I bought 2 of these liquid filled 1-100 psi. 1 1/2" fuel pressure guages since my other one has a crack in it. it's set at 50 psi. And its installed in my aeromotive fpr. I tried both of these and both are reading 30 psi.? What's the deal, do i need to adjust this some how? I am datalogging and i'm getting plenty of fuel. help thanks

 

used a external fuel pressure tester. and it reads 22 psi at idle too. so the guages are right. the car is idleing fine, it has a new walbro pump, new filters, and i opened up the fpr and the diaphram looks ok and their is no debris in their. Does anyone know why it's reading that low? i now turned it up to 50, and it is getting way too much fuel. what else could be the problem?

 

maybe the guage reads after the diaphram off of the return line

 

I wish that was it. We hooked up a dialed in fuel pressure tester to the fuel filter and it is reading the same. What's funny is that the car ran last friday with the pressure set at 25 at idle and I'm smoking still like i am getting too much fuel and im running low 11's at 16 pounds of boost. Could i have a leaky injector, can that cause a low pressure reading? This is wierd, you would think the car wouldn't run at 25 psi of fuel pressure. My pressure does rise to 33 when i disconnect vaccuum so i would think the regulator is still functioning. I am running a FAST sequential stand alone, and running 1000cc msd injectors. Has anyone ran into this problem?

 

you are loosing pressure somewhere make sure that you have no leaking fuel and that all of your injectors are working properly

also, what size injectors do you have and what duty cycle are you running at and what is your setup?

 

no leaking fuel, they are 1000 cc msd injectors, which only run about 89% duty cycle at peak torque, good power balance across. the set up is a built h22 motor, stock cams, turbonetics 62-1 p-trim 81ar. air to liquid setup, crane hi-6 ignition, and FAST stand alone w/ wideband. Peak torque at 7000 rpm's and peak hp at 7600. 721 whp, 589 tq.

 

well with those large of injectors....I would have to say that you are tuned rich and that you are overworking your injectors especially at 16psi (I don't see a reason to be pumping 890cc at WOT for 16psi).....it seems as though you know what you are doing if you have that much power being put down. This is just what I think is going on....I would suggest posting this in FI because those guyz would have wayy more experience with large injectors seeing as though I am a N/A *****

maybe one of the pindles are not closing all of the way and letting the fuel leak and loose pressure seeing as though they are soo large

what size fuel pump are you using....you can have a low pressure but if the pump is large enough it will keep the pressure there in almost any circumstance

 

I think I found the problem. My old guage was broken when my inline pump took a dump on me. It was a Venom 340 lph. It was whining loud and hot to the touch. So, I bypassed that and have been using my Walbro 255 lph hp. Since the Venom is dead, the Walbro was pushing through the Venom pump and only putting out 25 instead of the original 50. That explains my car choking at 6500 rpm's at the track.