A/C idle up?

[tweakedlogic]

Isn't the motor supposed to up the idle a couple hundred RPM when the A/C is on? If not it should.
Is there something to adjust or should be checked for this?

It is not the IAC. while searching for my idle up I got lots of hits for the IAC. so I cleaned it and it did nothing for me.

The reason I need it is because with my e-fan, and the a/c on 3 or higher, my voltage drops to about 9 volts. less if the headlights are on and I'm depressing the brake pedal. Unless I heel/toe the brake and accelerator to keep the idle @ around 1000. (5 speed)
My alternator tests good and I don't have any trouble as long as the motor is @ or above 1000 RPM.

 

[Rick]

This thread has some good info about the charging system in general:
http://www.explorerforum.com/forums//showthread.php?t=266963

I think that the electric fan may be overloading your stock alternator. Do you know how may amps yours draws? I have seen them draw as much as 40a.

 

[Anime]

The idle shouldn't go higher, but the ECU and IAC should do what's needed to keep the idle speed correct, even under the A/C load. If the idle speed goes down below normal, and doesn't bump back up quickly, there is a problem. Cleaning the IAC doesn't always work, unless you fully disassemble and rebuild it. Sometimes just spraying cleaner in there can mess up the moving parts, and either have no effect or make things worse.

If it's the stock 95A alternator, it makes sense that the 30-40A fan, plus the A/C load, plus the draw of the headlights and all other lights, would tax it beyond its output, especially at idle, when the alternator output is lowest.

A fresh new alternator (or a rebuild) might help things, but your best bet is probably going to be upgrading to a 130A alternator. It doesn't put out much more at idle than the 95A, but it should still help.

The other cheaper solution is a smaller alternator pulley. These are found on a few aftermarket alternators, you can probably get one at a starter/alternator shop and have them swap it out with the stock one. This will bump up the idle output a bit, but in exchange for making the alternator turn faster, it will also wear out that much quicker.

 

[tweakedlogic]

thanks guys. it looks like I will be looking for an alternator. Isn't there one from another truck that bolts right up and has higher output?

 

[Anime]

The 130A alternator from an Explorer Limited bolts right up. You can get them at any parts store. Just specify you want the 130A and not the 95A. It's a bigger case, but the bolt holes are the same, the pulley is the same, it's just a bigger alternator.

You can find even higher amp alternators, 160A, 200A, etc, but they are more expensive, and usually unnecessary unless you either have big electrical demands (lights, stereo) or just want overkill.

 

[Nedwreck]

My explorer has the bracket and hi-amp alt. from a 95 limited... which is probably a waste since I don't have any extra load from a e-fan or anything.

anyway... if you can measure the diameter of your stock pulley, I might have a slightly smaller one, which would give you a bit more alt. speed.

when I find my calipers, I'll measure one of these and post.

 

[tweakedlogic]

anyway... if you can measure the diameter of your stock pulley, I might have a slightly smaller one, which would give you a bit more alt. speed.

Thanks Nedwreck. That is a very nice offer. I may have to take you up on that.

What part of KY are you in? I was in Paducah and Murry for a while. Alcohol was too hard find though, had to leave.

 

[Anime]

It's not a waste, the big case of the 130A is said to let it run cooler than the small case of the 95A...though my stock 95A lasted over 200,000 miles, and would have kept going if I hadn't taken it off to replace the brushes and had it broken at a shop when I took it in for a rebuild.

The smaller pulleys are only slightly smaller, but it's what the aftermarket alt's use to put out slightly more amps to meet their claimed output, so they must be at least somewhat effective.

 

[Nedwreck]

Thanks Nedwreck. That is a very nice offer. I may have to take you up on that.

What part of KY are you in? I was in Paducah and Murry for a while. Alcohol was too hard find though, had to leave.

I'm about 40 mins east/north eat of Louisville.

There is NO shortage of alcohol around here - ever.

(I quit drinking, oddly enough. heh)

.

I picked up a alt. out of the pile that I ~think~ is from a first gen.... its pulley appears to be 64mm/2.52in. roughly.

The smaller pulleys I have are 61.6mm/2.42in. roughly.

Measurements are "approximate" lol, and measured across the top of the pulley belt area (not the valleys).

I played around with a pulley drive speed thing on the web, I think this would be enough pulley to fix your problem but not overspeed the alt. at high RPM's, and I'm sure you wouldn't need a new belt.

 

[Nedwreck]

It's not a waste, the big case of the 130A is said to let it run cooler than the small case of the 95A...though my stock 95A lasted over 200,000 miles, and would have kept going if I hadn't taken it off to replace the brushes and had it broken at a shop when I took it in for a rebuild.

The smaller pulleys are only slightly smaller, but it's what the aftermarket alt's use to put out slightly more amps to meet their claimed output, so they must be at least somewhat effective.

yeah the big alt is very noticeably larger than a first gen alt....

It required the bracket from the '95, and the tensioner is now under the alt instead of "beside" it. Oddly, I still use the same belt as the first gen unit.

That big alt from the 95 runs 14.4 volts ALL the time - turn on the AC, headlights, role a bunch of windows up or down - and it barely varies at all. I actually thought about underdriving it a tad. lol