Fuel Pressure regulator

[Puremuscle]

I had to replace an injector on the 92 X. as i was removing the injector rail i noticed a place that appeared to for a vacum line on the regulator, but nothing was attached to it. Anybody have any ideas if a hose should have been attached and if so, where do i need to run one.

 

[JDraper]

Yes, you need a vacuum hose on the FPR. I'm not sure where it originally came from though. I think it's supposed to come off the vacuum tree at the back of the engine, but I'm not 100% sure.

 

[Puremuscle]

Yeah, i found a post that showed a vacuum diagram and it should be connected to the tree. The funny thing is, the truck seems to be running fine. So, is the regulator vac controlled?

 

[Maniak]

Sort of.. With vacuum applied the Fuel pressure is in the mid to low 30's. With no vacuum (like on heavy acceleration) it runs around 42psi. Without it connected you were running higher fuel pressure than normal, but not by much.

I had a FPR die and our FPR was running 60-65psi. That pressure was enough to make it run really rich..

~Mark

 

[Puremuscle]

Thanks for the insite. I hooked the line up and didn't notice any change. I do have another situation. I have an idle issue. There are times when the engine idle is fine and other times it begins to creep higher and higher, to around 1500, for no apparent reson. I guess i should start with codes first, right?