gabbett1 Posted April 13, 2006 Report Share Posted April 13, 2006 So I just recently built my engine up to a 403 and changed my ProCharger to push 13 psi to it, put 60 lb injectors in and I cannot keep fuel pressure to it when I floor it. It instantly jumps up to 80 lbs and in less than a second it drops to 30 lbs. What did all you big horsepower guys do to keep your fuel pressure up to snuff? Oh, and the regulater is screwed in all the way, so it isn't in need of adjustment. Link to comment Share on other sites More sharing options...
BenKey Posted April 13, 2006 Report Share Posted April 13, 2006 What have you done to your fuel pump, anything? Link to comment Share on other sites More sharing options...
gabbett1 Posted April 13, 2006 Author Report Share Posted April 13, 2006 The fuel pump in the tank is stock, and we put in a new inline pump. Link to comment Share on other sites More sharing options...
BenKey Posted April 13, 2006 Report Share Posted April 13, 2006 What is your idle pressure - curious? Link to comment Share on other sites More sharing options...
gabbett1 Posted April 13, 2006 Author Report Share Posted April 13, 2006 48 lbs round about Link to comment Share on other sites More sharing options...
gabbett1 Posted April 13, 2006 Author Report Share Posted April 13, 2006 Is it possible that the pump in the tank went bad? Link to comment Share on other sites More sharing options...
FuelSlut Posted April 13, 2006 Report Share Posted April 13, 2006 join the club... good luck with this man, i have had somewhat the same issue... but not as dramatic, and i kinda "cured" it... still not perfect or the way it should be, but def. not perfect... i have replaced the in-tank pump several times (all aftermarket) Link to comment Share on other sites More sharing options...
BenKey Posted April 13, 2006 Report Share Posted April 13, 2006 48 lbs round about <{POST_SNAPBACK}> Even that is low. Should be around 58psi. I'm not an expert in this area, or any other for that matter, but I would guess that you're close to needing 2 pumps with the larger cubes and 13lbs of boost. The stock pump and an inline may not cut it. Have you logged your WOT runs and checked your ltrims, or air fuel? I would also assume that you changed your tune quite a bit? Link to comment Share on other sites More sharing options...
rgp6373 Posted April 13, 2006 Report Share Posted April 13, 2006 i had that problem when i first got my radix turned out to be the regulator which has 2 o-rings the second is small and easy to loose was told it happens a lot Link to comment Share on other sites More sharing options...
Bowtie70SS Posted April 13, 2006 Report Share Posted April 13, 2006 Are you running a FMU? Isit possible that you have the wrong reference(vacuum hose) going to it? Just an idea. Dave Link to comment Share on other sites More sharing options...
gabbett1 Posted April 13, 2006 Author Report Share Posted April 13, 2006 48 lbs round about <{POST_SNAPBACK}> Even that is low. Should be around 58psi. I'm not an expert in this area, or any other for that matter, but I would guess that you're close to needing 2 pumps with the larger cubes and 13lbs of boost. The stock pump and an inline may not cut it. Have you logged your WOT runs and checked your ltrims, or air fuel? I would also assume that you changed your tune quite a bit? <{POST_SNAPBACK}> The idol psi will be fixed when we get the tuner to finish the tune. I had a guy get the tune close so that there wouldn't be much to adjust on it, and the guy got it very close. But to answer your question, no I haven't logged any WOT runs cause you cannot step on it for more than, and I'm not joking, 1.5 seconds. The fuel pressure drops off so fast it's rediculous. And to answer someone elses question, yes I am running an FMU. If you read my first post, I mentioned that it is screwed all the way in. I did check the hose and it is connected properly. Link to comment Share on other sites More sharing options...
gabbett1 Posted April 13, 2006 Author Report Share Posted April 13, 2006 What would be the best solution... -a performance pump in the tank that has a voltage booster to it to put out more flow once the truck goes into boost... or -two performance pumps that are supplying one line like this: Example Link to comment Share on other sites More sharing options...
Bowtie70SS Posted April 13, 2006 Report Share Posted April 13, 2006 I am not 100% sure about this, since I have never used a FMU, but....Could the FMU be stepping the pressure up, and the regulator on the fuel rail be pulling it back to what it "thinks" it should be? I know you already said you have it hooked up correctly, but I'm trying to understand how it works too! On the radix the fuel pressure regulator gets boost instead of vacuum when it's under pressure. I'd sure be glad to hear how you fix it once you figure it out. Dave Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted April 13, 2006 Report Share Posted April 13, 2006 Twin 255lph pumps with a hobbs switch on one (at about 7psi) Link to comment Share on other sites More sharing options...
BenKey Posted April 14, 2006 Report Share Posted April 14, 2006 Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.