The fuel pressure in my 89 Novi 2K SC'd stang has been shooting up to ~90 psi the second that it starts to make boost (~2500rpm). I'm talking less than 1/2 a pound of boost. This is with my fp set at 41 psi line off on my adjustable fpr.
I was under the impression that the FMU was supposed to increase fuel pressure by the ratio the FMU is rated at, which should be 14 psi fuel pressure for every 1psi of boost, since my unit is supposed to be a 14:1. In other words, I thought the fuel pressure should ramp up as boost builds. Example: With my fuel pressure set to 41 psi line off, when the boost hits 1psi I thought the fuel pressure should raise 14 psi, up to ~55 psi. Same with 2lbs of boost, I thought it should raise 28 psi, giving me ~69 psi of fuel pressure. Mine seems to be working like an on/off switch. When the car is at vacuum to 0, the FMU isn't working and the car runs fine. At less than 1/2 lb of boost, the FMU "switches on", and pressure goes straight from 41 psi to 90 psi.
I can tell that the car runs REALLY rich when the fuel pressure shoots up to 90psi. Basically, it runs like crap. It's totally fine til that first tiny bit of boost builds, then the fuel pressure shoots up and the power goes wayyyyy down, car sputters and shoots black smoke out the tail pipes.
I don't think an FMU should be working the way mine does. Can anybody tell me if it is or isn't working right?
I was under the impression that the FMU was supposed to increase fuel pressure by the ratio the FMU is rated at, which should be 14 psi fuel pressure for every 1psi of boost, since my unit is supposed to be a 14:1. In other words, I thought the fuel pressure should ramp up as boost builds. Example: With my fuel pressure set to 41 psi line off, when the boost hits 1psi I thought the fuel pressure should raise 14 psi, up to ~55 psi. Same with 2lbs of boost, I thought it should raise 28 psi, giving me ~69 psi of fuel pressure. Mine seems to be working like an on/off switch. When the car is at vacuum to 0, the FMU isn't working and the car runs fine. At less than 1/2 lb of boost, the FMU "switches on", and pressure goes straight from 41 psi to 90 psi.
I can tell that the car runs REALLY rich when the fuel pressure shoots up to 90psi. Basically, it runs like crap. It's totally fine til that first tiny bit of boost builds, then the fuel pressure shoots up and the power goes wayyyyy down, car sputters and shoots black smoke out the tail pipes.
I don't think an FMU should be working the way mine does. Can anybody tell me if it is or isn't working right?