LOW RPM's (Has this happend to anyone else?)

[Ultim8SVT]

Ok guys I decided to open a thread specifically for this reason. Truck idles between 400-500 RPM's.



Ok, let it be known, the truck idles SUPER smooth at 400-500 RPM's. However at these lower RPM's the alternator is failing & the A/C stops working.

Today I cleaned the throttle body & the Mass Air Flow sensor. Nothing. It's still the same.







Has this happened to anyone else? I don't want to start buying parts & swapping parts on it just to swap & end up on the same boat.

 

[chauncey0337]

Mine idles right around 500 too. How do you know the alt is failing?

 

[LOWHOE775]

So i had that happen to me and i found out that my alt was not charging as it should. So i bought a new one and the rpm jumped up to like 700-800. Che k your battery as well hope this solves your problem

 

[imi4tth3w]

definitely could be something going out putting strain on the motor.

 

[Ultim8SVT]

Interesting. The battery has a 10/2010 date so it's just about 3 years old. The dash board volt meter is showing 14.5 volts - 15 volts but within 24 hours the battery is just about dead. I assumed the alternator wasn't working because the RPM's are low when it just might be the other way around. I'm going to swap the battery in the next couple days. Let's hope that's the case.

 

[LOWHOE775]

Yea start with the simple stuff and less money involved. It has to be one of the two. I have a audio system in mine and that is what fried my alt to much strain on it made it go out.

 

[Ultim8SVT]

Yea start with the simple stuff and less money involved. It has to be one of the two. I have a audio system in mine and that is what fried my alt to much strain on it made it go out.

Thanks Low. Yeah. Going to a local auto parts store with the battery to get it tested.

 

[576575]

I get worried when it's NOT idling at 500-700, similar thing happened to me as LowHoe stated... ever try and see what happens when reving the engine a couple times? couldn't hurt to try

 

[Ultim8SVT]

ALright guys, battery tested ok but crank amps were low(550). My stepfather had a battery with 700 crank amps. No more dead battery. Howevery my RPM's are still the same.

I get worried when it's NOT idling at 500-700, similar thing happened to me as LowHoe stated... ever try and see what happens when reving the engine a couple times? couldn't hurt to try

That's kind-of my first instinct. Do it all the time. Doesn't do anything.

 

[LOWHOE775]

Ok now you know you have a good battery. Now take the alternator off and take it to auto parts store get it tested. Free at auto zone or orielly. I dont like pep boys i never go there.