here's the situation:

ALT light on the dashboard flashes on an off sporadically, especially when decelerating and idling, but goes away upon acceleration or cruising. Engine randomly misfires, not too badly, but steady enough **** me off. There is a whining noise that comes from fuel pump area, but sometimes it sounds like it's coming from the distributor. Somehow I think all these things are related, but the noise never stops, and I can't understand how a whining noise would set off the ALT light.

Voltometer reads 14v @ fuse box, without jumping around
Alternator is new, but it did the same thing with the old one
Every spark plug wire tests good, ~2k ohms in each wire
new MSD cap/rotor, but it did the same thing with the old one
I've checked every connection that I can find, and checked all the ground connections.
engine vacuum is steady and strong, 22" @ idle

This is seriously starting to get to me though, because I can't figure out what is wrong with it! Somehow I beleive that these things are all related, but I can't pinpoint exactly when it started doing all this. I really hope somebody can help me out here, this little thing is driving me crazy!

 

I can't believe your asking a question? Just kidding. My electronic knowledge is limited I will see what I come up with and get back to you. Later

 

Should I mention engine ground strap to frame and or battery ground to frame not to mention body to frame ground? And your sure its not the regulator or a loose belt? Could the distributor be faulty? Throwing out ideas

 

Ground strap to engine from frame is intact. I replaced the regulator some 8 months ago, but then again I did buy it at Autozone, so anything's possible. I'll go get a swap it for a new one. The only good thing about Autozone is that WHEN their stuff breaks its usually still under warranty. Thanks for the input, I'm trying to actually figure out what's going on before I start throwing parts at it. TK

 

I just thought I would mention the ground strap as many people seem to forget that little thing and come to find out they are having electrical problems of unknown origin. Your whining sound is what I don't understand, that is why I mentioned the distributor. I like the positive outlook on autozone "WHEN their stuff breaks its usually still under warranty". thats a good one

 

I've all but replaced the pickups in the distributor, and reassembled the whole thing looking for this noise, and it just isn't anywhere. I don't know how one could make this noise, but I think the first part I will throw at it will be a fuel pump. I'll stop by Autozone on the way home from work to receive my next faulty replacement part, and hope that gets the job done for the next 7 months.

To expand on my Autozone philosophy, I first bought a replacement starter motor in 1999, the kind with a 1 year warranty. They last approximately 9 months in my 8.6:1 motor, and about 5 months in my newest 10:1 motor. Good news is that I payed $22 for a starter back in 1999, and I havn't paid for one since. Bad news is that having headers makes this extraordinarily easy task become a juggling act, and always results in 2nd degree burns if you're a hard-headed idiot like me and insists on changing it as soon as you get home. Thanks again for the input.

 

I thought maybe the distributor had a bad bearing inside or something who knows? I could be wrong but I don't know either what would whine and cause the alternator light to come on short of the alternator. Now I am interested in knowing what it turns out to be, so keep me updated. Later

$22 and you get a new reman starter for the life of the vehicle sounds like a good program to me. haha

 

I'll throw out some ideas...

I don't remember if the alternator light is a "reverse ground" light like the oil sender. That means if there is something that goes wrong, the idiot light circuit becomes completed through a "grounding" instead of an "open". My gues is that it is a ground-energized circuit. If it is, the wire could be frayed and grounding against the engine somewhere when it is prone to shake or rattle more...during idle and decellerating. This is what happened when I installed an oil pressure gauge...I did not disconnect or tape off the oil sender wiring connector, and it would bounce around from time to time hitting against the intake and would flash on at idle and decelleration.

This could be your problem, because if the alternator idiot light circuit is grounding, your connections could all be good, but some little piece of insulation could be melted, or a loose fray wire from the connecting points could be hitting against a cold or ground spot.

The same thing could be happening to your ignition wires. If your insulation is bad, an ohmmeter reading is not going to tell you anything unless there is a direct contact to ground. You did not say if you replaced the wires recently, so this is based on the assumption that you have not. It only takes one wire that is beginning to "crisp" to arc and cause the random misfire. Again this won't show up in a resistance reading.

The humming noise could be the result of a slightly misaligned pully at any of the drive belt components. On these old Fords, 9 out of ten times if the power steering unit is not making some kind of whistle, hum, or buzz, its either been replaced or is not a Ford. But if a pulley is bent just a little, you'll get some funny noises because it is out of round. This may not effect the performance of an alternator, air pump, or power steering unit, but it might make noise.

I would visually check the pulleys while its running and see if anything looks like it is spinning askew. Or you could use a mechanics stethascope which are less than $20 which might be worth the cost of your continued frustration. If a pully or shaft is bent, you just take out the unit and try to strategically tap the shaft straight with a blunt countersink or screwdriver, and spin and tap until it looks like its spinning the way it should. In other words, don't let the gorilla do the "tapping."

 

Okay, that is a great post. You just reminded me that I also didn't tape off the oil sending unit electrical connection, it just "hangs out" near the fuel pump. Wait a minute....fuel pump....!!!!!!!!. Wow does that make sense. Okay I'm giving that a shot immediately. I'm using FRPP's 9mm wires, but I'm really looking for a good excuse to buy MSD's super conductors.

Question: if a plug wire is arcing, it will certainly show signs of heat damage from the voltage running throgh the insulation, right? I may be able to find which one is doing it if I can spot a burned-looking wire.

 

that or wait until it is dark the look at them, if there is a leak you will see it. later


Those were some good points native gearhead

 

Thanks...glad to help.

After I posted, I went to my favorite thinking spot (ahem) and something came to me (along with certain things going away). I remember how many times I just started "throwing parts at it" in hopes of eventually fixing various problems.

But then I tought about the post, and about the Mechanic's Stethascope, which I don't have yet. Then I thought about all the oddball tools I have bought. Each tool has been used many times over again, but when I bought them, I had only one purpose in mind at the time. You know "stupid little *****" that you think you can do without. I can't remember how many times I have used this telescoping mirror that I originally bought to find the frame VIN. Its a hell of a useful tool in diagnosing problems in blind spots. I think the stethascope is too.

So my "revelation" of the day was: Instead of "throwing money at parts", it would be better if we "threw" smaller amounts at those useful little ***** tools we always talk ourselves out of buying. Its nuts...I never knew how many bolts are 1 1/8 until I bought that $5.00 socket. And I almost passed it by thinking "who wants to waste ANOTHER $5.00". Well now I concluded that spending money on tools is never a waste.

My next out of pocket car expenditure will be for a stethascope!

 

Native Gearhead,

Unfortunately, neither taping up the pressure sender wire nor replacing every single spark plug wire effected the noise or the misfiring. I am seriously going to go buy a stethescope, I'm getting really tired of this noise. If I knew where it was, it wouldn't bother me. It's very existence is defiant to my aspired mastery of my vehicle. Every time I turn the key, it's there, mocking me, laughing at me. You talk about throwing parts at it, I'm fixing to go buy a Painless Wiring complete 18-circuit truck harness and tell that noise to go suck a lemon tree. Meanwhile, I'm about to rebuild my Edelbrock #1406 carb because it's a friggin' monster to tackle on my morning drive, at least until it's completely warmed up.

My favorite little tool that I can't do without:

the $0.99 telescoping magnet. Enough said. I have spent a total of $8 buying replacements, because I always lose them, and I always need them the day after I lose them. TK

 

Couple of suggestions popped up, at night when your parked and the lights are on and you rev the motor do the lights get brighter? And your positive the alternator pulley is in alignment with the belt, and the belt is tight? Just thought I would throw these out there, later

 

I had an 85 F150 with a similar alternator problem and it turned out the plug going to the voltage regulator was loose. If I held it a certain way it cured the problem so I went cheap and just shimmed it to tighten it up against the contacts. Never had another problem after that. Just an idea.

 

...and that fixed an engine misfiring? Just curious, but I havn't tried that yet, thanks for the suggestion! I certainly wouldn't doubt it since I've had to change the voltage regulator in the past.