I have a 98 gmc jimmy with 117,000 miles on it and for the last week or so ive noticed that when i accelerate rappidly all of a sudden my headlights dim, battery gauge drops, dash lights fade, and the second my automatic trans. shifts all returns to normal.... I have a brand new battery in her and have been told by an autozone tech that my alternator is good and so forth... Please o please help!! Thanks in advance!!
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98 GMC Jimmy issue...
- Thread starter db98jimmy
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No replies yet.... what the...
Well i was hoping for more insight... Any ideas on what this might be?? All i do is accelerate and all of a sudden around 2000-2500rpm's my headlights and dash lights dim.... and the moment when my automatic trans shifts all power is restored... Please tell me im not the only one who this has happened to and seriously any help at all would me much appreciated
Well i was hoping for more insight... Any ideas on what this might be?? All i do is accelerate and all of a sudden around 2000-2500rpm's my headlights and dash lights dim.... and the moment when my automatic trans shifts all power is restored... Please tell me im not the only one who this has happened to and seriously any help at all would me much appreciated
mikefletcher85
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Im no mechanic, but I would have the alternator tested.
When they checked the alternator did they just check output at a set speed or did they vary the speed (like you do when you rev the engine)? It may be that the alternator is okay, but the regulator is bad. I don't know if you have an internal or external regulator, but it might not be a bad idea to replace the alternator anyway. It's not too hard and if it doesn't solve the problem you can just return the new one (check to be sure before you buy).
Also, how is your belt and belt tensioner? If the belt is slipping at high rpms that could also cause the problem.
Have you tried it with the A/C on and off? You may be able to change the effect by changing load on the engine which would help diagnose the problem.
Also, how is your belt and belt tensioner? If the belt is slipping at high rpms that could also cause the problem.
Have you tried it with the A/C on and off? You may be able to change the effect by changing load on the engine which would help diagnose the problem.
The other thing to check is the ground to your fuel pump. As you accelerate the pump is asking for more current to give you more fuel pressure, and if you have a poor ground connection then it will want even more current. This may end up being more than the CS144 alternator can produce.
Notice that I said current and not voltage. A poor ground will increase the resistance in the circuit which is what causes the current to rise, as the pump motor is wanting a set number of watts. Remember that watts is volts times amps (cuurent).
You also could look at upgrading your alt to an AD244
Notice that I said current and not voltage. A poor ground will increase the resistance in the circuit which is what causes the current to rise, as the pump motor is wanting a set number of watts. Remember that watts is volts times amps (cuurent).
You also could look at upgrading your alt to an AD244