Ok, let me apologize if this is the wrong thread, but I’m at my wits end. So 6 months ago I was taking a trip back home from work, it was a 5hr trip and when I got 30 mins from my house it fell flat on its face and started missing. So I changed spark plugs, then changed coil pack on cylinder 4, then come to find out my 2 month old ID1050x wasn’t working properly. So I changed that out, now it idles fine and is driveable, however I can’t build boost. So I pulled my fuel pump and it was full of some black sh*t. I cleaned the filter and checked the pump it was all good, Still not fixed. So I just changed out my fuel rail and put on a new Fuel Pressure regulator with a pressure gauge. I got everything adjusted and checked for leaks and everything was fine. Adjusted my pressure to 43psi at idle yet it still misses when you give it about 1/4+ throttle. But, once you shut off the car I immediately lose fuel pressure, so I know there’s a back pressure issue somewhere but I have no leaks and I’m at my wits end now trying to figure this out. Any and all suggestions and experiences would be greatly appreciated thank you.

 

Your fuel pressure should maintain for a little while after you shut off the engine. The fuel pump has a check valve that keeps it pressurized. The fuel pressure regulator should be only dumping off pressure to the return line if it is above your set value. Your injectors could also be leaking which would cause a loss of fuel but if this was the case (and you were dumping fuel into the intake manifold) it would foul the crap out of the plugs at your next start and start up really rough (this was happening to my honda).

You need to figure out first where your fuel is going. Pinch off the lines on at a time to trouble-shoot it. You need to watch your pressure gauge.

 

Ok, so I’m assuming I’ll just have to Two Step really quick to watch the pressure under boost and be sure it increases correctly for however many lbs it builds? Only issue is it leans out so quick under any boost I don’t wanna knock the hell out of my engine. It has also been starting up a little rough but I thought that was just due to some idiot (aka me) having ethanol in it and temps being in the high 30’s/low 40’s. So that makes me think it is an injector issue as well thanks for the insight.

 

Look into the defective fuel pump relay that was a problem with the X's. It could be your problem.

 

Already checked the relay and swapped it with my high beam relay just in case. Luckily the Evo X Final Edition comes with the slightly more reliable Panasonic Relays.

 

The what... no.

Just drive around and get some slight positive pressure that is way more controllable than that.

Check your venturi, I bet it's clogged.

 

Why is there all this black crap in the pump housing? It should be cleaner than that.

 

You’re guess is as good as mine tank itself way completely clean and I just had the pump housing apart 2 months prior and it was clean then my best guess is a bad batch of fuel

 

only reason I suggested the two step is because my fuel pressure gauge is located in my engine bay, and I have a brand new fuel rail and FPR installed on it

 

I assume that black stuff made it past all my filters and got into an injector or two and was causing me issues I added seafoam a week ago and today is the 3rd time I’ve taken the car out to test things out and it ran like a top...until my FPR started to leak at one of the fittings but easy fix, thanks for the tips and help guys

 

So to clarify I replaced almost my entire fuel system and the car ran fine for about 20mins of idle, afterwards tho the misfire started occurring again. Unplugged an injector one at a time and it continually got worse. After more thought pulled the valve cover and checked Timing and it has jumped. If you get an odd crackling/backfire and AFR’s don’t get too out of wack during gradual and/or more throttle then pull the valve cover and check timing.