Low Fuel Pressure (WOT ONLY)

OP
OP
a10jay

a10jay

Member
Joined
Mar 10, 2022
Threads
1
Messages
12
Reaction score
0
Location
Richmond, CA
First Name
John
Vehicle(s)
2019 Mustang GT (PP1)
Toby had the same issue with the DW400, his buddy end up installing his E85 fuel pump and all issues went away. Check out this Video and fast forward to 30:20, he will talk about how the DW400 was giving him low fuel pressure at WOT
Toby’s solution was a Fore Innovation return style fuel pump assembly for his boosted car. I have a basic bolt on 19’ gen 3. I shouldn’t have to drop a whole lot of money for a return style system for a NA car to run a 100%.

 

Soulja4187

Well-Known Member
Joined
Apr 1, 2020
Threads
46
Messages
1,451
Reaction score
769
Location
Greenacres, FL
First Name
David
Vehicle(s)
2021 Mustang GT Premium & 2022 Audi A5 S-Line
Toby’s solution was a Fore Innovation return style fuel pump assembly for his boosted car. I have a basic bolt on 19’ gen 3. I shouldn’t have to drop a whole lot of money for a return style system for a NA car to run a 100%.
DW400’s are know for giving issues with low fuel pressure on boosted and non boosted. If I was you I would invest in the JMS bap instead of the Deatschwerks hardwir hardness kit.
 

WildHorse

N/A or GO HOME
Joined
Jun 28, 2017
Threads
189
Messages
7,047
Reaction score
4,976
Location
HomeWorld: CLASSIFIED
Website
www.instagram.com
First Name
ⓇⒾⒸⓀⓎ ⓈⓅⒶⓃⒾⓈⒽ
Vehicle(s)
'17 S550
Vehicle Showcase
1
I just purchased a JMS BAP. Should be here on Wednesday. Hopefully it fixes it.
Did you email DW with your observations ?
 
OP
OP
a10jay

a10jay

Member
Joined
Mar 10, 2022
Threads
1
Messages
12
Reaction score
0
Location
Richmond, CA
First Name
John
Vehicle(s)
2019 Mustang GT (PP1)
Did you email DW with your observations ?
DW is just as confused as we all are. Everyone’s response has been “that’s odd” and “check the fuel lines, test the fuel pump, check your ground wires, check for good voltage”. After I’ve told them I have done all that they basically run out of possible solutions for my problem.
 

WildHorse

N/A or GO HOME
Joined
Jun 28, 2017
Threads
189
Messages
7,047
Reaction score
4,976
Location
HomeWorld: CLASSIFIED
Website
www.instagram.com
First Name
ⓇⒾⒸⓀⓎ ⓈⓅⒶⓃⒾⓈⒽ
Vehicle(s)
'17 S550
Vehicle Showcase
1
DW is just as confused as we all are. Everyone’s response has been “that’s odd” and “check the fuel lines, test the fuel pump, check your ground wires, check for good voltage”. After I’ve told them I have done all that they basically run out of possible solutions for my problem.
Which leaves ?
 


mangosmoothie

Well-Known Member
Joined
Nov 8, 2021
Threads
9
Messages
125
Reaction score
70
Location
Flagstaff
First Name
Casey
Vehicle(s)
2019 Boolet
what is keeping the dw400 from bottoming out in the bucket, smooshing the sock, and causing a decrease in flow to the pump? That could cause what you're seeing.

I just looked at a bunch of install videos and directions, everyone is just ram rodding the pump in there and hoping frictions stops that from happening?

The stock pump clips in so that can't happen
 

Grimreaper

Well-Known Member
Joined
Jan 23, 2019
Threads
12
Messages
333
Reaction score
112
Location
Dallas
Vehicle(s)
2017 GT
Fuel filters right after the pump. Did you replace pump assembly or just the pump twice?

Also I'd pull hat up enough to see if clamps are leaking on the tube you replaced. What type of clamps?
 
Last edited:
OP
OP
a10jay

a10jay

Member
Joined
Mar 10, 2022
Threads
1
Messages
12
Reaction score
0
Location
Richmond, CA
First Name
John
Vehicle(s)
2019 Mustang GT (PP1)
what is keeping the dw400 from bottoming out in the bucket, smooshing the sock, and causing a decrease in flow to the pump? That could cause what you're seeing.

I just looked at a bunch of install videos and directions, everyone is just ram rodding the pump in there and hoping frictions stops that from happening?

The stock pump clips in so that can't happen
I positioned the sock properly before putting it in and I didn’t snip the tabs like most people do. The fuel pump doesn’t bottom. The fuel pressure when under 5300RPM’s hold a consistent pressure of 84-86.
 
OP
OP
a10jay

a10jay

Member
Joined
Mar 10, 2022
Threads
1
Messages
12
Reaction score
0
Location
Richmond, CA
First Name
John
Vehicle(s)
2019 Mustang GT (PP1)
Fuel filters right after the pump. Did you replace pump assembly or just the pump twice?

Also I'd pull hat up enough to see if clamps are leaking on the tube you replaced. What type of clamps?
I’ve replaced the fuel pump twice. The whole pump assembly is perfectly fine, no issues there. Permanent clamps that were provided by Deatschwerks in the installation kit for the DW400.
 
OP
OP
a10jay

a10jay

Member
Joined
Mar 10, 2022
Threads
1
Messages
12
Reaction score
0
Location
Richmond, CA
First Name
John
Vehicle(s)
2019 Mustang GT (PP1)
Here are the logs if it helps. First 2 pics are for MAF, AFR, and Fuel Trim readings. 1st pic being cruising and 2nd pic during WOT. Last 2 pics are for fuel pump pressure. 1st pic being cruising and 2nd pic during WOT.
13E4350D-0F0C-4D0D-A5DF-B01161BF779B.png
759D9D17-0B7C-40A9-A92B-33391AD7A545.png
16CBE648-6268-4D85-AF7B-ACECA4C0CEBD.png
60E61875-6435-455B-A78E-A4DEB104299E.png
 

mangosmoothie

Well-Known Member
Joined
Nov 8, 2021
Threads
9
Messages
125
Reaction score
70
Location
Flagstaff
First Name
Casey
Vehicle(s)
2019 Boolet
The fuel filter isn't serviceable. It's part of the pump assembly. The line off the fuel pump goes to the filter within the assembly. If it's clogged, it can cause problems too. Might be correlated to your oem pump failing.
 

 
15 - Steeda - 5
Top