EFI AMP question

[stangman16]

How many amps does the EFI engine (stock) require to run properly. I haven't upgraded my alternator yet, due to funds, and I'm curious if I can even drive it around for a test run with this low amp alt. I'm not exactly sure of the amps but it's a GM alt put on by the previous owner. I had to buy a new one long ago, and I can't remember what vehicle it matched to. Back then this was my daily driver and I had to use the GM replacement since I didn't have time to hunt down a harness for the '66 Mustang alt.


Just finishing up the EFI wiring and hiding some of the engine compartment wiring after repainting the engine bay.

What do you think? (ignore the red arrows)

granted I'm still young and low on experience with car restoration, but I think it turned out pretty good for my first time. This car will never be a show car, especially after looking at all front end sheet metal - it all needs to be replace, frame rails including.

Thanks for replying!

-Jeremy

 

[ForceFed70]

Well, this is a bit of a loaded question as it's hard to determine where the EFI system stops and other components take over.

For example: An electric fuel pump is required for EFI. Do you consider the pump as part of the system?

To power the ECU, fuel injectors, standard TFI ignition system, and electric fuel pump you should budget approx 25amps depending on the fuel pump used. If you plan to use a bigger pump than stock, closer to 30A.

 

[Hack]

Late 80s Mustangs came with 65 amp alternators, but the headlights dim and the fan slows sitting at a stop light if you are trying to run defrost on a cold night. The ECU doesn't malfunction under those conditions, so running a weaker alternator won't kill the motor. However...

I put a 3G alternator in my '70 with a carbed engine and no aftermarket electrical items and the car works MUCH better. The headlights and dash lights are much brighter.

When I converted my '83 Mustang to EFI I put in a 130 amp 3G (bought at the junkyard for $25) in there with the wiring kit from PA Performance. It was well worth it IMO. I run everything at once and never worry about the battery discharging.

I would highly recommend taking the time to put a strong alternator in your car. It will last longer than a weaker one and all your electrical accessories will WORK. However, I'd be surprised if you have any problems with the GM alternator. Most all cars come with at least 65 amp alternators from what I've seen.

 

[stangman16]

Right on, thanks for the help. I have a holley high flow fuel pump (external) so I'll plan on the 30amps... No big stereo, just 12x9's in rear and Pioneer deck.



http://cgi.ebay.com/ebaymotors/FORD...ryZ33573QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

is this a good one?

Would increasing the amp's create a greater possibility of an electrical fire? I have an electric regulator, but I just want to be sure I don't cause I fire since I won't have funds (or time) to upgrade the wiring until next winter...