Hey guys I have an electric water pump on my car so I wanted to run a shorter belt and delete the belt around the tensioner and EWP for looks and a little less parasitic loss. Basically the belt I wanted would have run around the power steering pump, alt, crank and then the idler. I found the correct belt length and it seemed to fit good and tight. However when I started the car the alternator simply wont charge. I even tried a slightly longer belt to see if the first was too tight and got nothing.

If I put the original length belt back on it charges fine. Alt is a truck unit with the stock pulley and the balancer is an ATI 10%. Any ideas why this is happening?

 

Without seeing how you routed the belt, are you sure it's spinning in the same direction?

Theoretically, it should work spun in either direction but sometimes the brushes don't make good contact when spun opposite they way they have been worn in.

 

yep same exact direction heres how it looked

 

Probably not enough belt wrap on the alt pulley and its not enough rpm to charge.It probably does charge if you hold a higher rev for a few seconds though if you want to try that and be sure.

Id still suggest a tensioner though,just because a belt goes on tight..doesnt mean its still that tight underload. Have you seen how much a stock belt flexes when you rev a motor and the tensioner is picking up the slack.Now you removed that function.

 

The belt routing is wrong, you need more belt wrap on the alt pulley.

 

add a tensioner in between the crank and alt pulley...

or move the idler pulley down and put a tensioner where the idler is now.

 

ya, youcant have the idler between the drive and driven pulleys . they only work on the pull side not push the belt just gets loose