[holdcop]

Ive been dealing with a low low side fuel pressure issue for quite some time now thats preventing me from making full power on my upgraded twins (09 335i). I have narrowed it down to being a voltage/amp draw problem with my ekp from arc terminator which is getting replaced. 55ish psi idle, mid 40s at redline and 80+ between. Happens on a 20psi boost base tune, 93 gas, and w/ a walbro 450 (flow tested by PR).

Im curious if there is anything else i should look for other than the ekp once it gets replaced. I have installed a new oe fpr, PR low side fuel line, and will be doing the sensor when it comes in the mail. On another note, would there be an issue replacing the EKP entirely with a relay such as arc terminators test board, or the speedsty "ekp upgrade board?" Considering the tank has a return system, what is stopping me from just using one of these instead of messing around with ekp BS?

Edit: I ran a qr mile pass with the arc terminator ekp bypass relay thingy, (30A relay) and the car made adequate pressure, which is why ekp is suspect. My voltage reg went bad same night, which is tweaking me out enough to be cautious about trying the relay again. Is it possible these are related or just some wild coincidence? The regulator had super worn down probes

[oVeRdOsE.]

on what you're reading the lpfp pressure?


you can test with a 328 EKP too , just to be sure. I ran my 328 stock fuel setup for a while and getting around 400whp no problem (n54 swapped car). I probably could have go higher, my logs were super stable around 60-70psi.

Other item you can check is the fuel pump hoses, mine splitted and I was loosing 20psi, but can ran since I was around 45psi.
The hose going to the vertex valve in the bucket.

[holdcop]

Originally Posted by oVeRdOsE.

on what you're reading the lpfp pressure?


you can test with a 328 EKP too , just to be sure. I ran my 328 stock fuel setup for a while and getting around 400whp no problem (n54 swapped car). I probably could have go higher, my logs were super stable around 60-70psi.

Other item you can check is the fuel pump hoses, mine splitted and I was loosing 20psi, but can ran since I was around 45psi.
The hose going to the vertex valve.

Reading on MHD. I ordered a secondhand ekp to see and have one while i send back the upgraded one. I dont see any leaks under the car, and put in the precision raceworks upgraded line that goes from the FPR to HPFP. are you talking about a hose inside the tank?

[oVeRdOsE.]

Originally Posted by holdcop

Reading on MHD. I ordered a secondhand ekp to see and have one while i send back the upgraded one. I dont see any leaks under the car, and put in the precision raceworks upgraded line that goes from the FPR to HPFP. are you talking about a hose inside the tank?

yeah the hoses inside the tank.


mine splited open , but not enough to get 0 psi.

also I have a 450 on the 335 ekp, I simply added some sticky heatsink and a old GPU fan.

[holdcop]

Originally Posted by oVeRdOsE.

yeah the hoses inside the tank.


mine splited open , but not enough to get 0 psi.

also I have a 450 on the 335 ekp, I simply added some sticky heatsink and a old GPU fan.

Whats going on with the T on the pump? Mine only has a fitting that attaches to a hose going to the FPR

[oVeRdOsE.]

I did this DIY : https://bmw135iblog.wordpress.com/20...-pump-upgrade/