I just recently put a new E85 setup on my car and since I've changed over I'm having a fuel pressure issue under load. I would appreciate your help on this matter.


Fuel System:
Bosh 044 pump inline -6 line welded on to stock pickup 70 micron SS sock ( changed to Walbro 485 same thing) (real Bosch 044 confirmed)

Large bulk heads on pickup 10 gauge wire to chassis ground and wired to Haltech PS1K relay. I've also tried wiring to battery directly no change

-6 SS 90 fittings welded on to stock pickup for feed and return line

1/4 Mocal vent (tested ventilation by unscrewing cap and doing a log no change)

Feed line -6 Teflon coated line to inline -10 micron SS filter brand new to SS hard lines in factory location (changed inline to larger filter no change)

-6 Teflon line to Earl's fuel Y block this is where my SS fuel pressure sensor in mounted (changed fpr sensor no change)

-6 line Teflon coated to feed primary KD rail and secondary KD rail anodized, EV14 1000/2200cc (Teflon lines replaced same thing) (injectors have been re flow tested and cleaned same thing)

Aeromotive FPR new diaphragm a1000 -6 (changed FPR no change)

Return line -6 Teflon coated to hard line -6

Alternator rebuilt high amp with new regulator constant 13.6 Volts under load no change. Tested voltage while under load at relay reads 13.0 volts.

I'm all out of idea's and options...

I had a shop flow test since I know it's a volume /restriction issue and it passed in the rear and middle but not in the engine bay. I had him replace the Teflon lines in the front thinking it was a kink in the line. He also found a fitting that was reduced from hard line to Teflon line in engine bay changed that no change.


Here is a picture of the log middle of the map is under load. Fuel pressure drops to 42psi from 52psi the lowest point at 5,900rpm, 13.6 volts and 13psi manifold pressure. Fuel pressure starts dropping at 5,200 rpm you can also see under normal driving the fuel pressure is erratic.


Not my car but normal fuel pressure on dyno:



Thank you in advance
-Jonathan

 

I had the EXACT issue.

My fuel system is way overkill with a SX fuel pump good for 1300 hp -10 line from tank to injectors.
I had a 100 micron pre pump and 20 micron post pump.
I removed the element from my 20 mic post filter and there was a noticeable increase in pump noise(back to normal)
and it resolved the fuel starvation issue.

For some reason the E85 has a film that develops in the fuel system and clogs the fuel filters.
I cleaned the filters with methanol and noticed some weird stuff settle at the bottom of the container.
Now I'm just running the pre filter and I'll just keep an eye on the injector filters every once in a while.

So even with a pump that runs about 130 Gallons/hr it could not pump the volume through a 20 mic filter.
So for a smaller pump and a 10 mic filter it could be impossible for the pump to do it's job.
As an added note, my filter started to rip holes in the stainless steel element, proving to me that
the pressure between the pump and the filter was extremely high.

I do want to give Johnny at J-Tran Studios props for discovering the issue based on expertise.

My advice, temporally ditch the inline filter completely and let me know if it resolves your issue. It did for me.

Cheers,

Joe

 

Awesome man.. one of the shops pulled the element out and did a test looking at the digital gauge no log he said it went pig rich so they thought they found the issue too small of a inline filter replaced the inline filter to a larger assembly but it was the same thing.

The weird thing the filter JEGS Billet 40 micron was dirty and looked to be strained as you mentioned. I ran the same filter on my Evo X, E85, 400whp no issues but it's not a rotary.

 

Created another post with more information here:
https://www.rx7club.com/single-turbo...e-e85-1059202/

 

You may want to try a much larger inline filter. I using a large fuel lab's 6 micron filter with 2 bosch 044's on E85 with great success.

 

yea i just had the Golan filter that is about 1.5" diameter. it has zero surface area compared to real filters

that one clogged up on me at the track and made my pump super loud. the element had been disfigured and was useless.

i have switched to the earls -8 175 gph filter

also a 40 micron post pump is not a adequate for fuel injection. you will need a 10 micron or smaller

 

Pretty much right on the money. People often complain about injectors being clogged using E85. Well if your using a 40 micron filter and the filter in the injector is 7 microns your can't expect them to not clog. Always go smaller then the filter on the injector and you'll be in front of injector issues more often then not.

 

Please go to this thread and post I've done a few things since: https://www.rx7club.com/single-turbo...e-e85-1059202/

 

Please go to this thread and post I've done a few things since: https://www.rx7club.com/single-turbo...e-e85-1059202/

 

Please go to this thread and post I've done a few things since: https://www.rx7club.com/single-turbo...e-e85-1059202/