Weird deal. Broke a belt on my Roush (2004 F150), replaced it. All good now but zero Boost...I mean no whining noise, no boost. The supercharger snout pulley seems to turn fine (with a bit of resistance as it should), all vacuum hoses are all in the right spots and hooked up. I am guessing the butterfly assembly on the Boost Bypass (Black Round canister thing) is stuck open within the manifold? Just a guess.

This truck has already the 6PSI unlock with all the Roush Black Box stuff removed (see thread in this site).

My truck runs like it has no Super Charger. All the pulleys and tensioner are fine.

Have any of you experienced this? It just happened.

 

Just a thought...maybe you broke something when you beat on it with a socket and hammer?

 

sorry that just cracked me up.

 

Did you keep the 64" belt? I'm wondering if it it's not tight enough to spin the blower under load? Spins it at idle thus making you think it's ok. But when the blower has a load on it it's just slipping.

 

Yes, I have the 64" belt on now. It seems plenty tight. I am thinking the linkage on the bypass is stuck and not closing the butterfly in the manifold to create boost?

As far as the hammer goes...seriously it was 2 taps with a socket over the pulley hub to re-set the pulley on the upper shaft and get it aligned. The first time it was installed it was aligned with the stock lightning pulley. Maybe it was never fully seated on the shaft. It didn't come loose I can tell you that. It was tight and I tapped it on a bit.

Prior to "tapping" the pulley on the charger was NOT producing boost.

Thanks

 

Ok. In that case I would check to make sure the plug is tight to the bypass. If you don't have a check engine light for the IMRC then it is likely plugged in. I'm curious why the arm would be stuck. I wonder if it's stuck or of the bypass actuator has failed?

Some good info in this thread https://www.f150online.com/forums/showthread.php?t=413034&styleid=15

 

I inspected the Bypass actuator and it seems the diaphragm is bad. It would not hold any pressure. I bought my kit used so I am suspecting it has allowed boost to escape under WOT since I had it. Now it is completely shot. I bought a new one on Ebay today. I am fairly certain my problem will be solved. I had already done the Bypass vacuum mods so my actuator runs off the vacuum from the fuel rail. I eliminated the Black box and solenoid.