12 V conversion AC C misfires
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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=159595
Printed Date: 10 Nov 2024 at 3:39pm
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Topic: 12 V conversion AC C misfires
Posted By: Cooper2
Subject: 12 V conversion AC C misfires
Date Posted: 02 Apr 2019 at 6:40pm
| Recently did a 12 volt conversion on my 49 C. New 1 wire alternator was not self exciting. Tractor ran smooth while alternator was not excited. I then wired the alternator pigtail #1 and #2 with alternating warning light. Alternator now excites and charges but tractor runs erratic with misfiring. I have checked and double checked my wiring with multiple online wiring diagrams and all is correct per the references. Could the misfire be due to a faulty alternator voltage regulator? |
Replies:
Posted By: Cooper2
Date Posted: 02 Apr 2019 at 6:44pm
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I should have mentioned this is a 35 Amp mini Chevy alternator with built in regulator. After market eBay purchase. |
Posted By: jaybmiller
Date Posted: 02 Apr 2019 at 6:45pm
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Disconnect the alternator feed to battery then start and run the tractor. If she's purring like a kitten , you've got your answer.....'something' wrong in the alternator.. ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: Cooper2
Date Posted: 02 Apr 2019 at 6:47pm
| I did that and it runs great, so your are confirming my thoughts about the alternator. |
Posted By: jaybmiller
Date Posted: 02 Apr 2019 at 7:01pm
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I've put the CS-130 series on 4 D-14s and never had a problem. Gotta be 'someting' inside the alternator, maybe a 'load' that drops the voltage to the coil way down every so often... Jay ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: DougS
Date Posted: 02 Apr 2019 at 7:37pm
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Probably a bad diode in the alternator. The alternator is making dirty DC. |
Posted By: PaulB
Date Posted: 03 Apr 2019 at 1:09am
That’s why I stay away from fleabay!  You are morelikely to get a piece of junk that the seller knew was defaulty as something usable👎------------- If it was fun to pull in LOW gear, I could have a John Deere. Real pullers don't have speed limits. If you can't make it GO... make it SHINY |
Posted By: DougS
Date Posted: 03 Apr 2019 at 3:55am
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At least you have a core to trade in now when you go to an auto parts store and get a rebuilt alternator. |
Posted By: Krazy Karl
Date Posted: 03 Apr 2019 at 6:55pm
| What model of alternator was it. I was looking at a couple on there and don't want to end up with same problem |
Posted By: Steve in NJ
Date Posted: 03 Apr 2019 at 7:45pm
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When's the last time you tossed spark plugs in it? Might need a good tune-up. Never heard of an Alternator causing a problem with the ignition where it makes the engine miss or run bad. Check your firing order also. You might have a plug wire on wrong. Draw test the Battery. Make sure you don't have a bad cell. Put a voltmeter on the system. What's the output of the Alternator? Is it charging normally, (13.9-14.5/14.2 ideal) overcharging, undercharging, not charging at all? Coil wired backwards? Dirty DC? Hmmmm... there's one I haven't heard before. You have something wrong there but it ain't your Alternator causing it... Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: DougS
Date Posted: 04 Apr 2019 at 3:58am
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This very same problem showed up on another thread several months ago. I don't know what he did to fix it. This is why I like to see people report back when the problem is solved. |
Posted By: Cooper2
Date Posted: 04 Apr 2019 at 7:53pm
| I replaced the alternator and the problem continued--misfiring when the alternator was charging. The brand new 12v ignition coil with an internal resistor I installed turned out to be the issue. I replaced it with another new 12 v coil and now the tractor runs great and the battery is charging. The extra voltage when the alternator was charging must have thrown it over the edge. |
Posted By: Steve in NJ
Date Posted: 04 Apr 2019 at 8:09pm
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Glad to hear you dialed in on the problem! I knew it had to be ignition or a wring issue somewhere. I knew it wasn't the Alt. Great job diagnosing! Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: Gerald J.
Date Posted: 04 Apr 2019 at 10:33pm
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A 6 volt coil with 12 volts applied is sure to overheat and then short turns in the windings to hurt ignition. Reversed polarity also hurts ignition. It was surely positive ground when 6 volts and if the coil primary terminals weren't swapped when converted to 12 volts that reversed coil polarity hurts ignition. Gerald J. |