Last week I had the time to reinstall the Walbro fuel pump. I'm still using the stock injectors btw. With the stock Vortech fmu still in place my pressure read 32psi @ idle which is the same as stock. I then switched out the recalibration disk and now my pressure is at 40psi @ idle. When I'm doing normal driving I'd see it go to 42psi. After a hwy drive I noticed that the pressure dropped down to 38psi @ idle and then later on back down to 32psi. What's up with that? Starting up first thing in the morning I'd see 40psi.
Now when I reinstalled the Walbro I just reused the original hose clamp instead of the screwdriver/band clamp. Would that be the cause of the problem?

 

where are you taking readings, before or after the fmu.

 

Good question. I can't remember how I positioned the pressure sensor so I'll have to take a look and come back here later.

 

you probably have it after the fmu which is the correct place, but you should also test from the walbro itself and see what readings your getting. im not positive but i though it wasnt possible to change the disk on the stock vortech fmu's to run correctly maybe thats the problem.

 

If you have the sender in line, it may give faulty readings. try adjusting it so the fuel has to make a corner.

 

Ok, thanks! I do plan to take out the Vortech fmu as soon as a free weekend comes up anyways so I'll put up with the weird gauge readings a little while longer. The pressure sensor will be mounted on the Aeromotive fpr.