Gen 2 light comes on at idle

[niferous]

OK ever since I bought my truck I have had problems with the Gen 2 light coming on when the truck goes to idle. As soon as I hit the accelerator I the light goes off. I replaced the belts with Gates belts and they are all tight. I also had the passenger side alternator rebuilt. But still the light comes on.

I will say that before I had the alternator rebuilt the light would come on strong immediately and stay on as soon as I let off the accelerator. Now it will come on dim but will eventually come fully on. My voltage does drop from the white line but it stays in the green.

One other symptom is that first thing in the morning or just when the motor is cold none of this happens. Both lights go out and stay out. When the motor warms up the Gen 2 light comes on at idle again.

Yet another symptom that may or may not be related is that my voltage is always in the yellow when I start it up cold. It does start but the voltage stays in the yellow until it warms up.

Also in case it may have an effect on things my truck came with Optima Red Top batteries when I picked it up at GL. I don't know how old they are and they were dead when I got the truck.

 

[doghead]

Get your batteries tested.

 

[AJMBLAZER]

What he said.

My Gen 1 light comes on occasionally when I start Big Ugly but it doesn't always and all I have to do is tap the pedal and it goes away. That is fairly normal. Yours sounds a bit more serious.

 

[niferous]

I guess I was hoping it wouldn't be that. Optimas ain't cheap and I would like to keep those in the truck. However I will take them out and get them checked.

 

[Recovry4x4]

Almost every CUCV I've ever had were set for a low idle, too low for my likings. In the AM when your truck is cold, the high idle solenoid is energized and your idle is bumped up a bit keeping the alt spinning fast enough to keep up. While sitting in the truck, idling in gear, is it rattling the heck out of the truck? I'd bump up that idle just a little bit and see what you get. Smoother idle (which saves on bulb life) and no gen light I bet!

 

[blzrgb]

 

[niferous]

While sitting in the truck, idling in gear, is it rattling the heck out of the truck? I'd bump up that idle just a little bit and see what you get. Smoother idle (which saves on bulb life) and no gen light I bet!

Yeah my truck shakes like a leaf on a tree when at idle. I didn't realize this was probably due to a low idle. Also it makes sense what you are saying about the solenoid coming on in the morning. I had not thought about that.

How do I bump up the idle?

 

[Recovry4x4]

There is an adjustment screw on the drivers side of the pump, kinda low. You have to shoot a long screwdriver in there to adjust it. I do a quarter turn and take a little ride to see how it acts. Should fix your issue! The old junker hubs show up yet?

 

[niferous]

Thanks Recovery I will try that out tonight.

Yes they did and I feel bad now because I forgot to let you know. I work full time and I'm getting my masters and as it's finals time my brain is very fried. I haven't had time to look at them yet and I need to find a schematic so I can make sure all the parts are there. I hope to repay the favor someday and if I can send you money for shipping let me know!

 

[Recovry4x4]

You saved them from the trash can! I need nothing for them. No worries!

 

[muta4warrior]

OK ever since I bought my truck I have had problems with the Gen 2 light coming on when the truck goes to idle. As soon as I hit the accelerator I the light goes off.

One other symptom is that first thing in the morning or just when the motor is cold none of this happens. Both lights go out and stay out. When the motor warms up the Gen 2 light comes on at idle again.

Also in case it may have an effect on things my truck came with Optima Red Top batteries when I picked it up at GL. I don't know how old they are and they were dead when I got the truck.

Mine will come on when I first start up then go out as soon as I hit the gas, I am good for about 15-20 mins till everything start to warm up. When I let off the gas the Gen 2 light will glow for a split sec. then go out.. Mine have Interstate batteries.

 

[sparky1]

OK ever since I bought my truck I have had problems with the Gen 2 light coming on when the truck goes to idle. As soon as I hit the accelerator I the light goes off. I replaced the belts with Gates belts and they are all tight. I also had the passenger side alternator rebuilt. But still the light comes on.

I will say that before I had the alternator rebuilt the light would come on strong immediately and stay on as soon as I let off the accelerator. Now it will come on dim but will eventually come fully on. My voltage does drop from the white line but it stays in the green.

One other symptom is that first thing in the morning or just when the motor is cold none of this happens. Both lights go out and stay out. When the motor warms up the Gen 2 light comes on at idle again.

Yet another symptom that may or may not be related is that my voltage is always in the yellow when I start it up cold. It does start but the voltage stays in the yellow until it warms up.

Also in case it may have an effect on things my truck came with Optima Red Top batteries when I picked it up at GL. I don't know how old they are and they were dead when I got the truck.

thats interesting,on my m008 when the motor is cold the gen lights go completely black upon increasing the rpm.but when warm the gen 2 light comes on very dim and when the fan is on low and gets a little brighter at higher fan speeds.its more noticeable at night.no ill effects than i'm aware of.

 

[niferous]

Which way should I turn the screw? Counter or clock wise?

 

[CUCV85]

Which way should I turn the screw? Counter or clock wise?

turn clockwise I believe
Just turn it,
USE A BRIGHT LIGHT TO SEE DOWN UNDER THE COLD START SOLENOID.
you will hear it idle up as you turn it.
You are bumping up the idle about 200-400 RPM just listen for it.

Next push in the long screw adjustment for the fast idle solenoid -
You will see the difference between the adjustment you made to the low idle and fast idle from the cold start solenoid - which can also be adjusted turn in or out.

 

[niferous]

I tried adjusting the idle and it had a result but not the one I was looking for exactly. I got the truck started and as usual the light came on so I adjusted that screw. The only effect it had was that now instead of coming on and staying on it blinks of and off at idle. One thing that went well was that the voltage no longer drops. I had to adjust the screw all the way down to get it to do this though. It actually feels a little peppier now too.

While test driving it I went by O'Reilly and had them check both batteries and both tested good.

Any ideas what to check next?

 

[max1008]

Same exact problem. Charging fine. Problem.started after I replaced alternator for a used one.

 

[doghead]

Rebuild your alternator, if it does not go out above about 800 rpm.

 

[scottladdy]

27SI Alternator Manual

Rebuild your alternator, if it does not go out above about 800 rpm.

I've attached the manual for the stock CUCV alternator for most variants. Gen light issues (flicker at low RPM) may be indicative of a shorted stator. See page 7 of the attached manual. Most shops don't replace the stator or rotor in a typical rebuild. A lot of shops will only replace the parts that fail testing, regardless of age. Shops will also often use a simple continuity check to determine if there are shorts in either the stator or rotor windings. I have had stators that the alternator shop tested and validated as good show a high resistance short to the core.

I recommend considering rebuilding the alternator yourself. Invest a few $'s in the rebuild kits and a good multimeter. You should have the meter for other electrical repairs anyway.

I hope this helps ...

 

[max1008]

thats on my list for this week, ill give it a whirl

 

[harmon]

What you have said is exactly my problem also. I had both batterys test and are very good. I can't figure it out.