I recently took my car and had it tuned by an SCT tuner, when I got the car back it ran great no problems, now all of a sudden my fuel pressure at idle is jumping around from 25-30psi, when I remove the vac line to the regulator the needle on the gauge sits dead on 25psi and won't move. I replaced the fuel filter today thinking that might be the problem but no luck. I do not think its the pump cause when I turn the key I hear the pump prime. My current fuel set up is 39lb ev6 injectors, 255lph fuel pump, and a BBK fuel pressure regulator. I also called the tuner and he said he set the Fuel pressure at 39psi with the vac off. Any help would be great thanks.Supercharged Mustang having fuel pressure issues
- Thread starter Brsmustng93
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I recently took my car and had it tuned by an SCT tuner, when I got the car back it ran great no problems, now all of a sudden my fuel pressure at idle is jumping around from 25-30psi, when I remove the vac line to the regulator the needle on the gauge sits dead on 25psi and won't move. I replaced the fuel filter today thinking that might be the problem but no luck. I do not think its the pump cause when I turn the key I hear the pump prime. My current fuel set up is 39lb ev6 injectors, 255lph fuel pump, and a BBK fuel pressure regulator. I also called the tuner and he said he set the Fuel pressure at 39psi with the vac off. Any help would be great thanks.-
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I would suggest taking it to the tuner so he can look over the car and take another look at the tune.
I myself have had problems with some tuners 1. I took my car in to get tuned and it had a hiccup when I got it back. Ended up getting new coil packs and problem solved. 2. Fixed the vaccum lines and the car started shutting off, had to rewrite the bottom end of the tune.
I myself have had problems with some tuners 1. I took my car in to get tuned and it had a hiccup when I got it back. Ended up getting new coil packs and problem solved. 2. Fixed the vaccum lines and the car started shutting off, had to rewrite the bottom end of the tune.
maybe the reg is gone bad. How does it run with FP being that low it should be running rough also. maybe the gauge is on its way out. if you could find a way to block the fuel return and then look at the FP if it spikes way up that should help rule out the pump. Have you run over any thing that could of hit the fuel lines and crimped one? check to make sure that the lines back at the tank the plastic one are not crimped any where also up at the front where the lines go to the rails.
This was my first line of thinking as well. Fuel line crimping pliers can help with blocking the return line to see if pressure spikes afterwards.
If the car runs mint, it would not be the first time a gauge went wonky. Having a diagnostic FP gauge (which can be loaned out from some parts stores) can help determine that.
Good luck.
ej95cobra
Member
Mine sits at 28-30 PSI at idle and is actually running rich. My fuel pressure with vac off is at 40 psi. I have 36# injectors and a 255lph fuel pump.
Again, do you know that your gauge is working properly on a consistant basis. Your car should have been idling like crap at 20 PSI.
Have you tried any of the suggestions made already? Have you pulled codes - you should have an A/F code if your FP is moving around that much.
LordMustangGT
Member
I just had a buddy of mine have he pump go out slowly. It still ran but fuel presure was low enough that above 3 grand it just felt like it had no power. Replaced the pump with a 255lph and all problems fixed,.... This was a pretty much stock car too.
