Trying to track a problem down....

Fuel pressure fluctuates like 2-4 psi at idle with regulator hooked and unhooked. I think it does at higher throttle settings, but is hard to tell. Having low throttle surging issues and rough idle... Shouldn't the pressure be more solid, esp. with the vacuum off the regulator????

 

I could fluctuate but I don't think it should be 4 psi if the engine is idling well and the hose is removed. With the hose removed, I believe it simulates a WOT condition. Why don't you see if it holds the pressure by turning the key on and prime it and watch the gage to see if it drops off quickly? It should hold for a bit more than 10 mins.

 

It will hold after the key shuts off. It is like 40psi with the key on, 36 at idle, ~ 42 at wot, and 70 with return line blocked. Bounces when engine on and at less than near WOT...

 

Sounds a little low to me. Maybe the spring on the diaphragm in the FPR is weak. You might need to change the FPR. Not too difficult. You need torx bits with the center holes punched out

 

Hmm....maybe I will do the pump at the same time just in case. The car gets closer to carburation every day...

Thanks for your help! I will let you know. Any other thoughts?

 

Normal fuel pressure readings for a TPI engine, I don;t see a problem with those numbers. Nothing low about them....

 

Shouldn't it be like 44-45 at idle with the hose off? That was what mine was with stock pump and stock FPR.

 

With my fuel pressure set, my underhood fuel pressure gage checks 36/38 with the key turned on and 40 at idle and after running, My max FP is set at 45PSI for WOT.

 

With the hose off and the car idling, isn't that a WOT setting?