Flat Work Posted March 30, 2018 Share Posted March 30, 2018 Well, I lit the Mack up a couple of days ago. It had been sitting for a couple of months. I have either a very low alternator output, or none at all. It shows about 11 volts at an idle. It steps up to 12-12.5 volts if you give it some rpm's. The little lightening bolt on the dash stays on at and idle, but will go out after increasing rpm's as well. I have done zero checking on the system anywhere as of yet. Any suggestions exactly where, and how to start? I did have to boost it to start it. Thanks. Quote Link to comment Share on other sites More sharing options...
41chevy Posted March 30, 2018 Share Posted March 30, 2018 (edited) I would start with cleaning the battery connections and the battery ground to chassis. Edited March 30, 2018 by 41chevy Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
Mack Technician Posted April 4, 2018 Share Posted April 4, 2018 (edited) I’d send a defibrillator shock into the alternators field terminal and see if it lights off. Had it work before, not much to lose. Use a battery charger to do it. Edited April 4, 2018 by Mack Technician Quote Link to comment Share on other sites More sharing options...
Flat Work Posted April 5, 2018 Author Share Posted April 5, 2018 6 hours ago, Mack Technician said: I’d send a defibrillator shock into the alternators field terminal and see if it lights off. Had it work before, not much to lose. Use a battery charger to do it. What's the process for doing that? Quote Link to comment Share on other sites More sharing options...
MACKS Posted April 5, 2018 Share Posted April 5, 2018 Check the belts.. 1 Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted April 5, 2018 Share Posted April 5, 2018 2 hours ago, Flat Work said: What's the process for doing that? There is one lead going to alternator, but how many unused terminals are on the back of your alternator? Quote Link to comment Share on other sites More sharing options...
Flat Work Posted April 7, 2018 Author Share Posted April 7, 2018 On 4/4/2018 at 10:14 PM, Mack Technician said: There is one lead going to alternator, but how many unused terminals are on the back of your alternator? I don't know right now. The truck is parked over at a friend's farm. I left it sitting there after I got done helping him get his grain up last December. I've had my kids all week for spring break. I'm heading over there next week to get the truck around for spring. I'll let you know what I find. Quote Link to comment Share on other sites More sharing options...
Flat Work Posted April 11, 2018 Author Share Posted April 11, 2018 On 4/7/2018 at 8:17 AM, Flat Work said: I don't know right now. The truck is parked over at a friend's farm. I left it sitting there after I got done helping him get his grain up last December. I've had my kids all week for spring break. I'm heading over there next week to get the truck around for spring. I'll let you know what I find. There are 2 unused terminals. Both have a rubber cap on them. I have the batteries out charging right now. I'll let them slow charge until tomorrow morning, and go get them tested. The drive belt is tight. The connections all look good and clean. The alternator is a Delco 22si. If I determine it's bad, is there anything special about it? Is it on a standard frame? All the replacement ones I've seen seem to be between 150-220 amps. But I don't know for sure how big the one that's on it is. Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted April 11, 2018 Share Posted April 11, 2018 (edited) Leave rubber booted posts alone, the third blade style connector to the right (as viewing from rear) is the field monitor connection. Leave it alone unless you are going to condemn it. Did you test (alternator) with a fluke meter or some reliable source beside the dash? Certificate of death requires a second opinion. Go right to the alternator and check it directly at the main terminal out. Batteries are dead, that is a first indication of something potentially wrong. Most battery shops will have a smart tester you can use. Fully charge, let them stabilize and test them. Check the battery for water. If the water is low only add distilled water which will have no mineral/metal content. You can get that alternator at NAPA or many other sources beside OEM. Your old alternator will likely have the Amps listed/engraved on it somewhere, otherwise go with the 150 or 145, that is more than sufficient unless you are running a fridge in your truck. Remember one customer cutting a massive hole in his sleeper back and shoving a full size refrigerator freezer into his truck. Riveted and goo-patched some tin over the hole, pretty wild. That brother needed a 220 alternator and a fire extinguisher to spray it with. Edited April 11, 2018 by Mack Technician Quote Link to comment Share on other sites More sharing options...
Flat Work Posted April 13, 2018 Author Share Posted April 13, 2018 It was combination of both. The alternator is dead, and the batteries are weak. I picked up 2 new batteries yesterday. And I'm seriously considering adding 2 more. One thing I've learned from living in Michigan for 49 years- you can never have too much cold-weather cranking power. I got the alternator off yesterday. Damn- that was a job! It's a standard Delco 22SI. 150 amp. I'm going to my local starter/alternator shop this morning. I'm going to talk to him about a quality replacement in the 200 plus amp range. I don't have a refrigerator in there yet, but I might add one later. My main concern is in getting a quality alternator that hopefully will outlast my ownership of the truck. That thing was a pain in the ass to remove. And I don't want to have to do it again!!! 1 Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted April 13, 2018 Share Posted April 13, 2018 (edited) One thing I've learned from living in Michigan for 49 years- you can never have too much cold-weather cranking power. . Michigan starters dream big........ just like any chubby Yuper....... All-You-Can-Eat buffet. Alternator will keep buying the groceries. Edited April 13, 2018 by Mack Technician Quote Link to comment Share on other sites More sharing options...
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