Originally Posted by Mackhack

I'll check on mine too. I didn't have this stutter before the recall repair. Can we exclude a pinched hose?

Originally Posted by jmb614

On my car, it was bad enough the dealer had caused an Evap leak post tank swap, but then after I got it back from the second round of repairs it appears they simply went into STAR and turned off monitoring of the EVAP system.

With that said I have no issues with lean pulls, though I do run methanol. Even then I will see 10.5 AFR, no way meth is adding 1.5 points according to all the logging I have done prior to the tank swap.

Originally Posted by jmb614

On my car, it was bad enough the dealer had caused an Evap leak post tank swap, but then after I got it back from the second round of repairs it appears they simply went into STAR and turned off monitoring of the EVAP system.

With that said I have no issues with lean pulls, though I do run methanol. Even then I will see 10.5 AFR, no way meth is adding 1.5 points according to all the logging I have done prior to the tank swap.

Originally Posted by BigVic

Ok Fellas, I have a big question for all that went through these new pumps.

Have any of you tested your fuel pressure under load after you replaced with the new fuel pump versions that have the male fuel outlet on the pumps? What i have found is that all the ones that had low fuel pressure all have the new pumps with the male fuel outlet on the pumps themselves. The ones that had the older version had the female fuel outlets on the pumps.

My car was a beast prior to the fuel tank recall done. I had replaced the pumps already 5yrs ago. Then in May of 2015, I got the tank recall done. Drove car home normally, felt fine. But right after 2 days later, when I did a WOT run from 2nd to 3rd my car felt very slow, and just thought it was heat soak issue because it was over 80F out. Then it just didnt get better, and it was just a placebo effect i was dealing with for months.

Then this year I got a dyno session to custom tune it, my AFR's went from 11s down low to almost 14's! for my AFR up top to 6k rpm! Dangerously lean, but still through down 530whp and 640wtq. So that is when I decided to check the pumps pressure. drops to 40psi under WOT.

So I bought new pumps from the dealer, dropped them in fine, and still same issue.

I then took the driver side fuel level side, and fuel pumps from passenger side out from my buddy's car that has the older pumps, and BAM!! my fuel pressure was rock solid!

A lot of the cars I tested didnt even realize they had an issue because they were still smoking vettes, m4's with dps and tunes and ****.

I few guys here have been battling a massive low fuel pressure issue under WOT load. 2nd gear, or 3rd doesn't matter.

Here is what I know. When the car goes in for the tank recall, they actually have the entire tank with the passenger side fuel pumps in it assembled, and the driver side Fuel leveling sender also installed. The tech drops the old tank, and pops in the new and connects it all up.

So with that being said, I decided to test fuel pressure in the following cars locally.

Got fuel tank recall done (full tank swap)
1x E55's = 76psi idle, drops to 40psi from 3k to 4.5krpm (84mm upper, 172mm lower, Mid headers, 2014 M5 3.14" exhaust, 82mm TB, 550cc injectors, looped rail, HE, HE pump, 5 gal trunk tank)

1x E55's = 76psi idle, drops to 40psi from 3k to 4.5krpm (84mm pulley, ECU tune)

1x CLS55's = 76psi idle, drops to 40psi from 3k to 4.5krpm (stock)
1x CLS55's = 76psi idle, drops to 40psi from 3k to 4.5krpm (84mm upper, ECU, TCU tune, Mid headers, HE pump and HE)



No fuel tank recall done at all yet, still original pumps or the older version.
1x E55's = 76-80psi idle, holds 75 psi solid under WOT (84mm pulley, ECU tune)

1x CLS55 = 76-80psi idle, holds 75 psi solid under WOT (72mm upper, 82mm TB, mid headers, 3in exhaust, 5 gal trunk tank, HE and HE pump, ECU, TCU tune)

1x CL55 = 76-80psi idle, holds 75 psi solid under WOT (84mm pulley, ECU tune)

From what I am seeing in the post, all of fuel pressure test show you are all ok at idle. but are you ok under boost and WOT? Because we aren't, lol. Fine at idle, but very low under WOT.

Can any of you provide a fuel test results under WOT? We just attached a manual guage to the rail and taped to the windsheild. So no electrical testers used to rule out calibration etc.

Originally Posted by SICAMG

I run a digital fuel pressure gauge and can tell you my pressure is adjusted to 65psi and stays at 60psi under full boost under very long pulls. My system still has stock pumps but has been very modified from front to rear.

Originally Posted by Mackhack

Before you order these send me a PM with your VIN. The price is way too much.

Originally Posted by BigVic

so did you get all new pumps, tank, fuel sender/level unit? Have you tested your fuel pressure after idle and WOT? I am curious...

Originally Posted by StarvingArtist

This might be something.

There are 4 wires powering 2 pumps, two brown and two red. I put new pumps in myself I noticed the + - was reversed on one side of the plug. I pulled the wire out and moved it, but if you didn't, I'm not sure what would happen. One pump would spin the other way I guess.

Originally Posted by cmattox

I'm currently having this same issue on 2 of my customer e55's... went in to the dealership for recall and now have low fuel pressure at wot and loss of power. Wot drops to about 40psi. Let's figure this out and save these engines

Originally Posted by bbirdwell

It is possible the adaptor harness was not installed so one of the pumps is reverse biased.

FWIW, if the pump is wired backwards the amperage draw is approximately 3 and 1/2 amps (makes sense as it is running backwards and not pumping into the fuel pressure regulator); wired correctly is 13 and 1/2 amps.

Photos attached show the difference.

Originally Posted by SICAMG

After racing for many years I learned right out of the gate with this car that a wide band and fuel pressure gauge mounted inside the car are mandatory. I run the Dyno Tune small square gauge mounted right on top of the steering wheel/dash cluster and it looks real clean and fits like it belongs there. Never any question as to whats going on. This I also how I figured out that running 92psi of fuel pressure was over kill and really hurting the pumps for no reason. Now she's at 65psi and much less stress.

Originally Posted by Max.H

Legend...

How do we check fuel pressure? is there a port to attach a gauge? This should be a cause for concern. Hey I just swapped my fuel pumps. Ive been going lean and my engine is dead. WTH?

This sounds horribly wrong. How could MB allow this to happen? Where is the QC?

Originally Posted by Max.H

Im ordering these pumps and filters for MY 2005 E55. So which ones are these? Good or Bad? I heard something about some pumps you will need a MB wiring kit? Da heck?