DW400 Fuel Pressure Dropping During WOT - Whipple Stage 2

[TEXAS HEAT]

The lift pressure is supposed to drop to 55 psi at idle iirc. I found that with an 18v bap and no tuning changes it would run at 73 psi all the time because the needed dc was below the min dc. Reducing min dc in the tune made no difference. Changing the pump voltage table made no difference. I am told that most tuners say don’t worry and let it run at 73 psi all the time. Btw, the in-tank relief valve is set at 73. I finally found success in modifying the fuel pump pwm slope. I think more time spent adjusting slope AND offset could improve control further. It is on a PID control loop but the slope (and offset) has to be modified to get it within control bounds.

I can definitely report that my lift pump pressure at idle on my current tune is almost 80psi at idle with the BAP plugged in

when not connected it hovers between 65-70 iirc.

Sponsored

 

[jr16]

Once you're hitting these power levels and need for fuel, full return style system is by far the safest and most reliable way to hit that and ensure proper tuning.

Lethal Performance 2018+ Mustang GT Return Style Fuel System (Whipple/Edelbrock E-Force Supercharger)

#teamlethal #lethalperformance

 

[TEXAS HEAT]

Thanks for the knowledge here Mike, greatly appreciated.

I agree!

My apologies for hijacking your thread, but Mike seems to have a lot of knowledge on the subject and is willing to share, where most tuners don't or won't.

 

[Face]

I agree!

My apologies for hijacking your thread, but Mike seems to have a lot of knowledge on the subject and is willing to share, where most tuners don't or won't.

No worries!

I just raised the pump slightly in the bucket and it did the same thing unfortunately. So this is now two pumps, two sets of pump lines and now raising the pump- all to no avail. BAP will be here in a couple days, we'll see what happens then.

 

[WildHorse]

BAP will be here in a couple days, we'll see what happens then.

Shouldn't need a BAP with a DW400. I'd start looking at the tune IMHO. DW provides the tuning DATA for it.

 

[Face]

Shouldn't need a BAP with a DW400. I'd start looking at the tune IMHO. DW provides the tuning DATA for it.

I'm sure Lund is pretty on point with these, but thanks for the suggestion.

 

[WildHorse]

I'm sure Lund is pretty on point with these, but thanks for the suggestion.

Everybody misses something once in a blue moon, & you've pretty much tried everything. Next time it's out, take some detailed pics of the assembly.

 

[TEXAS HEAT]

56LB- but its not an issue with the injectors- the issue is with the HLFP which is causing a drop in pressure in the upper RPM range, also affecting the high pressure rail too.

My lift pump pressure isn't affecting the HPFP side of things. The high side maintains 2900psi throughout the entire pull.

 

[engineermike]

@Face can you log lift pump DC and plot it with pressure and rpm?

 

[Face]

@Face can you log lift pump DC and plot it with pressure and rpm?

I'm sure I could if I had the proper config? I just have whatever .dle lund sends over. Or maybe its already being logged- is there a specific abbreviation to look for in the logs? (sorry, some of the tuning stuff is new to me but I'm learning lol)

 

[TEXAS HEAT]

I'm sure I could if I had the proper config? I just have whatever .dle lund sends over. Or maybe its already being logged- is there a specific abbreviation to look for in the logs? (sorry, some of the tuning stuff is new to me but I'm learning lol)

The parameter you seek is part of Lund's defaults (fpump_dc)

 

[Face]

@Face can you log lift pump DC and plot it with pressure and rpm?

Sorry, I had to load a different config- but here it is.

 

[sabtaj1]

I never had any issues with mine. Actually just pulled it out a few days ago and did a Fore L2 and 1050’s. If you were closer I could let ya try mine as it’s complete and sitting in the shelf now.

 

[Face]

I never had any issues with mine. Actually just pulled it out a few days ago and did a Fore L2 and 1050’s. If you were closer I could let ya try mine as it’s complete and sitting in the shelf now.

I appreciate that brother, thank you.

 

[brianbr]

Sorry, I had to load a different config- but here it is.

Are you losing battery voltage thorough the pull at all?

Sponsored