1987GT

Hi, I have a question that maybe someone could help me out with.I have a 1987 mustang5.0 gt andI just installed a Powermaster 140amp alternator and a yellow top optima battery, the reason being is I have a large stereo and the stock alternator just aren't cutting it. THe problem is my stereo isn't even hooked up yet and I am still getting very low battery power. When I start the car the battery gauge spikes real low and sometimes the car turns off. If I start it back up again usually it settles down after a couple of seconds and everything is fine. But then if I turn on say the headlights and heater the battery power gets real low, and I haven't even hooked up my stereo yet. Anyone have any suggestions? Both the alternator and battery are brand new, could it be a different problem?</P>


Any help is much appreciated.</P>


Thanks!!!!</P><edited><editID>1987GT</editID><editDate>38000.9080555556</editDate></edited>

hotrodman

do you have after market pulleys

BLKSTANG9879

Put a voltage meter in the ALT. and get a reading fo what it's putting out. And you also might want to invest in a after market volt gauge. Because the stock gauge isn't accurate at all. That is most likely your problem there.

1987GT

I don't have aftermarket pulleys.</P>


I'll do that with the alt, even if the gauge isn't accurate I can still tell that the power is low as it idles real low and the lights dim, also I have never had this problem before and the gauge was always correct with past alternators/batteries.</P>

jeep45238

Loose connection somewhere?

1987GT

I checked everything, is it possible that the battery isn't grounding properly? Also when you hook up the alternator you don't use the stock power cord cause they supply one to use instead, I disconnected the stock power cord from the alternator but not from the battery post, is it possible that power is draining through that cord, it's not connected to anything. I haven't removed it cause I don't know which wire it is exactly.

jeep45238

Loose connection somewhere down the line?

vfast

well do this, take it(alt) to auto zone and have it tested first..who knows it might be bad...then if it's ok..used the connection they gave you as it will hold the extra current coming from the alt.

BLKSTANG9879

Tell us how you made out.

makarovboy

I have the powermaster also, and mine "excites" (starts charging) at startup rpm. Your's may not. Try starting it and reving to about 2000rpm, as sometimes this is what it takes to make the alternator start charging. This is why powermaster gives you an alternative wiring setup in the instructions, as some alts don't excite without a little extra help. I don't have the instructions in front of me, but it involves the splicing of one or two wires in one of the stock plugs. I was prepared to do this, but it wasn't necessary in my case. Read back thru the directions, I think that will solve your problem.