E46 Fanatics Forum banner

HPF Fuel issue (Out of Gas at 1/4 Tank---Fuel Cutoff at 6k)

8K views 70 replies 23 participants last post by  gc86 
#1 ·
I have a stage 3 HPF/ProEFI turbo system on my car that I usually run E85.
I know my two inline fuel pumps are walbro 255lph not sure what is in tank yet...maybe someone might know.

Anyways, I do know at 1/4 tank of gas (whether E85 or 93oct) I am out of gas but not necessarily empty in the tank.

When I get on it or on dyno for tuning the car runs out of fuel at 6k rpms and fuel is cut off (or so that is how I understand it) and the car bucks then goes again.

Have tried getting this as well as a long, long list of issues fixed as Chris didn't want to make anything work with the ProEFI system, etc.

Lot of BS. But what I really need is this issue fixed and am wondering if anyone else has experienced similar or same issue.
 
#3 · (Edited)
Hi, Tony, the fuel level issue I'm thinking has something to do with #2 and #3 here:
http://realoem.com/bmw/showparts.do?model=BR93&mospid=47708&btnr=16_0373&hg=16&fg=15
I'm not sure what your setup is, but if one of the two fuel level sensors were disconnected in favor of a second in-tank pump, the reading will be off, or if the "Jet sucking pump" was removed for any reason, it probably can't get get the gas from the bottom of the driver's side of the tank over to the pump.

You might have to pull the seat out and just see what's in the tank...

About the fuel cut-off, AMG-ETR might have a point about the dyno limiter.
One reason for the bucking could be that the OEM DME cuts off at 6300, pulls timing etc, but the ProEFI doesn't have a limiter and it keeps firing. :hmm:
Make sure the car is in dyno mode before your next pull if you haven't already...

Let me know next time you're in the area and we can mess with some stuff... :D

Has your ECU been flashed for permanent dyno mode? That's the reason why it's cutting off at 6K RPM on the dyno.

If you don't have it flashed for dyno mode - then you need to manually put it yourself: http://www.m3post.com/forums/showthread.php?t=308906

-Kevin
Kevin, that method only works on a handful of cars, it's not really good "universal" advice.
(also, every single number that guy posted is wrong, so I wouldn't trust him)
The easy and universal method is to drive the car on the dyno at over 25, then shut it off, pull the key out and while it's rolling start it again and you can dyno to your redline.
This kills the DSC until your front wheels get to 25 again and then DCS turns itself back on.
 
#4 ·
A few things can be happening. First is dyno mode I was stated. Second is that the HPF fuel system is junk, sorry no other way to say it. Third is the PROEFI is protecting your engine when it senses fuel pressure dropping. What you need is a Saad Racing Stage two fuel system, this will end all your fuel problems. Let us know if we can help.
 
#6 ·
When it was on dyno it was Larry from SP and he was doing the on and off technique. So I am going to rule that one out.

Another tid bit is I changed the two inline figuring they may be bad and had no issue of bucking for a few days, then it started up again.


Now here we are today my short block is cracked, just got word 10 min ago.

So I need to source either a block or even motor debating if I want to stick with built motor or go with stock. FML
 
#9 ·
Damn sorry to hear that....


last few M3s that blew up/lifted heads were ProEFI cars....ill wait on the switch lil more I think...
 
#29 ·
Yup sucks Tony...I'll post some pics of my fuel system next week when I get back to my car...I would highly recommend it over the Saad setup.

James nice seeing you in this thread...Tony I'm sure James has more of a focus on helping you solve your issue he is a great guy.
 
#30 · (Edited)
That looks like a red fuel lab filter up front and a bosch in the middle.. I swear the walboro's are not that fat. I could be wrong though.
It's definitely a Walbro pump, an external one though. The one you posted a picture of with the Bosch 044 is the internal Walbro pump. Also the red piece looks like an Aeromotive fuel filter to me, don't think I see any electrical leads/wires going to it.
 
#57 · (Edited)
I am having a similar issue, running out of gas at 1/4 sometimes 1/3 tank with my car with the SADD fuel system, SP is suppose to be working with you guys on figuring it out, haven't heard back from them yet though..
The SAAD fuel system will provide proper fuel to the engine but that's only if there is fuel to feed.. Under hard acceleration or hard turns the fuel is going to slosh to one side and leave the pickup dry. The best way to prevent this is by running a surge tank setup like Kenton just installed in conjunction with your existing fuel setup.
 
#36 ·
The HPF fuel system has many things wrong with it.
1. The pickup in the tank is a -3 made of plastic and it can move! We use mandrel bent stainless steel and it -8!

2. HPF uses rubber fuel lines that are not compatible with E85 and 90 degree fitting that will not flow for heavy use. Again we use mandrel bent stainless steel and teflon braided steel lines for compatibility with all fuels. NO 90 degree fitting, all smooth radias turns for maximum flow.

3. They use a regular filter, we use a E85 glass filter.

4. There pumps are inline, ours run in parallel for more flow.

5. The wire to the HPF pumps are very fine and can not maintan good current supply. Ours are much heavier.

6. Walbro pumps do not perform well under high PSI, we use Bosch 044, they have very little flow drop at high PSI.

I can keep going but you are getting the picture, you get what you pay for, this is the best fuel system you can put on a M3. Not because its mine, but because we built it sparing no expense and to be the best.

Last point I would like to make. For the people considering putting a "surge tank" fuel system in a street car, don't do it. You are removing fuel from your fuel tank and placing it in a tank in your car, how much sense does that make, if you get into an accident and the tank or line ruptures you could be burned alive. Buile the fuel system right and leave the fuel where it belongs, in the fuel tank
 
#37 ·
I'm no expert but the idea of putting multiple pumps in series says, "We added another pump to fix a fuel pressure problem". A trial and error, fix it so it works approach.

When you design a system from the ground up, you know what the specs of your project are and engineer a solution with an appropriate margin. A parallel pump layout is a good indication that an engineering approach has been take, the capacity of each unit is added provides until final specifications are met.

Obviously if care is taken to optimise aspect of the system, like mandrel bends, corrosion resistance, as well as a properly designed electrical circuits you have a system build to more demanding specification.

There is no reason why a "surge tank" cannot be part of the final design, even in a street car. It's absurd to suggest it shouldn't be done.
 
#38 ·
In my opinion its always safety first. To put a surge tank full of gasoline in your trunk, in the M3 that would put it in the passenger compartment, is not safe in a street car. If you are rear ended and the tank or line ruptures the fuel is now in the car with you. In the factory set up, if it ruptures, its outside of the car. This could be the difference of you getting out or not. Not worth it to me for a street car. Everyone can make there own decision. Plus you loose storage space:)
 
#39 ·



This may be obvious but under the plastic under tray/whatever its called...there is another walbro 255lph inline pump. So wouldn't that be a parallel set-up?

What are the factors that make a parallel set-up if this is not?

The lines don't look like rubber either. This fuel system is different then a normal HPF fuel system.
 
#46 ·
Now I see it better. What was in the tank of that customer's car?

Didn't we have fuel pressure issues when you had it here??

ALso I believe that this is the car that came from HPF with absolutely NO TUNE in it!! It barely ran! The a/f's were pegged at 9.0 almost all of the time!
Yeah that is on the original post Larry :D Never heard from you either, not sure if you got my messages or email?

Anyways, I am not trying to defend HPF in any way. Just trying to get the facts straight and see for myself and others with the same fuel issue what needs to be done to the existing system to make it up to par. Then, it would be up to each person to decide what their best option is.
 
#68 ·
Damn, just read the 1st & 2nd pages.... sorry to hear of all this tony

I share one issue with you, my car runs out of fuel very soon AFTER the light goes on and the needle is sitting 1/2" ABOVE the "E" line and the computer says you have 50miles left
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top