12 valve: added fuel psi, lost serious power!

[sltlytwkd]

The 12v in my sig. I had the stock OFV and full cuts in it with the afc backed all the way off to control the smoke. I randomly decided to put the stock 131 dv's back in, and I removed the stock OFV and replaced it with a high speed check valve. I now have 58psi of fuel instead of the stock 20psi.... and zero throttle response, barely idles. I put the full cuts back in, starts and idles great, but still zero throttle response. The truck will barely move until 10psi boost, then burn Tire like rubber is free. Lol. AFC right? I tried it full forward, nothing. I tried a gutted AFC I had laying around, nothing! Why did adding fuel psi totally mess everything up!?

 

[95cummins5.9]

Is the woodruff key on the shutoff solenoid shaft?

 

[Tx tyre fryer]

Nothing to do with fuel pressure, but when I went from 191s back to 131s I had to tighten up my governor springs a couple clicks and it ran much better.

 

[Teamfreeman04]

Could be timing...maybe putting the fire out with the added fuel

 

[sltlytwkd]

Is the woodruff key on the shutoff solenoid shaft?

I removed the shutoff solenoid and am holding it forward with a spring. Just to make sure the solenoid wasn't getting lazy and causing the problem.

 

[sltlytwkd]

Could be timing...maybe putting the fire out with the added fuel

If I remember right, I had set timing around 18° so it would start easier for the winter. You think timing would change that extremely?

 

[sltlytwkd]

Nothing to do with fuel pressure, but when I went from 191s back to 131s I had to tighten up my governor springs a couple clicks and it ran much better.

How do you go about doing that? Sorry never messed with gov springs yet...

 

[Tx tyre fryer]

How do you go about doing that? Sorry never messed with gov springs yet...

Just pull off the afc and have someone rotate the engine as you watch for the springs. There's 2 sets. Tighten the nut on the top a couple clicks each with a screwdriver.

May not want to do this if the springs are still stock

 

[CorneliusRox]

How do you go about doing that? Sorry never messed with gov springs yet...

The easiest way is to remove the stamped cover on the side of the pump (normally covered by the FSS's valve). Then there's a nut you tighten, then bar the engine, then tighten the other nut. (make sure the depth is the same for both sides).

Alternatively, you could pull the AFC and get to it through there. I had to build a special tool to do it this way on mine (for quicker adjustments). Basically a long t-style handle with a screwdriver end with the middle cut.

NOTE: I'm using other people's pictures via Google.

 

[Tx tyre fryer]

Have you put the stock ofv back on yet to make sure that's your problem?

 

[sltlytwkd]

Have you put the stock ofv back on yet to make sure that's your problem?

That's the only thing I did not do yet. Just ran out of time

 

[sltlytwkd]

So I tried tightening the governor springs 2 clicks, which brought them from .0550" ish to .0850" ish. Then it would barely start even playing with the throttle. So I put them back to normal and took the 2 shims out of my check valve and it brought the fuel pressure to exactly 50 psi. I would go lower to mock stock psi but I have to find a different spring. Still no luck. The truck barely moves itself until 10 psi boost yet.... Is it normal to have a "hard" spot in the throttle that goes away as the fuel/boost comes on?

 

[jasonc]

Are you sure the AFC is moving, you said you gutted it and tried. That's exactly how the peddle feels when its not moving.