93 mustang lx running rough under electrical load

[Mjee42]

Hi everyone, I’m new here with a 93 5.0 notch, I’m having some running issues with the car. It runs great when there is minimal electrical load, as soon as I turn on lights, a/c... etc it starts to run really rough and miss a lot, also tach will start to jump around. I recently checked all my grounds and cleaned them hoping that would be the issue. I noticed I’m having awful voltage spikes when checking voltage at the battery. Wondering if a bad voltage regulator or alternator has made any of your cars run rough.

 

[broncojunkie]

Hi everyone, I’m new here with a 93 5.0 notch, I’m having some running issues with the car. It runs great when there is minimal electrical load, as soon as I turn on lights, a/c... etc it starts to run really rough and miss a lot, also tach will start to jump around. I recently checked all my grounds and cleaned them hoping that would be the issue. I noticed I’m having awful voltage spikes when checking voltage at the battery. Wondering if a bad voltage regulator or alternator has made any of your cars run rough.

Absolutely. A bad alternator or battery can cause all kinds of problems. Do you still have the factory alternator or has it been upgraded? Also, do you have any aftermarket electrical accessories like electric fan, stereo amps, fuel pump, etc? The factory alternator in these cars are barely enough for the stock setup, so any added electrical accessories can cause major problems. Factor in a tired alternator and battery and eroding cables and you're guaranteed to have issues.

I suggest a 3g upgrade. Fairly easy job and parts can be had cheap, if you plan in advance (assuming yours hasn't been upgraded already, of course).

You can also take your alternator off and the parts stores can put it on a machine to bench test it. That will tell you what kind of amps it's putting out.

 

[Mjee42]

Absolutely. A bad alternator or battery can cause all kinds of problems. Do you still have the factory alternator or has it been upgraded? Also, do you have any aftermarket electrical accessories like electric fan, stereo amps, fuel pump, etc? The factory alternator in these cars are barely enough for the stock setup, so any added electrical accessories can cause major problems. Factor in a tired alternator and battery and eroding cables and you're guaranteed to have issues.

I suggest a 3g upgrade. Fairly easy job and parts can be had cheap, if you plan in advance (assuming yours hasn't been upgraded already, of course).

You can also take your alternator off and the parts stores can put it on a machine to bench test it. That will tell you what kind of amps it's putting out.

Thank you for the response, I do have some accessories like electric fans etc... but I also do have the 3g alternator upgrade before I purchased the car. I do see some cracks on the body of the alternator, which is the reason for questioning it’s reliability. But I’m glad to hear that a faulty one can make a fox run rough. I’ve already got a new 130 amp alternator in, so I’ll get it on the next couple days and keep you posted. My battery is an older optima, but I haven’t had problems with it. And it looks like the wiring to the alternator has been upgraded, but I’ll definitely check all my wires for corrosion and wear. Thnx again