More electrical fun (charging System)
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More Turbo
Joined: Mar 2003
Posts: 665
Likes: 6
From: Detroit suburb
More electrical fun (charging System)
You guys have helped - with one of the problems - found a broken wire under relay for EEC. Now runs but have a problem with charging. Gauge is indicating about 10 amps, tested at local Autozone - they confirmed at about 11.3 to 11.6 amps. (This truck is a 94 f150 5.0 4 wd). Anyways it appears that there may be a problem with the gauge or the rheostat ? that may be a part of it. Red wire (green stripe) going to it has 12 volts, Green wire (red stripe) coming off of it - and going to alternator has only .8 to .9 volts. It is supposed to be hot in run or start position. Wondered if anybody else had this problem and what the fix was ? May require a new instrument cluster, hope not .....
Elder User
Joined: Mar 2004
Posts: 580
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From: Chippewa Falls, WI
Since your cluster reading matches the test at autozone I wouldn't think there is anything wrong with your cluster. Did you have them check the alternator individually? It would sound to me like it might be out. Also on some of these trucks the wiring plug to the alternator MUST be changed when it is unplugged or it can burn out.(it has been a while but I think it is the 4.9 and the 5.0 with the large rectangle plug) If you have one of those vehicles it may have been messed with and isn't getting a good connection. have the parts store pull the alternator that fits your truck off the shelf, a new plug would be in the box if it is required for your truck. The plug can be purchaced separate from the alternator from the HELP! line most stores carry. A good store will know what you are asking for.
Just a couple of things to check.
Just a couple of things to check.
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More Turbo
Joined: Mar 2003
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From: Detroit suburb
Kell:
Ok, thanks for the plug tip. I was listening to a Sat morning talk radio "The Car Show" and they may have said something like that as well. This plug has 3 wires, has the dielectric grease there - but doesn't have a positive snap to keep it in place - it seems to come off the alternator easier than normal .....
Ok, thanks for the plug tip. I was listening to a Sat morning talk radio "The Car Show" and they may have said something like that as well. This plug has 3 wires, has the dielectric grease there - but doesn't have a positive snap to keep it in place - it seems to come off the alternator easier than normal .....
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More Turbo
Joined: Mar 2003
Posts: 665
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From: Detroit suburb
Kell, 1966 Tbird:
Ok, I changed out that plug today and used a small file on the contact points in the distributor (pins), STILL NO LUCK (this is a 94). I also have a 92, but that one has slightly different electrical connections - appears alternator a little different.
So, any more ideas ??
Ok, I changed out that plug today and used a small file on the contact points in the distributor (pins), STILL NO LUCK (this is a 94). I also have a 92, but that one has slightly different electrical connections - appears alternator a little different.
So, any more ideas ??
Elder User
Joined: Mar 2004
Posts: 580
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From: Chippewa Falls, WI
Did you ever have your alternator tested off the truck? If not I would start there. you might have a bad voltage regulator like 1966tbird suggested. After that I would start tracing wires as best you can. you might have a melted/worh thru wire someplace between your alternator and the dash.
Posting Guru
Joined: Dec 2006
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try putting a ground wire from the engine to the frame this is what i eventually did to mine and that fixed everything
but i did this after a new alternator battery voltage regulator battery cables and alternator plugs
but i did this after a new alternator battery voltage regulator battery cables and alternator plugs
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Elder User
Joined: Nov 2005
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The green wire with a red stripe is the one that "turns on " your alternator. If you don't have 12 volts there when the key is on. Don't work on anything else. You will never get the system working until you solve this problem.
Sorry I can't help more.
Frank
Sorry I can't help more.
Frank
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Thread Starter
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More Turbo
Joined: Mar 2003
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From: Detroit suburb
Ok, frank Thanks. I just wonder, what part of the sytem or what wire tells the voltage regulator how much output is needed back to the battery ? This green / red stripe wire comes from the gauge and if this is not the one - and this needs to be 12 V, perhaps this is all I need to know, but just curious .... Appears I need to pull instrument panel back out to see where the voltage changes (before or after the gauge) .....
Elder User
Joined: Nov 2005
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I think you have a 3G alternator on your 94.
Here is a link to the wiring for a 3G.
http://fordfuelinjection.com/public/...ALT_wiring.gif
The voltage is measured right at the output stud.
Looks like the wire is Yellow with a white stripe.
Is it possible you have a bulb burned out in the instrument cluster?
Good Luck Frank
Here is a link to the wiring for a 3G.
http://fordfuelinjection.com/public/...ALT_wiring.gif
The voltage is measured right at the output stud.
Looks like the wire is Yellow with a white stripe.
Is it possible you have a bulb burned out in the instrument cluster?
Good Luck Frank
Cargo Master
Joined: Sep 2004
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Bypass your battery cables with jumper cables and then re-test. I was having problems with my voltmeter needle fluttering. After replacing my positive cable (corrosion where copper meats lead), the problem went away.
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More Turbo
Joined: Mar 2003
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From: Detroit suburb
Frank:
Thanks for that diagram. One question - am I correct to assume the flow of current is from 20 amp fuse thru ignition switch (12 volts) then to gauge, continuing with 12 volts to the alternator (or might it change down in voltage after gauge) ? Then the alternator and generator kicking out about 14 volts back to battery ...... I spent a few minutes with it tonite, battery was a little discharged 11.7 volts non running, 11.3 running - so not charging yet ...
Thanks for that diagram. One question - am I correct to assume the flow of current is from 20 amp fuse thru ignition switch (12 volts) then to gauge, continuing with 12 volts to the alternator (or might it change down in voltage after gauge) ? Then the alternator and generator kicking out about 14 volts back to battery ...... I spent a few minutes with it tonite, battery was a little discharged 11.7 volts non running, 11.3 running - so not charging yet ...
Elder User
Joined: Nov 2005
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I'm not an expert, but as far as I know, the green/red stripe wire has to deliver 12 volts to the alternator.
You could test everything after the wire from the voltmeter by temporarily splicing a wire from the positive side of the battery, into the green/red stripe wire at the alternator. Then check the volts at the battery with the engine running. If you get around 14volts the alternator , regulator, all the wires and connections are good. It is just waiting for 12 volts with the key on to get everything going. Don't leave the temporary wire connected very long with the engine off. This will drain the battery and perhaps get it really hot. It is just there to test everything.
Good Luck Frank
Good luck Frank
You could test everything after the wire from the voltmeter by temporarily splicing a wire from the positive side of the battery, into the green/red stripe wire at the alternator. Then check the volts at the battery with the engine running. If you get around 14volts the alternator , regulator, all the wires and connections are good. It is just waiting for 12 volts with the key on to get everything going. Don't leave the temporary wire connected very long with the engine off. This will drain the battery and perhaps get it really hot. It is just there to test everything.
Good Luck Frank
Good luck Frank
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More Turbo
Joined: Mar 2003
Posts: 665
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From: Detroit suburb
Frank:
Thanks again.
I might check with an alternator rebuilding shop (not sure if they will know). But if normal current to alternator thru this wire is significantly less than 12 volts, aren't I risking screwing up internals of alternator/voltage regulator by doing what you've suggested ? I am not sure what the 510 ohms symbol means at gauge - per your diagram. Not sure if somebody can test theirs - if they have the same as mine. Truck doesn't need to be running, only key on, and plug in alternator removed with DC volt tester set to higher than 12 volts - to check the reading from the green wire / red stripe ......
I guess looking for confirmation of what you have suggested ...
Thanks again.
I might check with an alternator rebuilding shop (not sure if they will know). But if normal current to alternator thru this wire is significantly less than 12 volts, aren't I risking screwing up internals of alternator/voltage regulator by doing what you've suggested ? I am not sure what the 510 ohms symbol means at gauge - per your diagram. Not sure if somebody can test theirs - if they have the same as mine. Truck doesn't need to be running, only key on, and plug in alternator removed with DC volt tester set to higher than 12 volts - to check the reading from the green wire / red stripe ......
I guess looking for confirmation of what you have suggested ...