| Are fuel pressure regulators troublesome or is it just bad luck? |
Subject: Are fuel pressure regulators troublesome or is it just bad luck? by dan0617 on 2008/6/14 23:27:19 Most of you guys know my setup and it's in my sig so I won't type it again. Been spraying a 150 shot and it pulls hard, feels great. Went to the dyno last Saturday to check things out. Fuel pressure dropped to 30 by 5800 rpms so we shut it down. Air fuel ratio was near 16:1!!!!! (Thank God I didn't melt a piston when I sprayed the nitrous the day before) The dyno guy said the timing being way back and the colder spark plugs are the only thing that saved me. We blocked the return line to test the pump and had plenty of fuel, pressure was 80 and only dropped to 65 by 6200 rpms, and had an air fuel ratio of 10.2:1 so we know the 255 walbro fuel pump is not the problem and the voltage at the pump was checked and is fine. Took the car home. The regulator is a rail mount holley on holley fuel rails (hsr intake), so I turned the pressure all the way down on that regulator, then installed a OBX regulator in line. I don't want to remove the fuel rail and have the hole plugged yet that is why I turned the pressure all the way down and installed a new one. All worked fine for 1 day. Pressure stays up when I rev the car, pressure dropped off when I revved it with the Holley. Had dyno rescheduled for today. This morning the car was flooded terribly. When I removed the vacuum line it was FULL of fuel. Started the car, fuel spraying out the vac port on the regulator. Must be a bad diaphragm. Had to cancel dyno since no regulator available in the state of PA! Ordered a new Aeromotive from Summit, will send OBX back to seller. Are these things known to fail? I thought they were pretty durable. Obviously spring is weak in the sealed Holley unit as I can't get the pressure to turn up over 40 and obviously the diaphragm failed in the OBX. Anyone else had this bad luck? I can't imagine it is something I'm doing wrong, it is pretty cut and dry installing a regulator. Last of all, it somehow made 280 rwhp and 270 rwtq at a very low rpm but it stayed dead flat instead of going up. He said when the fuel issue is ironed out and the air fuel ratio maintains, I should end up with about 325 or so at the rear wheels. Nitrous should put that to about 435 at the wheels. I'll let you all know what it puts down when the reulator problem is fixed. |
