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Discussion Starter · #1 ·
Hi Everyone!

I need help! I just installed the MAC Underdrive Pullies on my 94 mustang cobra. The belt on the water pump pulley is slipping off the back of the pulley. The MAC pulley didnt come with a lip to hold the belt on. Any ideas on how to fix this? Could I put the stock water pump pulley back on and leave the crank pulley only? Will it run fine that way? Thanks for your help!
 

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Discussion Starter · #3 ·
Any idea why the belt is slipping off the back of the new water pump pulley?
 

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Discussion Starter · #5 ·
I figured it out! I had the crank pulley on backward. So it was pulling the belt off toward the engine! Stupid companies and not providing directions with pictures! LOL. Thanks for your help though Bullitt. I really appreciate it!
 

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Discussion Starter · #7 ·
Bullitt I am still having problems!! So yesterday on my test drive everything was fine. But this morning on my way to work in 1st and 2nd gear at low rpms the car was all jerky and almost felt like it wants to stall. I have to shift at about 2400 rpm and it doesnt do it as much. Then if I am in 5th going around 45mph to 50 mph it does it? Then when sitting at a light the voltage gauge flickers back and forth. It doesnt sway much, maybe a few mm to each side. Whats going on here? Any help please!!???
 

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Sounds like the alternator isn't charging the battery properly and when the battery voltage drops at low rpm, it's not able to adequately fire the injectors. Try swapping the stock alternator pulley back on (you'll need a slightly shorter belt).
 

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Discussion Starter · #9 ·
Sounds like the alternator isn't charging the battery properly and when the battery voltage drops at low rpm, it's not able to adequately fire the injectors. Try swapping the stock alternator pulley back on (you'll need a slightly shorter belt).
Its got the stock alternator pulley on it and stock water pump pulley. The only pulley I have changed is the crank pulley. Maybe the belt is slipping because it isnt tight enough? So the alternator not charging the battery enough would make it jerky accelerating?
 

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Discussion Starter · #11 ·
Possibly.
Should I put the MAC water pump pulley on? Or just switch it back to stock and see how it runs?

I have a 40 mile commute back home, will my car be okay to drive that far back?
 
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