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Discussion Starter #1
I am new to using the built in diagnostic mode on my '85 deville, but it shot out a E16 which i found in a sticky to mean generator volatge out of range. now for starters I know that I dont have a generator its an alternator. But I do get pulsing lights ie; headlights, map lights, dash lights, ect. I have been having this problem for a while now and it is very annoying to say the least. But does this mean that the alternator is bad and needs to be replaced? My service engine soon has been coming on and off recently but it doesnt stay on for long maybe 30 sec at the most. So does anyone have any tips they can share?
 

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81 Coupe DeVille 4/6/8
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Sounds like the voltage regulator to me, which is built in on GM alterntors I believe. So probley, but I would listen to some of these more experianced guys.
 

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13 Challenger RT, 11 CTS Coupe Premium, 94 Eldorado (RIP)
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Voltage regulator like LaneWvr said. I had one that would crap out on me all the time in my 72 Olds. That one was external. I think yours is internal.
 

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94 Fleetwood Brougham
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73 or 74 was the switch to the 10SI (system integrated, regulator built in) alternator, up to 63 amps. In the 80's, the 12SI came out with more power, up to 90-95 amps. The are direct interchange and a great low buck upgrade. ID 12SI's with fiberglass fans. 90 Jeep Grand Wagoneer's had highest amperages and fit most any GM car with 10 or 12SI.

There is a 15 SI, which is a larger case and came in a 70 amp model. This was the basis for the newer design CS144 140amp alternator that is on many 80's and 90's Cadillacs. It can be adapted with some work, not a true bolt on like the 10SI to 12SI, with is 100% interchangeable.

There was an oddball 80amp "large frame" alternator, commonly found on diesels and cop cars in the 70's and early 80's. This one need special bracketry to be used, and not a recommended swap. Oddball 24v models for the Military are out there too.
 

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Discussion Starter #5
OK so I went to Advanced auto, the guy helped me out and we both came to the conclusion that I had a 120 amp alt. ordered it and it had completly differnt mounting brackets and had a v-belt pully, took it back and determined it was a 108 amp model. I was kinda bumbed because of the lower amerage, but you are saying that the 12SI would be a direct bolt on meaning the same houseing and mounting brackets? and the jeep grand wagoneer had the highest amperage? I ask because I do run an amp pushing 450watts RMS and some accent neon lights, I just want to make sure the alternator is gonna be able to handle the load. If you could clear this up for me ASAP since i already ordered the 108 amp alt from advanced and was kinda hoping to put it in today. thanks
 

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94 Fleetwood Brougham
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http://www.extreme4wheelin.com/tech/alternators/tech.htm

Which one do you have?

Tom

Bigger is always better in my book, although I have had 1 Autozone parts counter guy try to tell me I was wrong and bigger alternator wouldn't help me. Yeah, right. (96 Suburban, 4x4, dual AC, yeah, I need bigger!)

You have the HT4100 engine, right? FWD? If so, you can likely adapt the 4.9L CS144 (140amp) brackets if you don't have them already.

http://www.4alterstart.com/alternators/ lists a CS144 @ 200amp (aftermarket reg likely, not factory).

The Wagoneer had a 12SI, like 94amp. My 85 Cutlass had a 85 amp 12SI. I just swapped it with a Jeep one (as Jeep used GM parts often) and got the bigger one.

jbrunell said:
OK so I went to Advanced auto, the guy helped me out and we both came to the conclusion that I had a 120 amp alt. ordered it and it had completly differnt mounting brackets and had a v-belt pully, took it back and determined it was a 108 amp model. I was kinda bumbed because of the lower amerage, but you are saying that the 12SI would be a direct bolt on meaning the same houseing and mounting brackets? and the jeep grand wagoneer had the highest amperage? I ask because I do run an amp pushing 450watts RMS and some accent neon lights, I just want to make sure the alternator is gonna be able to handle the load. If you could clear this up for me ASAP since i already ordered the 108 amp alt from advanced and was kinda hoping to put it in today. thanks
 

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Discussion Starter #7
Well I checked with the dealer today to be sure of which alternator I was suppose to have. They told me that it was the 108 amp which is the one that came in today at advance auto. So after installing it I could imediatly tell the difference, no pulsing lights at all, even with my amp on and the subs hitting hard the headlights didnt dim at all. I guess ill stick with this one since it seems to hold up to the load at this point. Im not trying to win any sound system contests so Im not drawing tons and tons of power. Thanks for all the help guys I really appreciate it.
 

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81 Coupe DeVille 4/6/8
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I wish I would've checked back here earlier. I don't recommend Advanced Auto for alternators. Out of the last 5 I've had 3 bad ones. 2 in the Miata, still the charge light comes on, bad connection in the alternator. Then after that experiance for some reason I got one there for my 92 Cutless. First one had the same problem, the second has okay. So if you have issues with it, have them give you the money back and go to Carquest or Napa. Good luck with it.
 

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13 Challenger RT, 11 CTS Coupe Premium, 94 Eldorado (RIP)
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Back when Advance Auto was called Discount Auto, I use to get alternators for my 72 Olds there. I say alternators (plural) because they would screw the pooch almost once every 1.5 years. They had lifetime warranties on them, fortunately. Any they were a cinch to install on the big 455.
 

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Discussion Starter #10
Ok so this new alternator that I got from Advance is "burning" i can smell it in the car and it is extremely hot to the touch. What is the deal im pretty sure my old alternator never got that hot i thought that was the purpose of the cooling fan, to keep the alternator from burning. Could it be a bad connection? I am 100% sure i hooked all the wired back up to where they were. Or is this just some break in smell and the alternator is just going to be that hot?
 

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If the burning smell is coming from the alternator, I would take it back to the store and get a replacement. It should be under warranty and they shouldn't give you any problem. You certainly shouldn't be smelling it when you are in the car. Verify the smell is coming from the alternator and not and wiring.
 
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