P7100 fuel pressure issue

superdutyfarmer

superdutyfarmer

New member
Working on my 4bt drag truck/street toy. Have it up and running but having an issue with fuel pressure I don't quite understand and am looking for some input.
Fuel system I built was using #line from sump to an ff105 filter before pump, Aeromotive fuel pump then to a 5micron fleet guard filter and then to injection pump. Holds 60psi idle but on full run dropped to about 5.
Bypassed the secondary filter and it will maintain 10psi full throttle run.
Was plumbed up using 3/8" hose from Aeromotive to injection pump; tried running 1/2" and seen no pressure difference.
Have adjustable fuel pressure regulator on return side of injection pump, will a high speed check valve be worth a try??

When the pump shop built the pump they said it needs 35psi to make full power at full rpm.
 
Using an a1000? Where is the regulator in the system?

Fwiw I have 10an from the sump to a 100 micron prefilter, to the pump, to the filter/water separator and then up to a dual feed that is 8an. My regulator is on the return side.
 
I've been fighting fuel pressure / volume issues all season with my truck. I got the single AD up to 65psi at idle but at WOT it would drop to 27psi. I have 1/2" fuel lines from fuel cell to pump and pump to injection pump. Working with Air Dog, just plumbed in a 2nd fuel pump to front feed the injection pump to try and get the volume high enough at WOT. Both pumps bottom feed off of my fuel cell, supply 1/2" lines to the injection pump with check valves at the injection pump before the lines enter incase of a single fuel pump failure, return side is -6 an line to a regulator and then returns back to the tank. Haven't gotten to test it yet since I've been building the transmission and get it all changed over from the th400 / divorced np205 back to a 47re and 241dhd.

Hoping to have some data on this setup by the end of the week and make my first race Saturday.
 
Pressure regulated on return side of pump before it joins the injector return back to tank

Yes it's an a1000 I can't believe that the pump can't keep up with the demanded fuel if you see so many 6cyl Cummins using them with same injection pump

I am taking fuel pressure reading at inlet of injection pump
 
Last edited:
Ok, similar to how mine is. Can you check the pressure on the return side? The regulator I use has a port on it and that is where I measure my fuel pressure at.
 
I'm running an A1000 on my p-pump 24v with a 13mm pump and twins. Also running an aeromotive regulator on the return side at 60psi. I didn't see much pressure drop until I got to the 1000hp mark and even then it only went down to 40ish psi. So the pump is plenty capable.
 
I guess I could check fuel pressure on backside of pump before the regulator but I don't believe the reading would be any different. Other thing I was curious on was I wonder if this pump is getting tired? I bought it supposedly only used for one dyno run on engine dyno or something to that extent. But it was used and it has been on this truck for about a year and maybe 1000-1500 miles.
 
That is a possibility but I know of quite a few of these pumps running around. They seem to just die vs. slowly going away.
 
Could getting tired. Mine is going on 7 years with over a 100 sled pulls and a couple thousand street miles. You can send them in to Aeromotive to have them rebuilt for a fairly decent price.
 
When was the last time you changed the pre filter? That's a lot finer filter than I like to use on the suction side. The ff105 is an awful small filter that's fine which could possibly get stopped up much sooner than you anticipate.
 
I have heard of issues running a fuel filter on the suction side. I have an Allstar Performance inline filter with a removeable stainless screen, between the fuel cell and fuel pump. I have a spin-on filter between the fuel pump and injection pump.
 
jedeka said:
I have heard of issues running a fuel filter on the suction side. I have an Allstar Performance inline filter with a removeable stainless screen, between the fuel cell and fuel pump. I have a spin-on filter between the fuel pump and injection pump.
Click to expand...

I was going to mention this as well. I've never liked running a spin on type filters on the suction side, only on the pressure side. I'm currently running a Summit brand 100 micron pre filter SUM-230117-B, attached directly to the inlet of the pump.
 
Had you bypassed the prefilter yet? I know aeromotive and holley (pump I run) recommend only a 100 micron stainless media filter before the pump.
 
I have a spin on 100 micron water seperator before my pump with regular filter after the pump for the last 3 years and my Fuelab runs constant 85-105 psi unless that water seperator is starting to clog up
 
You need to measure fuel pressure on the return side of the pump pre regulator.. This will give you a true cavity pressure reading.
 
You must log in or register to reply here.
Back
Top