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I installed a Mechman 250 amp alternator a few weeks ago and I went to the track today to do some bracket racing. Everything was well after my two practice runs, but when I started my car up in the staging lanes I noticed that my gauge was in the red. I ended up winning the race, but I went home after that round in fear of me being left high and dry at the track!
When I got home my battery was reading 11.25 with the car running and 10.75 after I turned off the car. I am thinking that the nut that goes on the back of the alternator, the one that connects to the battery, is loose. At least that is what I am hoping. Does anyone have any alternate theories? The battery should be reading around 14 volts when the car is running and around 12 with the car not running.
that's great advice...no, I haven't checked the nut yet, i'm going to wait till morning when it's not so bloody hot and the engine has cooled down. When I posted this my engine was still hot...
So I talked to Mechman Alternators and they said that since I didn't run a 2 gauge cable from ground back to the alternator I probably fried the diodes in the rectifier. The only thing is, I didn't have a lug for the return ground. They are going to fix/replace it for free so I am happy. I requested that they send me one back with a ground lug.
So I talked to Mechman Alternators and they said that since I didn't run a 2 gauge cable from ground back to the alternator I probably fried the diodes in the rectifier. The only thing is, I didn't have a lug for the return ground. They are going to fix/replace it for free so I am happy. I requested that they send me one back with a ground lug.
Yeah that may have done it, big alternator trying to pump out amps and no where for it to go..
I think I went overkill and I have 4 different ground cables added to the corners of the block and on the alternator bracket. I was tracing random misfires and I had relays melting, long story "short" the engine harness had a fray at the alternator excitor wire and the primary oxygen sensor wiring also had a fray and they were just rubbing themselves into arcing
I did 2 gauge wiring for power, and for the fuse supply, and primary ground from the battery to block and chassis. I used the factory ground cable to bolt to the atlernator bracket case and bolted that to the frame rail under the fuse box
I have the 105 amp alternator off of my truck on the Camaro, and a new duralast gold on my truck. The f-body hates the aftermarket voltage regulators or something. I've verified several times that only a GM alternator will cure my check gauges light dimly lit at night. Has to be an OG unit
Last edited by chrysler kid; Aug 1, 2018 at 12:50 PM.
I think I went overkill and I have 4 different ground cables added to the corners of the block and on the alternator bracket. I was tracing random misfires and I had relays melting, long story "short" the engine harness had a fray at the alternator excitor wire and the primary oxygen sensor wiring also had a fray and they were just rubbing themselves into arcing
I did 2 gauge wiring for power, and for the fuse supply, and primary ground from the battery to block and chassis. I used the factory ground cable to bolt to the atlernator bracket case and bolted that to the frame rail under the fuse box
I have the 105 amp alternator off of my truck on the Camaro, and a new duralast gold on my truck. The f-body hates the aftermarket voltage regulators or something. I've verified several times that only a GM alternator will cure my check gauges light dimly lit at night. Has to be an OG unit
Yeah you went way overkill lol.
And I agree about the OE alternator thing, that's why I made that alternator thread about using used truck alternators. They were the only ones that acted right. A new dealership or ac delco unit may act right, but when you can get one for $60 vs $300-$400, I'll take the $60 one.
I think I went overkill and I have 4 different ground cables added to the corners of the block and on the alternator bracket. I was tracing random misfires and I had relays melting, long story "short" the engine harness had a fray at the alternator excitor wire and the primary oxygen sensor wiring also had a fray and they were just rubbing themselves into arcing
I did 2 gauge wiring for power, and for the fuse supply, and primary ground from the battery to block and chassis. I used the factory ground cable to bolt to the atlernator bracket case and bolted that to the frame rail under the fuse box
I have the 105 amp alternator off of my truck on the Camaro, and a new duralast gold on my truck. The f-body hates the aftermarket voltage regulators or something. I've verified several times that only a GM alternator will cure my check gauges light dimly lit at night. Has to be an OG unit
Can you elaborate more on your CEL being lightly lit. I have the same issue, and it’s driving me crazy.
Mechman Alternators makes a pigtail that you have to connect to a 12 volt keyed source that will make the check gauges light go away. Their phone number is 1-888-mechman.
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Help!!! Alternator not charging the battery!!!! 
