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71fastback

Well-known member
Joined
Sep 21, 2010
Messages
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Location
Littleton, CO.
My Car
1971 Mustang Sportsroof.
Hello to all,

I've got a stupid question. What happens when the alternator craps the bed? I mean, what would the symptoms be if were going bad or just not working at all?

Recently, I got underneath the Mustang and scraped as much of the 40 years worth of dirt and crust off the frame and block and anything else I could reach. After that, I took the air cleaner off. Covered the carb with tin foil, a plastic bag and put a big rubber band around it. I proceeded to spray Engine Brite all around underneath and around the top and sides of the engine. Scrubbed some really bad spots underneath. I waited the recommended 10-15 minutes and then sprayed the whole thing down with the hose. I waited a while and then started it up no problem and let it idle to dry out the engine.

I've driven it around for the last couple of days and started to notice it running a little rough but not too bad. Today, I drove it around running errands and after I came out of Costco and tried to start it up, it wouldn't idle and died. Luckily, I got it going again and made it home but it died in the driveway. But now, It doesn't want to idle and just dies. Sometimes, I can get it to idle and if I rev it up a little, it will die again.

I tried adjusting the carb but it still dies after reving it up a little.

Any help would be appreciated.

302, Edelbrock four barrel carb, Performer intake manifold, HEI distributor.

 
ok easy way to tell is alt is dead

step1 start car

2 disconect the negative side of battery

3 if dies alt is shot (works for checkin any alt)

4 if runs you have other problems

ok if it still runs after this.

id reccomend checking plugs then wires for contunity,

and run some sea foam through that thing

 
With the new alternators today, your farther ahead to take it somewhere and have it tested. The diode tree voltage regulators built in to really don't like the removing of the negative unless your still running a voltage regulator seperate of the alternator. Typically if the alternator is bad you'll kill your battery since this is the only power source available while driving. That's why you'll see those cars with the really dim lights at night.

If you take the cap off odds are you'll see moisture on it. Wipe it dry then pray some PB Blaster around your cap and wires at both ends and let sit awhile it will dry everthing out. Good luck!

 
Last edited by a moderator:
+1 on Markmels post. You can use silicone based spray also. The water got inside the cap and evaporates and condenses with each heat and cool cycle. Chuck

 
+3. I've got $5 that says you've got condensation under your distributor cap. Remove it and dry everything off and let it sit 15 minutes then put it back on and I bet she drives like she used to. Let us know.

 
If you have a voltmeter, check the battery voltage with the engine off and on. With the engine off you should get 12.6v or so and with the engine on you should see 13v-14v. When I check the alternator I turn on everything electrical to put high load on it.

 
Last edited by a moderator:
If you have dummy lights get aftermarket gauges they will help in the long run. As I posted in an other post once the dummy lights go on it's to late. When my girlfriends alternator died on the road she first lost here wipers then the engine died. we had to get it towed . when the alternator dies the car is running on battery power so it might die . After a rest it might start up again but not for long. +4 or 5 on getting your alternator tested.

 
ok easy way to tell is alt is dead

step1 start car

2 disconect the negative side of battery

3 if dies alt is shot (works for checkin any alt)

4 if runs you have other problems

ok if it still runs after this.

id reccomend checking plugs then wires for contunity,

and run some sea foam through that thing
What is sea foam?

 
i love that stuff, it will clean all the carbon out of the headsput it in your power break booster hose, or put it in ur tank and it will help keep your carb clean, my 2k f150 stated acting up put sea foam in the intake system no problems any more

 
ok easy way to tell is alt is dead

step1 start car

2 disconect the negative side of battery

3 if dies alt is shot (works for checkin any alt)

4 if runs you have other problems

ok if it still runs after this.

id reccomend checking plugs then wires for contunity,

and run some sea foam through that thing
What is sea foam?
http://www.seafoamsales.com/

 
I agree with the possible damp ingnition system. You might also check for a vacum leak. With all of the cleaning you could have removed dirt from a cracked / dried out vacum line or knocked one off while moving thinga around.

 
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