frankrizz

hey members, I had a bad miss at high rpm between 2nd and 3rd gear.
Tranny checked out ok at a reputable shop. Tech noticed a voltage drop from 13.6 volts to 11.6 with all accessories on including a/c. The miss sounds like a stumble, then smoothes out when I let off the gas. Code 50 came up on scan. Any thoughts?

Chimera96

code 50 would be system voltage low

at 11.6 vdc sounds like the voltage regulator inside the alternator (assuming you are using the donor car alt) is bad. You can buy parts and replace or just get a new alt

low voltage will make computer controlled cars have all kinds of issues...like miss/stumble

Typically high RPM stumble/misfire is a failing Optispark

given your low output voltage....you need to correct that and ideally the stumble will go away

Alt should be putting out about 14.6 vdc to the battery.

RobbyRob

I had the same problem and I rebuilt my alternator to a 200 amp and did a direct power to the fuel pump and up graded battery cables. Reduced the voltage drops big time.

plattted

What steps did you take to upgrade the Alt to 200 amps?

Thanks

Chimera96

Having a quality set of battery cables helps reduce/eliminate voltage drop. I got cables from this place. Gary makes great stuff

Camaro | Innovative Wiring LLC

200 amp kits to rebuild the alt are available online if you feel you need it. IMHO those are for the big stereo amp guys. I just replaced brushes in mine. There are "how to " videos online so rebuilding the alt is not hard.

Injuneer

Agreed - stock engines, and even heavily modified engines (I run two fuel pumps, huge low impedance injectors, two ECU's, bottle heaters, heavy instrumentation, etc.) seem to have no problem surviving with the stock 140-amp alternator.