my car has been sitting for about 3 weeks so took it out for gas tonight and the lights are very dim and the idle is ruff like it wants to die when the lights are on. the ampmeter is showing between the middle and far left and barely rises when its reved up. i noticed the last time i drove it it was raining and with all the wipers and lights on it would die if i let it idle. runs fine with all accesories off. i replaced the volt reg last year also its a 73 318 factory electronic ignition all parts replaced in last year. could my alternators low charge be causing the running issues? and if i replace it do i need the 50 or 60 amp alt. all wiring is great thanks.
alternator causing bad idle??
- Thread starter rigrunner
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67Dart273
Well-Known Member
I spose it's possible that the battery is far enough down, and with the alternator not putting out much at low speed.
ONE THING you need to do, is related to the problem that time after time keeps showing up, and that is, voltage drop in the system harness and connectors.
With the car doing the best you can for idle, measure the battery voltage AT the battery, and then at the ballast resistor, or better yet, measure the drop directly
To do that, put one probe right on your battery pos. post, the other on the "dark blue" supplying ignition voltage to the ballast.
With the thing idling very slow and low alternator output, you might just find it's got a lot of drop, there.
You have an AM radio? It sound OK? Another possibility is that one or more diode/ winding is failed in the alternator, and this will not ONLY cause low amperage, but a lot of "hash" (AC ripple) on the 12V system. It is possible that this can interfere with the ignition system.
ONE THING you need to do, is related to the problem that time after time keeps showing up, and that is, voltage drop in the system harness and connectors.
With the car doing the best you can for idle, measure the battery voltage AT the battery, and then at the ballast resistor, or better yet, measure the drop directly
To do that, put one probe right on your battery pos. post, the other on the "dark blue" supplying ignition voltage to the ballast.
With the thing idling very slow and low alternator output, you might just find it's got a lot of drop, there.
You have an AM radio? It sound OK? Another possibility is that one or more diode/ winding is failed in the alternator, and this will not ONLY cause low amperage, but a lot of "hash" (AC ripple) on the 12V system. It is possible that this can interfere with the ignition system.
i do have an am radio. it sounds great when the car is off but when its running it sounds terrible and wont keep a signal. tommorow im gonna check all connections and then take it and get the alternator tested. just figured alternator cause it all works fine if the access are off. thanks
checked the wiring and found the nut for the main feed wire has come off and the wire was just sitting on the stud. put a nut on it and fixed. must of been that way a while the wire end had cut the stud almost in 2.
67Dart273
Well-Known Member
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