Idle Drop with Electrical Load
#1
Idle Drop with Electrical Load
After searching and reading, I'm curious about anyone's opinion about my idle.
First - car idles fine, smooth as glass. When it's dark out and I turn on the headlights (or, to a lesser extent, anytime i press the brakes) my idles drops. now, it sits at 800 solid, and when i press the breaks i will drop maybe 50 rpms, but at night with headlights on and such, my idle sits at 700 and will dip to 600 for a second before bouncing back up to 700 or so. put the headlights down, and up my idle goes.
my volt gauge sits at 13 when im driving along without headlights but drops to just above 12 if my headlights are on.
My thoughts were either a sticking BAC, since i have so many miles or my alternator not putting out voltage enough.
First - car idles fine, smooth as glass. When it's dark out and I turn on the headlights (or, to a lesser extent, anytime i press the brakes) my idles drops. now, it sits at 800 solid, and when i press the breaks i will drop maybe 50 rpms, but at night with headlights on and such, my idle sits at 700 and will dip to 600 for a second before bouncing back up to 700 or so. put the headlights down, and up my idle goes.
my volt gauge sits at 13 when im driving along without headlights but drops to just above 12 if my headlights are on.
My thoughts were either a sticking BAC, since i have so many miles or my alternator not putting out voltage enough.
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#11
1986 Mazda Rx-& Non-Turbo
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the taurus alt needs a minor bracket fabbed, and the pully drilled out, and some minor electrical work. its a 140 amp alt, and you can score it cheap at any local junk yard/parts store. I dont remeber the details on the FD alt install, but non of them where to hard.
#13
Money talks-mine says bye
iTrader: (18)
While this alternator issue will improve your charging system, it won't alter your idle problem. Definitely sounds like your BAC isn't working. Easiest thing to do is swap it for a known good one. You could also check the voltage at the connector. What happens when you demate the BAC connector?
#14
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I was experiencing a similar issue with my 86, there is a ground wire from the engine to the body with a slip on connector for the body side i found that in wet weather mine would corrode and need to be cleaned with a bit of sandpaper. i eventually replaced it altogether with a slightly heavier gauge of wire. no idea why this affected me only when i applied the brakes tho. my alt sits at 13+1/2 during daylight driving and just above 12 with fans and lights and wipers and brakes all on.
#18
Cake or Death?
iTrader: (2)
Yeah, looks like it.
Oddly enough, my alternator took a crap yesterday.
It was a FD unit I bought used 3 years ago, one minute it was fine, the next, not.
Naturally, no one in town has one and even a reman from NAPA is @$160, which is way more than I wanted to spend on a motor that's probably getting replaced soon, so I spent a bunch of time on the interwebs researching options.
Turns out, several cars use alternators very much like ours...929's, 626's and even MX-6's.
The MX-6 even uses a v-belt, so the pulley would probably work without swapping to the RX-7 piece.
I pulled one from a mid-nineties 929.
It runs a ribbed, flat belt but my already modified pulley (bored to fit the FD alt) was a perfect fit.
The wiring was plug-n-play for the S5 wiring, absolutely no modification required.
Nominally rated at 90A, my junkyard unit tested at 110A at Autozone (for whatever that's worth).
Cost me $25.
You might consider visiting a junkyard...
Oddly enough, my alternator took a crap yesterday.
It was a FD unit I bought used 3 years ago, one minute it was fine, the next, not.
Naturally, no one in town has one and even a reman from NAPA is @$160, which is way more than I wanted to spend on a motor that's probably getting replaced soon, so I spent a bunch of time on the interwebs researching options.
Turns out, several cars use alternators very much like ours...929's, 626's and even MX-6's.
The MX-6 even uses a v-belt, so the pulley would probably work without swapping to the RX-7 piece.
I pulled one from a mid-nineties 929.
It runs a ribbed, flat belt but my already modified pulley (bored to fit the FD alt) was a perfect fit.
The wiring was plug-n-play for the S5 wiring, absolutely no modification required.
Nominally rated at 90A, my junkyard unit tested at 110A at Autozone (for whatever that's worth).
Cost me $25.
You might consider visiting a junkyard...
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Jeff20B
1st Generation Specific (1979-1985)
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09-16-18 07:16 PM
accessories, accessory, alt, alternator, car, drop, drops, electric, electrical, hailey, idiling, idle, load, rx7, taurus