HT4100 4.1, 4.5, 4.9 Discussion, Alternator in Cadillac Engine Technical Discussion; In the middle of locating a bad ground somewhere in my Seville. Just replaced the Alternator and all symptoms prior ...
In the middle of locating a bad ground somewhere in my Seville. Just replaced the Alternator and all symptoms prior are gone EXCEPT the lights dimming for a moment when engaging the blower on high or medium. Stubborn as I am to be sure of things I held all four window switches up to see and it increased the load on the alt. Which logically drove the thing to working to compensate it. Question though being out of curiosity, and assuming I find the wire(s) I feel are at fault for some of this, what are my chances the alt I bought of rock auto is goofed already?. Seems unlikely and more likely I have something messing up the system. Just curious for feedback I guess. Thanks.
First thing to keep in mind is that alternator ratings are for higher RPMs (typically over 3k RPMs) and are much much weaker at idle RPMs. Also, once you exceed the amps that the alternator will generate, you have to go to the battery for additional current, and different batteries will release the energy at different rates as well (the "cold crank amps" or CCA is a good thumb measure). Finally, your blower motor pulls a lot of amps, and at startup it is overcoming a lot of resistance, so if you are seeing draw problems at idle then most likely is the battery is bottleneck.
By way of example, I used to have really slow windows, even replaced the motors and they were still slow, put in a new alternator still slow, then put a high-CCA Optima Red Top in and the window motor speed doubled.
Batteries seem simple enough.......they start the engine, act as a ballast or accumulator for electrical power etc, but sometimes.......they are barely keeping up the voltage and current capacity demands of the system, and don't just roll over and die like usual. Like ehall says, it sure could be a battery problem. Getting a new (good) one in there would eliminate that part from being suspect.
Planning on a tune up at the shop and adding a new battery when i order brake pads and rotors up. Will see how it goes. Its a 25 year old Caddy and I have OCD so I am slowly just being happy I have her running besides the nuisance of starting and light dim issues. Still looks gorgeous so that counts
So I think I have finally pinned the problem as to my slow starts that faded away lately and the light flicker. The lights ALWAYS do the dim and return to normal thing. HOwever after obsessive thinking I realized the reason for the slow return to normal start ups. After I installed the new alt I drove the car only once for an extended period of time, 250 mile trip each way. It started fine there, while at the lake, and when I got home. After a few weeks was when the random slow starts happened. During this time I was only going to class(10 minute drive) and work (4-5 minute drive). This was also during the middle of the winter to spring transition so I would crank the blower and have heat on though mild. As well my classes being at night I would have the lights on for half my drives roughly. As well my drives all allow me nearly half the time spent driving, to be coasting down the road thus never reaching higher RPMs.The importance of all this being that I afterwards realized during our warm up here that the starts returned to the normal time once the car had the chance to recharge finally. My short bursts of use coupled with using almost ALL the high powered electronics in the car never allowed the system to get back to normal. So currently, its running fine and no concerns. Lesson to myself to not let OCD take over and jump over all possibilities so fast.
Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
That car had a tendency for the smog pump belt to loosen which in turn causes the alternator belt to slip. To verify, try rotating the alt. pulley by hand against normal rotation. If it moves at all, the smog pump belt is too loose or worn out. A slipping smog belt will cause lower than normal charge output from the alternator. The alternator belt only wraps around the upper water pump pulley on that engine and the smog pump belt wraps around the crankshaft pulley and the water pump.
I replaced the alt and the battery before taking it in the shop for calipers etc.
I think you may be right on with the belt. i am gonna grab the back up I have in the garage and see if the pump sound I get is what is throwing the twinkling light issue I am having. I made a new post on that issue too.