Author Topic: alt regulator question  (Read 686 times)

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pioneer4x4

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alt regulator question
« on: August 07, 2009, 07:00:25 PM »
ive had this alternator for about 3 months in my 2.5 xj tbi, ever since i put it in the voltage gauge was always going from 10-14 volts, when it dropped down to 10 the only thing that would happen is my lights would dim, but id rev it up and bring it up. however recently my idle is a little erratic, bogging down. had the alt tested at orielly and said the voltage regulator in my alt is bad. could this be messing with my idle, not producing enough spark or something? also it seems lately everything i touch under the hood is very very hot, even on a short trip?

pioneer4x4

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Re: alt regulator question
« Reply #1 on: August 07, 2009, 08:01:45 PM »
well i thought id get a second opinion, went to autozone and had them test it, they said everything tested out fine. so now im really not sure. although autozones machine they hooked up to it was a lot more elaborate than oreillys, so i think id believe theirs. they said they could bench test it, so i guess ill pull it and take it in. on a side note do any of yall use any additives before oil changes? i use seafoam, just wanted to see what everyone else uses or has had good results from. thanks

Offline sharpxmen

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Re: alt regulator question
« Reply #2 on: August 07, 2009, 08:11:16 PM »
i think on mpfi engines (not sure if yours is like that) the field control comes from the PCM (ECU) - there are two 50 amp fuses that are inline between the alternator and the battery, i had one blown and only one of them was working and it kept failing on me when i was in need of more than 50amps - check those as well, maybe one is dead and the other one sometime looses contact (you could run a wire from the alternator to the battery for a test though, to see if you still have the problem -needs to be thick enough, same as the existing one).
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

pioneer4x4

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Re: alt regulator question
« Reply #3 on: August 07, 2009, 08:30:27 PM »
i think i will go ahead and replace all 3 of those relays like you said, if nothing else it will be cheap preventive maintenance. but im a little confused on what you said about running a wire from the alt to bat, in my set up the power wire from alt goes the a starter relay (which looks like its original from 1986) by the battery and that is connected to battery, its like a main power junction. do those ever go out or start to stick? i would assume eventually its bound to go bad especially after 23 yrs. and i have upgraded all my wires to 00 welding cable.

Offline sharpxmen

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Re: alt regulator question
« Reply #4 on: August 07, 2009, 10:34:02 PM »
i think i will go ahead and replace all 3 of those relays like you said, if nothing else it will be cheap preventive maintenance. but im a little confused on what you said about running a wire from the alt to bat, in my set up the power wire from alt goes the a starter relay (which looks like its original from 1986) by the battery and that is connected to battery, its like a main power junction. do those ever go out or start to stick? i would assume eventually its bound to go bad especially after 23 yrs. and i have upgraded all my wires to 00 welding cable.
nevermind then, '86 is different - i was talking about 91-95. from what you said the alternator is not fused to the battery, so unless you have a bad connection from the alt to the starter wire you were right in taking the alt for a check (sounds like the regulator in this case) - I'm not familiar with 86 but i am just guessing it has an integrated regulator, could also be the brushes though - i'd take it for a check like you said
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end