Fuel pressure drop need HELP
 

ok guys I have been fighting a loss in fuel pressure in my car. At WOT anything past 5800RPM I lose 18PSI of pressure.

So far I have strair hot wired the pump power and ground side so I know it is getting 14.8 volts. I have the hinson fuel system Walbro 255HP pump with -6 lines for the supply. The tanks is over 1/2 full.

What could be the trouble here guys I have tried everything and it still just falls off at the top end. I think I have a bad pump thats they only thing I can see. Anyone else have something to add here. Oh it is doing this on the Dyno, and driving!

here is the pump before it went in the tank
http://i61.photobucket.com/albums/h4...7/IMG_2485.jpg

im not sure if a single 255 can fill a -6 line...add another pump and you should be set.

really, I mean it works at idle and all the way up to 5800 then it drops off.



I was thinking of steping it up to this pump.

http://www.boschfuelpumps.com/images...-fuel-pump.jpg

Bosch 040

The reg is like this one.
http://www.jegs.com/images/photos/02713109.jpg

The filter is this size but not this one.
http://www.jegs.com/images/photos/02712301.jpg

This is the 1st I have heard about the 255 not being able to fill a -6 line???

That's crap. A 255 pump supplies the same volume of fuel regaurdless of the size of the line. I'm courious if your reg is working right.

Re'

ya I'm wondering that too. but I have not messed with it yet just getting some thought from others.

ya...replace only the reg..then post back the results

WTF Aeromotive will not sell you a rebuild kit you have to send it to them....there is nothing to is WTF is the deal.

If you are going to step it up to a Bosch pump, go with the 044 rather than the one you mentioned above. The 044 can be intank or external.
I have read go things about it and hence will be using it in my current project.
What ever pump you decide to go with, buy from a seller who can guarantee its 100% Bosch or walbro if you go that route....theirs too many fake chinese pumps that look exactly like the original product.

ya I know about the fake pumps.

The 040 has the same specs as the 044 but the whole bottom of the pump is a screen pickup, rather then an inlet and out like the 044. Its rated to support over 700HP

SABRE 02.

Most fuel companies do not sell replacemnet parts. The product liability is too great. Also do you know how to seat the diaphragm in a regulator?

I did it once. But you can set me strait here.

Actually they are very different.

These are the Bosch specs
040: 100 l/hr @ 6.5bar (94psi)
040: 200l/hr @ 5 bar (72psi)
Attachment 113163

the 040 is recommended for a max of 400hp NA

on the flip side the 044 is very large and a sock( strainer) for it costs $50

Hey I dont know where you are getting that info from but it seems really off from my site.

Bosch 040 fuel pumps are universal style in tank fuel pump replacements recommended for vehicles exceeding OE specifications. The Bosch 040 fuel pump is one of the only in tank fuel pump that can be compared with the Walbro 255LPH High Pressure series fuel pumps for use in vehicles with up to 700 horsepower.

Bosch 040 Fuel Pump Specs:
Bosch Part Number: 0 580 254 040
Minimum Current: 12 Volts
Operating Pressure: 94 PSI (6.5 Bar)
Minimum Flow @ Outlet: 80 GPH (300 LPH)
Fuel Pump Location: In Tank
High Temperature Reduction: 8 GPH (30 LPH)
Weight: 930 Grams (2.05 Pounds)

Fuel Pump Connections:
Inlet: Open Base
Outlet: M10 x 1.0
Electrical: Positive M6 / Negative M5

http://www.boschfuelpumps.com/

and by your math the 040 still out flows a Walbro 255 casue it is rated at 255LPH at free flow it does not come close to 200 at 4 bar.

The info is from a list of pdfs from Bosch. you can see the pdf attached. Im not trying to talk you out of using the 040 or compare it to the walbro. If its the 040 you want,by all means go for it. I will tell you though its not rated at 700hp and iits not the same as the 044.

As far as boschfuelpumps.com is concerned, not only is their info misleading but, if you purchase a pump from them chances are you will not get it.I even doubt they are still in business
http://www.rx7club.com/showthread.ph...boschfuelpumps

Anyway since Im not helping you much with your original problem I'll cut the yapping. Hope you figure it out.

wow man thanks I will not get a pump from them now.