Low fuel pressure/won't start

Alright guys,

I got a 2012 MS3 with full bolt ons. Lately it has quit starting due to low fuel pressure. I swapped hpfp's, the relief valve, and the sensor. I was reading correct pressures between 51-70 psi with the key on and engine off so I know my in tank fuel pump is good. Car is not spitting out any codes and I'm starting to feel lost.

 

How do you know the starting issue has to do with low fuel pressure?

 

There is a ground wire that`s on the driver`s side of the valve cover that will cause the car to not start that gets missed ALL the time. It`s wee tiny, and even the most experienced of the bunch have missed it at times. Worth at least a look.

 

Also possible that the ballast resistor on the frame rail is bad or unplugged for some reason. Those were my exact symptoms after helping with a motor swap for a friend, and he forgot to plug it back in.

 

when I crank the car, the fuel pressure is only going up to 100psi.

yea, ive double checked all the wiring. i didnt forget it

 

100psi Makes me lean towards your HPFP solenoid (Spill Valve) being bad, stuck, unplugged or installed incorrectly. Have you ran E85 in the passed? That could gum it up.

You stated earlier that you installed a new HPFP, are you talking about just the internals or the entire housing?



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If you do need to clean it the recommended way is with (H) VM and P Naphtha Quart by Klean-Strip Link: http://a.co/hE4NBTW and lube it with Red Line 60103 SI-1 Fuel System Cleaner by Red Line Oil Link: http://a.co/3ZHWDRG. Might was well clean the whole unit and take it all apart. Let it soak then scrub it clean and lube with redline before re-assmble.

 

I cleaned my original HPFP, then replaced the whole housing after no change in results

 

Have you checked the resistor? And the ground?

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Which sensor swapped? I'm having the exact same issue after head gasket replacement, which I did myself.
I know all plugs are in snugly and all ground wires are where they should be.

Aye don't fucking know anymore.

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I checked mine according to the service manual, and the resistance reads about 1.1 to 1.2 ohms. Which is about 3 times over what it should be. I read in another thread of a guy that just bridged that resistor plug for testing.... Tried that too with no luck.




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Figured it out over the weekend! The cam position sensor was the cause
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I was referring to the fuel pressure sensor, but since you did a head gasket, did you double triple check your timing?