F Series N55 Stage 2 LPFP Troubleshooting - N54Tech.com

ArmadaCT · 11:03 AM

Hi all

I tried installing a fuel it stage 2 lpfp yesterday, but ran into some trouble once it was in. With the new lpfp, the car would start, idle for a couple minutes, and then die out. In between these idling sessions, trying to start the car would just result in cranking with no luck. I've heard people say the car needs to adapt to the new pressure of the walbro 450, but the car threw the two following codes:

481B03 - Control current, fuel-pump control, too low
481B04 - Control current, fuel-pump control, lacking

So I'm guessing this means that the EKPG unit on my car isn't strong enough for the additional current drawn by the new pump right? Does this mean I need to order a new EKPG in order to run the stage 2, and how do I go about coding one if so?

Thank you very much!

M-terkait · 09-05-2018, 05:49 AM

Quote:

Originally Posted by ArmadaCT

Hi all

I tried installing a fuel it stage 2 lpfp yesterday, but ran into some trouble once it was in. With the new lpfp, the car would start, idle for a couple minutes, and then die out. In between these idling sessions, trying to start the car would just result in cranking with no luck. I've heard people say the car needs to adapt to the new pressure of the walbro 450, but the car threw the two following codes:

481B03 - Control current, fuel-pump control, too low
481B04 - Control current, fuel-pump control, lacking

So I'm guessing this means that the EKPG unit on my car isn't strong enough for the additional current drawn by the new pump right? Does this mean I need to order a new EKPG in order to run the stage 2, and how do I go about coding one if so?

Thank you very much!

it shouldn't draw much current at idle.
I'd check connections or try to test the lpfp outside the car.

zole2112 · 09-05-2018, 09:59 AM

What M-t said, I had no issues when i installed my stage 2 lpfp.

ArmadaCT · 09-05-2018, 10:09 AM

Quote:

Originally Posted by M-terkait

it shouldn't draw much current at idle.
I'd check connections or try to test the lpfp outside the car.

Okay will do, should I just be checking for flow rate? According to walbro it should be about 6L/min

zole2112 · 09-05-2018, 10:16 AM

Quote:

Originally Posted by ArmadaCT

Okay will do, should I just be checking for flow rate? According to walbro it should be about 6L/min

Make sure you check the connections to the pressure sensor and filter on the bucket as well. I'm not sure if you would get a code if they are unplugged.

ArmadaCT · 09-05-2018, 11:44 AM

Okay so I did some testing with the stage 2 and stock pumps in the car, and I'm back to thinking its the EKP thats failing under high amperage. Used a scan tool to read the live data for the fuel pump ecu that shows current going to the pump (always at 12.9V). I took videos but im not sure what the best way to share them here would be.

The stage 2 starts off peaking out at 16 Amps, makes sense because thats what the walbro should be running at the ideal 70-80 psi. After a couple seconds of maintaining that current, the reading plummets down to the stock fuel pump current in the upper 6 Amp range, and after trying to maintain that the pump dies when the current falls below 4 Amps. Also had my hand on the EKP and it quickly became too hot to touch

After putting the stock pump back in, I read the current to the pump again and it stays perfectly within the 6.5-6.9 Amp range indefinitely.

Checked all my connections.

I'm pretty certain its the EKP. My 335 is a 6/2012 manufacture date and came with a SWFL 000.129.002 EKP. Just ordered a new SWFL 000.131.001 EKP that came in all the 2013+ manufactured models. Hopefully this will handle the extra current, or maybe mine is just old

New EKP gets here next week, will post results. In the meantime, any thoughts anyone?

zole2112 · 12:29 PM

Quote:

Originally Posted by ArmadaCT

Okay so I did some testing with the stage 2 and stock pumps in the car, and I'm back to thinking its the EKP thats failing under high amperage. Used a scan tool to read the live data for the fuel pump ecu that shows current going to the pump (always at 12.9V). I took videos but im not sure what the best way to share them here would be.

The stage 2 starts off peaking out at 16 Amps, makes sense because thats what the walbro should be running at the ideal 70-80 psi. After a couple seconds of maintaining that current, the reading plummets down to the stock fuel pump current in the upper 6 Amp range, and after trying to maintain that the pump dies when the current falls below 4 Amps. Also had my hand on the EKP and it quickly became too hot to touch

After putting the stock pump back in, I read the current to the pump again and it stays perfectly within the 6.5-6.9 Amp range indefinitely.

Checked all my connections.

I'm pretty certain its the EKP. My 335 is a 6/2012 manufacture date and came with a SWFL 000.129.002 EKP. Just ordered a new SWFL 000.131.001 EKP that came in all the 2013+ manufactured models. Hopefully this will handle the extra current, or maybe mine is just old

New EKP gets here next week, will post results. In the meantime, any thoughts anyone?

My build date is 12/2012, not sure what EKP I have in mine. Actually Real OEM shows the same part number for both 16147358144.
Real OEM shows that the same EKPM is used on our cars until it changed to 16147426095 on 10/2013 build date and used until 6/2016.

Maybe yours is failing, I'm wondering if it's getting hot and with the added draw from the Walbro it can't handle the amperage demand so it shuts down the pump, as you are thinking.

zole2112 · 09-05-2018, 12:07 PM

http://www.n54tech.com/forums/showthread.php?t=39023
Some info that might be of interest

ArmadaCT · 09-05-2018, 12:28 PM

Quote:

Originally Posted by zole2112

http://www.n54tech.com/forums/showthread.php?t=39023
Some info that might be of interest

This is good! Looks like these EKPs are pretty much expendable, although coding looks like PITA. Someone ought to marked heat sinks for them

zole2112 · 09-05-2018, 01:08 PM

Quote:

Originally Posted by ArmadaCT

This is good! Looks like these EKPs are pretty much expendable, although coding looks like PITA. Someone ought to marked heat sinks for them

I'm glad you posted this issue, I think I'm going to take a look at mine and probably add a computer fan to blow on it to keep it cool.

ArmadaCT · 11:10 AM

Bumping because I've encountered another issue.

Got the new EKP in today, swapped it out and, behold, the car does not run. Traced it to a blown 20A fuse for the EKP. Disengaged battery, replaced fuse, popped again soon as I plugged battery back in. Took off battery again, replaced fuse, swapped stock EKP back in, works fine.

I figure this is because the new EKP is a newer model than my stock one. But I'm not sure what to do here.

I'm like 95% sure you can't put a bigger fuse in the relay because of fire hazard right? But would a 30/40 amp fuse be able to handle the increased current since the more recent EKP seems designed to draw more current anyway? Otherwise if my stock model cant be upgraded then i guess a stage 2 LPFP is just not an option for me.

I guess what I'm asking is, if I upgrade a part in my car that pulls more current than the stock one, is it electrically sound to increase the amperage of its fuse as well? Or am I just asking to start a fire?

tho · 09-11-2018, 09:20 AM

Quote:

Originally Posted by ArmadaCT

Bumping because I've encountered another issue.

Got the new EKP in today, swapped it out and, behold, the car does not run. Traced it to a blown 20A fuse for the EKP. Disengaged battery, replaced fuse, popped again soon as I plugged battery back in. Took off battery again, replaced fuse, swapped stock EKP back in, works fine.

I figure this is because the new EKP is a newer model than my stock one. But I'm not sure what to do here.

I'm like 95% sure you can't put a bigger fuse in the relay because of fire hazard right? But would a 30/40 amp fuse be able to handle the increased current since the more recent EKP seems designed to draw more current anyway? Otherwise if my stock model cant be upgraded then i guess a stage 2 LPFP is just not an option for me.

I guess what I'm asking is, if I upgrade a part in my car that pulls more current than the stock one, is it electrically sound to increase the amperage of its fuse as well? Or am I just asking to start a fire?

IMO, you're just asking to start a fire by putting a larger fuse in place.

The fuse is in place to protect the wiring. If the wiring gauge is not sufficient for 30/40 amps, than increasing the fuse size only changes which part burns up first. If you want to put a 30/40 amp fuse in place, you would want to re-wire accordingly.

ArmadaCT · 09-15-2018, 10:53 AM

Alright bumping again for update

First EKP replacement was defective, sent it back, no problem. Second EKP came in today and started the car up after a few tries. Works just fine on stock LPFP.

Swapped in stage 2 and once again I have the same issue. Car idles for a while at high current then dies in about a minute after dropping under 4 Amps.

Im starting to think that my car itself is just not wired in some way to handle a 450, this fuel pump really knows how to inflict a sense of despair in a man

Got an appt with an indie shop who can code the new EKP to my car, I think my hail Mary will be asking them if they can figure it out.