No boost =( need help

K

Kris

Forum Member
Welll, I put a new, nearly complete 03 motor for my 01 Lightning. I had to reuse the tps, egr, boost bypass solonoid, and the injectors. Everything else is new.

The problem is, I'm not getting any boost now. We looked over everything and its all hooked up. My buddy tested the boost bypass solonoid, said something like 77.8 ohms.

All the vacuum lines look to be hooked up correctly. I used a pressure gauge to see if the boost gauge is working and its correct. At wot the gauge moves to 0, doesn't get a spec of boost.

We ran a scan tool on it. The ecu only shows there is 1 rear O2 sensor, and its reading 0%. A tech said if the rear O2s aren't working then the ecu "turns off" the supercharger. Is this right?

The only mods it has are, superchip, 4lb lower, long tubes/ offroad Y pipe, cone filter. As far as I know, the ecu hasn't been reprogrammed with a tuner, but I'm not sure.

Anyone have any ideas what to look for? I want boost back. It made about 12ish pounds of boost with the old motor. Now I have nothing. We reset all the codes and still nothing. I wonder if the new supercharger is bad or the solonoid is bad.

My buddy nate is a tech at brondes and he's even stumped on this one. If someone could help me out, it'd be much appreciated. The truck is awaiting a tune once this is fixed.

Thanks.
 
You cant turn off a blower. It sounds to me that either the blower is bad, or the bypass is stuck open.

i would pull the blower and spin it by hand. Do the rotors move? If not there is internal damage to the blower either the coupler or gears. if they do check the bypass. stuck open or broken?

Does the supercharger make any weird noises?
 
You can hear the blower whine, but it makes no boost. The bypass valve is working right, but somehow there isn't any boost being made. The only weird noise it nakes is I can hear the ball bearings in the supercharger but when I pull some vacuum line off and cap other, that noise either gets louder or quieter, but the same result on boost.

Another tech said if the ecu doesn't read the rear O2 sensors working, it won't allow any boost to be made. Not sure how that works, just throwing options out.
 
If the tech said it wont make boost that means its holding your bypass open.

you shouldn't hear ANYTHING from a blower at idle. This is the lightning M112 blower right?

You either have a busted blower or that bypass is open.

Pull the line off the bypass, plug it, and take an EASY ride. Roll into it ONCE and watch boost. If you have boost with the bypass unhooked then you have to figure out the O2 sensor issue. otherwise blower is bad.


good luck.
 
We bypassed the solenoid and it still made no boost but I don't think we've bypassed the valve itself. so I need to bypass the bypass valve? Where will excess boost go?
 
then check the Bypass arm/connection on the side of the blower.


mp122bypass.jpg


Ford-F-150-F150-SVT-Lightning-Eaton-Supercharger-Intake-for-sale_320495034071.jpg


Its the black thing in the second pic. make sure its connected/not screwed up. that black thing is the vacuum actuated "pot" that pushes/pulls on the bypass valve actuator arm.
 
Kris said:
We bypassed the solenoid and it still made no boost but I don't think we've bypassed the valve itself. so I need to bypass the bypass valve? Where will excess boost go?
Click to expand...

If you bypassed the solenoid but left the valve hooked up to something like vacuum it would be pulled open under vac but closed under 0 vac or boost, when vacuum becomes present again it will open.

excess boost goes back into the vacuum side of the blower, since its all metered air it dosent cause running issues (lean outs/stalling).
 
Kris said:
Sounds to me like I'm gonna have to pull the blower off of the motor, right? Ugghh... lol.
Click to expand...

you shouldn't have to, the actuator is mounted outside the blower on the driver side, make sure it isn't cracked or leaking

see if you can manually move the rod coming out of the actuator
 
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smooth said:
you shouldn't have to, the actuator is mounted outside the blower, make sure it isn't cracked or leaking
Click to expand...

and make sure its connected to the arm for the bypass valve. If the valve is not connected to the actuator then the actuator will be constantly open. Open = NO boost.
 
Yea I've checked that. The arm moves like it suppose to, but I can't see the flap on the back of the blower to see if its actually open. Its too close to the firewall.
 
So are you trying to say that no boost is reading on the gauge? Im slightly confused because this is a roots blower and its pretty much goin to make boost if the belt is hooked up. Have you drove the truck? Its really not going to do much without load.
 
Yupp, been driving it. I hooked up a gauge an it also showed that I'm not mnaking any boost. Yesterday, I checked all of the vacuum lines for leaks, checked the plunger to see if its working right, and also did that bypass delete trick and still the same result. Pretty sure the supercharger is bad but idk how. I'm gonna throw my old supercharger on and see if there's a difference.
 
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