Mercury '91 Capri alternator continually fails
Asked by Ronaldstein Apr 08, 2020 at 01:40 PM about the 1991 Mercury Capri Convertible FWD
Question type: Maintenance & Repair
So I bought a Capri back in November as a project car, and have fixed
everything (distributor, brakes, multiple sensors, battery replacement ect.),
but then the alternator failed, so I purchased a re-manufactured alternator
because I couldn't find a new one anywhere. It lasted about a month before
slowly producing less and less voltage, so i replaced it because it had a
warranty. This has continued for a few months, a couple times The
alternator barely lasted a few hours. Has anyone else had this issue and
knows a solution? I am at my whits end of this, and no, it is not a cheap re-
manufacture like some out there that are basically guaranteed to last 4
minutes and 23 seconds max. Thanks! also, i was led to believe it is the
voltage regulator causing the issue but i'm not 100% sure
11 Answers
Ronaldstein answered 4 years ago
belt tension is okay and belt is in good shape, also checked wiring and it seems to be just fine. Would a bad battery cause a regulator to fail?
I had a similar problem. Check the resistance of the cable from the "B" plus on the alternator to the positive battery terminal . Mine look good but had high resistance . I added a number 10 wire to the same connections and that did it . Also , there can be many other reasons while you are having this problem .
Ronaldstein answered 4 years ago
I’ll try that, which is the B plus wire? The main positive lead going to the battery?
yes , it is always hot . so i ran mine inside cable sleeve [I think that is what they call it , its cheap ] It was 9 years ago and it worked for me . I had 3 Capris [2 brand new ] . at one time and they are fun but always need work . The 92 turbo has 221K miles and still has power . A lot of people ask me about it when it is parked . Good Luck !
Ronaldstein answered 4 years ago
okay, just replaced b plus wire, it was a bit corroded. Also just put in a new battery, and got a new alternator. Replaced Battery terminal connectors because they were in bad shape. alternator didn't last more than a day.
Ronaldstein answered 4 years ago
It also never produced 14 volts like it should, was just over 13. I am at my wits end here. Anyone experianced this?
I have all the manuals and electrical manuals for the Capri but cant find anything that relates to your problem . the 91 has the Bosch alternator . 92 went to Mitsubishi alternator . check the "S'" terminal on Alternator for batt voltage . Install an amp gauge between B plus wire and batt to see output . otherwise you are missing something in your trouble shooting . How are you changing the alternator . ?? Out the top or bottom ??
To RONALDSTEIN How are you doing with your alternator problem ??
Ronaldstein answered 4 years ago
hello! So there are no shorts, and because the alternator never produced voltage I'm thinking it was faulty to begin with. Instead I am looking for an old capri from a pick and pull to grab the alternator from, I can't find another alternator that's in my budget.
Ronaldstein answered 4 years ago
Alternator is being changed out the top, rather difficult in a capri with A/C
Advance Auto - Auto zone - etc. will test your Alternator for free . that way you will know if is any good .
