition), the driver will notice a more pronounced dimming than a vehicle with a fully charged battery.
2. When high current loads (blower, rear defogger, headlamps, cooling fan, heated seats, power seats, electric "AIR" pump, or power windows) are operating or cycled "ON", the generator's voltage regulator can delay the rise in output. This effect, usually at lower engine speeds, can take up to ten seconds to ramp up the generator output. This is done to avoid loading the engine severely. To increase current (amperage) output, additional torque is consumed by the generator. The engine computer (PCM) will ramp up engine/generator speed in small steps so engine speed variations are not noticeable to the driver.
The Best of Corvette for Corvette Enthusiasts
There are a couple of options that I have seen on the Forum over the years, and that's a conversion to a CS144 or in some cases a CS145. The 144 is for a ZR1. Those things are run in the valley of the engine, so they are nowhere near any free flowing air. Apparently, the General made the circuit boards stout.
FYI, the old GM "1 wire" alts were very good and lasted a long time...they were a different animal.








