Those of you that installed dual fuel pumps, did your wot fuel pressure remain around 50 or did it increase?

I dropped in dual gt pumps(255) in a setup like Huitt has in a thread on here. Except now my wot fuel pressure is a solid 70! Jdm says I should still be around 50, but I'm not...

 

Fuel pressure regulator on the rail? Or wired up wrong the computer should control it

 

Well I sit perfectly at 38-40 during idle or part throttle. Soon as it sees boost jumps to 70 and stays there. It's also making me run pretty rich. I don't have my computer with me to look at old datalogs and see what my fuel pressure was before the pumps.

I was having issues running rich wot before the pump install, just figured it was weak coils or needed new plugs so I never checked fuel pressure. Shouldn't I be throwing a p0191 or similar with my fuel pressure at 70?

 

I had the battery disconnected and pulled the pump fuse, I know the pcm has to relearn these new pumps.

Did a few more runs, same story. Pressure is at 70 and it runs quite richer than normal.

 

running dual fuel pump modules right? Might be a tuning issue also. I think twinscrewd had troyer change something in the tune when his was done by them. If not try taking the fuel pressure regulator and having it see only vaccum and not boost. Mine runs a little richer when it sees boost like it does right now.

 

thats normal, whenever the manifold vacuum drops the rail pressure goes to max.

 

Im going to have my laptop this weekend to look at some old logs of fuel pressure before the pump install to compare.

Jdm is saying I should not be seeing more than 50 at wot conditions since the computer should be regulating the pump voltage to maintain that 50. But like I said I'm pretty sure this high pressure issue started before I put the new pumps in. I won't be able to verify that until Friday though.

Is there anything that can shut down during wot that would cause the pumps to run at max output when they shouldn't be?

 

It looks like the a/f gets richer and richer as boost increases during a wot 3rd gear pull. Starts at roughly 11.6 near 3k rpms, and continually richens to lower 10's as it nears 5k rpms.

During this time the frps reads a constant 70ish even though it continues to richen.

 

Sounds like maybe the fuel pressure regulator is junk. Take the vaccum hose off of it and see if any fuel comes out.

 

Your talking about the fuel pressure sensor on the rail right?

I disconnected the vac line earlier while watching my x3 read the pressure. No fuel comes out, it is working though because when I disconnect the vac line the pressure drops to lower 30's for a split second. When I cmreconnect the vac hose the pressure spikes into the mid 40's for a split second. With the vac hose unplugged, pressure still remains around 38-40 at idle.
I relocated my wideband sensor from the driver side to the passenger side. Had the same a/f as I described before.

Also, will I get different wot a/f ratios when being in first, second, and third gear? Due to engine load? It seems to run a more normal a/f in second gear, hit third and it starts going rich.

 

Just did a wot run first thru third gear. First and second gear pull pretty strong with an a/f in the upper 12's, soon as it hits third gear it feels like it doesn't want to go anywhere. Major lack of power and it runs pig rich. Maybe I do still have weak coils or plugs fouled up some

 

that sounds like the fuel tables are wrong for the tune.

 

Hard to accurately view the data without my laptop, but I was reviewing the 3rd gear full throttle rpm that I logged. The rpm appears to jump up and down even though I'm running it wide open. It may drop up to 40 rpm instantly then jump back up. Most rpm drops were less than that, but I did see a 40rpm drop at one point. Again, pedal is on the floor. Seems like a miss occurring if I didn't know better. 1st gear doesn't do it, can't remember if second gear did it much, but third gears its horrible. Could also be the extremely rich a/f bogging it down at instances I suppose?

 

I don't believe it could be the tune because I didn't use to have this problem. Also seems like its an issue that occurs under the load of 3rd gear since first and second gear have much leaner a/f ratios and are consistent with each other.

Since first and second gear seem to run ok wot with fuel pressure at 70, I think the 3rd gear rich problem is irrelevant of my pressure being high. Otherwise first and second would be just as rich. That and the fact my pressure is very stable at 70, wot.

Idk though, this is my first boosted vehicle so its been/is a major learning experience!

 

Send data logs to jdm and get their opinion