'88 Itasca Fuel Pressure Regulator
There was another long thread concerning the identification of a fuel pressure regulator in a picture. I had to replace this on my rig last week so thought I would post a new thread with what I found out.
My regulator was located in the oblong frame cut-out behind the R/R set of duals and behind the generator. There was a fresh staining of the paint on the frame rail that caught my eye so ran the engine, but could not find a leak. I then drove the rig aways and then crawled under and there was the leak.
This regulator has an adjusting screw and locknut visible from the outside of the frame rail. There is a vent hole in the body of the valve right at the outer edge of the locknut and this is where the gas was coming from. The rubber diaphram must have a hole in it. The hole is to allow air to vent when the rubber diaphram moves, do not plug it.
GM no longer supplies the valve so after researching this valve I found a replacement at Pep Boys for less than $40. A local speed shop should also have it.
The Regulator is a Holley #12-804, 1-4 psi.
This valve has ports for two outlet fuel lines so you will also need a 3/8" pipe plug to seal one port.
This regulator drops the pressure from the electric fuel pump located in the fuel tank so it is necessary. There is a mechanical fuel pump on the engine also.
Wasn't the easiest job as there is very little room to work between the frame rail and the fuel tank. Once you break the line from the tank loose you can take the bolt in the regulator mounting bracket out of the frame and pull the reg. out of the frame a little ways.
We went on a short trip after I installed this and hit a couple of steep grades and the engine ran just fine with the new regulator installed.