Currently in the process of working out all the bugs on my new motor so I can take it for a drive to seat the rings and start breaking everything in, but one problem is really holding me up. I'm getting a low fuel pressure code (P0148) and I've went through 2 brand new sets of plugs due to fuel fouling. I did a data log and at various RPMS it is only reading a steady 25 psi. I have a return fuel system and the mechanical gauge on my regulator is ready a lot more than that when revving. The car is on a base tune currently from a very reputable shop, but very stumbly when revving. I had a cheap ebay frps on the rail and I'm starting to think that was my problem. No fuel smell in the vacuum line but a strong smell of fuel in the oil along with all 8 fuel fouled plugs. I have since replaced all 8 plugs....again (ngk tr6), changed the oil with new break in oil and changed the frps with a motorcraft one. I'm redescent to start it again because I'm sick of going through plugs. would this be a sign of the cheap frps not functioning properly?? Any help is appreciated thank you.
P0148 fuel fouling spark plugs
- Thread starter Brad D
- Start date
What is the regulator set to without vacuum? Have you sent the datalog to the tuner? It sounds like they need to do some tweaking.
Regulator set to 43 with no vacuum, I did send a data log after the new tune he sent me with 30% less fuel and from the rail sensor it was only reading 25 psi from idle to 4000 rpm
I guess I could see how the FRPS would cause the issue. If the ECU thinks fuel pressure is low then it will keep the injectors open longer to make up for it. I don't remember if there's a way to get the stock ECU to ignore the FRPS. If there is you could have him set that up and then if the FRPS is the issue A/F should come back.
I'm really hoping that the cheap sensor I had on there was just bad, I have since replaced it with a motorcraft one, but don't want to start it and junk another set of plugs. My best case scenario is the sensor was bad and the new one fixed it, but i will let him figure it out. I talked to him and he is stumped with the over the phone fixes. It will be nice to get some closure anyway on what the issue actually is instead of just throwing parts at it. I was just hoping someone on the forum might have had the same thing happen.
Turn the key on and watch the pressure drop reading. You shouldn't need to start it to get a good reading.
Could you go into a little more detail please? Thats what I've been trying to figure out how to do, Check rail pressure from the sensor with the engine off and key on. Thank you.
FWIW had a FRPS shit the bed idling with a full Fore return system. Pulled in for an inspection and car died. New sensor fixed it. No idea why it went, no issues since years later.
It's been a bit since I've used an FRPS, but when you turn the key on and the pumps prime it should have a pressure reading. Just watch the PID in your datalog. The Pressure Drop Across Injectors (IIRC) should jump up to around 40.
Problem fixed, Did a data log and the cheap frps was only reading 20 psi in the rails when it was actually 48. The new motorcraft sensor I have in there now is reading the correct pressure. It was dumping 50% more fuel to compensate for the mis reading on the cheap frps and flooding it.
glad it was just that.
This is why I just pony up for motorcraft at this point, I don't have the time or patience to chase problems trying to save a couple bucks
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