Fuel pressure help needed

[Spid]

I am losing fuel pressure as the temperature rises, I have put a pressure sensor on the high pressure side and can see it drop, causing the engine to miss fire. I run a low pressure pump to a swirl pot in the side pod , which I have put a low pressure reg to 5 psi ( hasn't helped) to a Bosch 044 pump across the fuel rails to a reg and back to the swirl pot. I have fitted a new low pressure pump and today fitted a new high pressure pump and still have the problem. Of to Le Mans on the 4th of August any ideas?
Thanks Adam

[Spid]

Using Ultima standard issue low pressure pump

[738 driver]

faulty pressure reg ?

[Spid]

Do they play up when they get warm?

[Storer]

I have a new Aeromotive regulator coming tomorrow to hopefully rectify a similar problem.

I have a temperature sender on the regulator and it only registers 40 to 50 degrees but I noticed "boiling fuel" in the swirl pot after the engine is shut down. You can still touch the pot with your hand so not sure what's going on.

Need to get it sorted as I have a rolling road session in a couple of weeks time.


Paul

[738 driver]

Depends how the particular valve on it works but yes valve performance (volume/pressure) can be affected with temp. You really need to set slightly higher than advised in this installation.... say the required is 58psi.... then set 65 ish or even 70.........the required needs to be there in all running conditions and at all temps which is not easy to accurately maintain in a system with so many hardware variables.

[Spid]

Paul let me know if that does the trick
Just got of the phone to Ultima gave me a few things to check

[deadscoob]

Is it the same reg you both had? I had pressure probs with an aeromotive a1000 which has been sent back for fault finding.

[spatz]

not sure how much fuel the ultima pump can deliver, but I am using a FACET 170l/h to feed the swirl pot.
no problems with temperature rising, although in hot conditions and traffic I hear that at least one of the pumps
is sucking air and making noise. That is going away as soon air can cool the system down.

[Spid]

mine is an a1000

[spatz]

to feed the swirl pot or hp pump ?
is that problem appearing on heavy fuel consumption or even at idling, cruising ?

[Spid]

Loads of fuel flowing back to the tank from the swirl pot even with a good rev. But return from regulator practically stops when you rev it! going to check fuel filters pre and post hp pump

[Graham-P]

I started a thread over on the next page about my lifter pump failing and my Bosch pump pressure going down to around 20 psi and misfiring. I checked my pre pump filter to find it was blocked, difficult to blow through it. I spoke to an engine builder friend and explained what happened and he said that he has rebuilt many carbs due to fueling issues mainly caused by the Bio fuel! He suggested that as my tanks have now seen a few winters with only some fuel in them, there's a good chance that I have had contaminated tanks/fuel over the years and that coupled with the Bio fuel and the tank foam means that filters will block quicker now as this bio stuff tends to break things down quicker now. Now this could be bks or he could have something but my next job is to take out the tank foam and install a lifter pump at the bottom of each tank feeding the swirl pot. The tank foam has a limited life anyway and mine is getting close to six years so it's time for it to go, the fuel lines are only a couple of years old, but I will replace them soon with the latest spec so that when the fuel companies go to 10% or more Bio my system should be able to cope with it.

[Spid]

Filters ok. Plan of attack tomorrow fit 2 hp pumps

[Storer]

Alan

Mine is also an A1000 regulator and I have an A1000 pump.

I have replaced the regulator but not had chance to try her yet. Will do so tomorrow and report back.

I am also fitting a new 10 micron filter. The current one seems OK but it is relatively cheap and easy to do and it may help.

I also fitted a restrictor in the swirl pot return to tank to try to create a slight pressurisation of the swirl pot.


Paul

[deadscoob]

Why would fitting 2 HP pumps solve this? A single 044 if working correctly should be sufficient I would've thought?

So at least 3 owners have fuel pressure problems and all have A1000s. Is it the way the Aeromotive ones work? I'm sure they sell 000s of these and they're high quality, so are there any other consistencies that could lead to this?

[DHGTR]

I guess i will just sit and wait for my pressure problems to come along - i also have an a1000

[738 driver]

Laid-up, patially filled ally tanks will always be subjected to moisture which if not drained will find its way into other components and cause more issues, corrosion, poor running and the like.
If anyone is modding tanks it might be worth fitting an accessible drain cock at the lowest point in your fuel system..or a low-down swirl/header would be the easiest for this simple mod.
Big changes in temp mixed with humidity and petrol are the root of many running issues I'll bet. Changes in fuel quality are not helping this either.

G luck.

[Graham-P]

Fitted a LP Holley pump(HP150 Billet) I had in the garage, a bigger filter and up'd the fuel pressure slighty. Just returned from a mates in Colchester and it seems ok now, fuel pressure started at 65psi and went up to 70psi at the end of the journey same on the return journey, about a 40min run, Not sure if that's too high or not?
The only difference that I noted was that my exhaust note is louder, not sure if all the misfiring etc last week has anything to do with it.
Looks like I might make the factory open day.

[Spid]

Fixed ! Found another fuel filter between the swirl pot and the hp pump that was full of crap. Must be a really fine one because the one before it was fine