SOLVED: Brand new alternator junk? (Nope...bad ignition coil)

[ecgreen]

My alternator final crapped out so I put in a new Napa 80 amp (I have a winch). They said it was new and not a reman. The truck now periodically cuts out and bucks under load. This has happened before I swapped the alternator, but only twice in the last 1000 miles! The belt is a bit loose on the alternator, but I doubt that will be a fix. Is it possible I have a bad "new" alternator? If so, how would that be causing my problems?

Sean

 

[fastpakr]

Are you -absolutely- sure you don't have a bad/loose power or ground wire (particularly near the alternator or battery)?

 

[rubydist]

Yes, I have had brand new parts (including alternators) fail in the first 30 days of use.

 

[Uncle Gump]

Did you try testing the alternator?

 

[ecgreen]

Taking all comments into account...I'll get back to ya. Thanks for the 1,000,000,000th time

 

[19Walt93]

More diag is needed, cuts out and bucks sound like ignition problems.

 

[ecgreen]

More diag is needed, cuts out and bucks sound like ignition problems.

Its something, but I don't think it is the new alternator. I just unplugged it and took it for a drive. Exact same performance with the alternator plugged in. Thoughts on where to look next? What to test in ignition system first? (all new high quality plugs already in - everything else is old old old in the ignition system)

 

[fastpakr]

When it cuts out, do you notice other issues (loss of power elsewhere in the vehicle, etc)?

 

[ecgreen]

When it cuts out, do you notice other issues (loss of power elsewhere in the vehicle, etc)?

Good question, and I don't know. I'll take it for a test drive and see if the radio lights cut out. It only cuts out for an instant so might be hard to tell.

 

[Eddo Rogue]

Its happened to me more than once. A brand new (not reman) Bosch lasted me 300 miles and completely died. Another chain parts store house brand was DOA out of the box. I am currently running my original 30 yr old Motorcraft 95 amper, works like a champ.

 

[Shran]

I almost always have alternators and starters rebuilt by a place down the street from my office - 95% of the time they do excellent work but two times they have given me back an alternator that they said was fully rebuilt and working perfectly but was obviously not. Have definitely had many bad "new" ones from parts stores too.

Could that be your problem, maybe? See if it tests good. I had one that would do weird things but only under a heavy load. Was leaking AC voltage (that was one of two rebuilds that failed.)

Wiring, fuel, ignition issues, etc seem more likely given the age of your truck and the presence of the notorious TFI module. Could be a lot of things.

 

[ecgreen]

I almost always have alternators and starters rebuilt by a place down the street from my office - 95% of the time they do excellent work but two times they have given me back an alternator that they said was fully rebuilt and working perfectly but was obviously not. Have definitely had many bad "new" ones from parts stores too.

Could that be your problem, maybe? See if it tests good. I had one that would do weird things but only under a heavy load. Was leaking AC voltage (that was one of two rebuilds that failed.)

Wiring, fuel, ignition issues, etc seem more likely given the age of your truck and the presence of the notorious TFI module. Could be a lot of things.

I am pretty sure it is not the new alternator. I took the truck for a test drive with it unplugged. The truck still randomly bucked under load. TPS tested fine. Wires and expensive spark plugs are new. Rotor cap new. My next stop is the ignition coil. Its 32 years old. TFI will be next on the list.

 

[19Walt93]

Lets get the description a little more detailed. Cuts out would mean the engine stops running while driving with some throttle applied, if that's what it does, does the tach continue to read as you coast to a stop or does it drop to zero as if you turned the key off? If it dies as you slow to a stop with no throttle applied, that's stalling. Bucks means that the engine cuts out briefly then comes back to life as if you turned the key off and back on. Missing or skipping is when (usually)one cylinder isn't running, making the engine shake rhythmically and stutter, like a machine gun for example, and would be felt more severely accelerating. Is the MIL(check engine light) on, and if so, what are the codes?

 

[ecgreen]

B2's on the back burner for a week or so. I have an extra ignition coil, so I might swap that out today as a hail Mary. After I get back to work on it, I'll post up more details.

 

[ecgreen]

Swapped the ignition coil...problem gone. Alternator is fine, just a 32 year old coil starting to malfunction randomly. The Blue Pig lives to drive another day!