U/D Pulley Intall Help!!

mustang fanatic · November 7th, 2009, 08:53 PM

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!

Bullitt95 · November 8th, 2009, 09:00 AM

Originally Posted by mustang fanatic

Could I put the stock water pump pulley back on and leave the crank pulley only? Will it run fine that way?

Yes and yes.

mustang fanatic · November 8th, 2009, 01:41 PM

Any idea why the belt is slipping off the back of the new water pump pulley?

Bullitt95 · November 8th, 2009, 03:56 PM

The belt could be too slack.

mustang fanatic · November 8th, 2009, 06:52 PM

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!

Bullitt95 · November 9th, 2009, 04:42 AM

Glad you got it sorted out.

mustang fanatic · November 9th, 2009, 11:40 AM

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!!???

Bullitt95 · November 9th, 2009, 12:48 PM

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).

mustang fanatic · November 9th, 2009, 12:54 PM

Originally Posted by Bullitt95

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?

Bullitt95 · November 9th, 2009, 01:04 PM

Originally Posted by mustang fanatic

Maybe the belt is slipping because it isnt tight enough? So the alternator not charging the battery enough would make it jerky accelerating?

Possibly.

mustang fanatic · November 9th, 2009, 01:12 PM

Originally Posted by Bullitt95

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?

Bullitt95 · November 9th, 2009, 01:48 PM

Doesn't matter which water pump pulley you use as long as the belt is tight.

mustang fanatic · November 9th, 2009, 02:01 PM

Originally Posted by Bullitt95

Doesn't matter which water pump pulley you use as long as the belt is tight.

Should I be fine driving home?

Bullitt95 · November 9th, 2009, 02:18 PM

As long as the belt is tight and isn't slipping, you should be fine.

November 7th, 2009, 08:53 PM	#1
mustang fanatic Hardcore Enthusiast 1994 Mustang Cobra Join Date: Jan 2007 Location: Orange County,CA Posts: 2,139 iTrader: 0 reviews	U/D Pulley Intall Help!! 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! __________________ 1994 Cobra - Bassanni Shorties, Borla Catback, JLT CAI, MSD Cap & Rotor, FRPP Spark Plug Wires Coming soon: FRPP Aluminum Driveshaft, Aluminum Flywheel, and X-pipe

November 8th, 2009, 01:41 PM	#3
mustang fanatic Hardcore Enthusiast 1994 Mustang Cobra Join Date: Jan 2007 Location: Orange County,CA Posts: 2,139 iTrader: 0 reviews	Any idea why the belt is slipping off the back of the new water pump pulley? __________________ 1994 Cobra - Bassanni Shorties, Borla Catback, JLT CAI, MSD Cap & Rotor, FRPP Spark Plug Wires Coming soon: FRPP Aluminum Driveshaft, Aluminum Flywheel, and X-pipe

November 8th, 2009, 06:52 PM	#5
mustang fanatic Hardcore Enthusiast 1994 Mustang Cobra Join Date: Jan 2007 Location: Orange County,CA Posts: 2,139 iTrader: 0 reviews	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! __________________ 1994 Cobra - Bassanni Shorties, Borla Catback, JLT CAI, MSD Cap & Rotor, FRPP Spark Plug Wires Coming soon: FRPP Aluminum Driveshaft, Aluminum Flywheel, and X-pipe

November 9th, 2009, 11:40 AM	#7
mustang fanatic Hardcore Enthusiast 1994 Mustang Cobra Join Date: Jan 2007 Location: Orange County,CA Posts: 2,139 iTrader: 0 reviews	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!!??? __________________ 1994 Cobra - Bassanni Shorties, Borla Catback, JLT CAI, MSD Cap & Rotor, FRPP Spark Plug Wires Coming soon: FRPP Aluminum Driveshaft, Aluminum Flywheel, and X-pipe

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November 8th, 2009, 03:56 PM	#4
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.36 @ 105.0 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,387 iTrader: 0 reviews	The belt could be too slack.

November 9th, 2009, 04:42 AM	#6
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.36 @ 105.0 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,387 iTrader: 0 reviews	Glad you got it sorted out.

November 9th, 2009, 12:48 PM	#8
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.36 @ 105.0 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,387 iTrader: 0 reviews	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).

November 9th, 2009, 01:48 PM	#12
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.36 @ 105.0 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,387 iTrader: 0 reviews	Doesn't matter which water pump pulley you use as long as the belt is tight.

November 9th, 2009, 02:18 PM	#14
Bullitt95 Hardcore Enthusiast 1995 Mustang GT auto 13.36 @ 105.0 Join Date: Apr 2007 Location: Al Ain, UAE Posts: 1,387 iTrader: 0 reviews	As long as the belt is tight and isn't slipping, you should be fine.

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