100+ PSI fuel pressure

[FX4 F2-Fifty]

After i talked to the guy from aeromotive and he said my old pump looked like it was putting out too much PSI i decided to go take a look. I checked my fuel pressure before the heads instead of at the regulator after the heads. At the aeromotive regulator after the heads i have 55psi,but before the heads the gauge pegs out at over 100psi. I have verified both with mechanical gauge as well. The only two things i can think of is the regulator, or the fuel block. I can back off all the way on the regulator and it drops to under 30 psi and i can hear the pump change pitch, but before the heads the pressure stays at 100psi or more. The pressure reading before the heads is taken at the fuel block that i had made to delete the fuel bowl.

Since the truck is not running so there is no demand for fuel, when i back off on the regulator why does the pressure not drop before the heads?
Key off, both pressures drop to zero like they should.

 

[mgeistman]

After i talked to the guy from aeromotive and he said my old pump looked like it was putting out too much PSI i decided to go take a look. I checked my fuel pressure before the heads instead of at the regulator after the heads. At the aeromotive regulator after the heads i have 55psi,but before the heads the gauge pegs out at over 100psi. I have verified both with mechanical gauge as well. The only two things i can think of is the regulator, or the fuel block. I can back off all the way on the regulator and it drops to under 30 psi and i can hear the pump change pitch, but before the heads the pressure stays at 100psi or more. The pressure reading before the heads is taken at the fuel block that i had made to delete the fuel bowl.

Since the truck is not running so there is no demand for fuel, when i back off on the regulator why does the pressure not drop before the heads?
Key off, both pressures drop to zero like they should.

is the fuel bowl deleted? if not check inside it, maybe some blockage? if your gauge readings are 100% correct then you have a restriction somewhere between the two gauges. thats the only thing it could be.

 

[SICKS LITER]

sounds like a regulator problem unless there is to much volume of fuel for your regulator and or to small of lines fuel lines.

 

[FX4 F2-Fifty]

Fuel bowl is deleted, and the fuel block could possibly be the restriction. i just took apart the regulator and it looks great inside. Not really too much that could fail in there either. So i think i have ruled it out for the most part. I checked and the return line is not plugged. so thinking the fuel block might be to blame, but not sure. other things i could think of would be the banjo bolts in the rear of the heads, 90 degree fittings in the front of the heads. the smallest orifices in the fuel block are .339 or 11/32. too small? should be bigger than the 90 fittings.

 

[mgeistman]

so when you say your reading pressure before the heads do you mean before or after the fuel bowl delete block? banjo bolts in the rear and 90's in the front could very well be the issue. if your reading pressure at 100 psi in between the delete block and the heads than its not the delete block thats your restricion. i would say its the banjo's. jmo

 

[FX4 F2-Fifty]

The pressure reading is coming off the fuel block. Im doubting it is the fuel block as the orifices in the 90 fittings are smaller than the smallest orifice in the fuel block. The fuel block is custom i had it made at a local machine shop. Im with you on thinking it is the banjos. It is an older elite fuel system and calls for the banjos to be gutted and installed in the rear of the heads for the return.

 

[mgeistman]

dam gettin to those banjo's is a bitch!

 

[FX4 F2-Fifty]

dam gettin to those banjo's is a bitch!

ill have the uppipes out next week so that will make it easier.

 

[mgeistman]

there ya go!! you getting divided ones? sorry for the derail.

 

[faster6.0]

dam gettin to those banjo's is a bitch!

90 fittings ftw!

 

[FX4 F2-Fifty]

there ya go!! you getting divided ones? sorry for the derail.

lets just say we will have very similar setups. and no problem on the derail.

90 fittings ftw!

this, but there on the back of the heads and i have hard lines already there, so they will stay for now. Unless the problem persists after next week.

I liked it better when i wasnt aware of this problem. Ignorance is bliss.

On a side note i forgot to add that there is no drop in FP when hooked to the regulator at WOT.

 

[mgeistman]

lets just say we will have very similar setups. and no problem on the derail.



this, but there on the back of the heads and i have hard lines already there, so they will stay for now. Unless the problem persists after next week.

I liked it better when i wasnt aware of this problem. Ignorance is bliss.

On a side note i forgot to add that there is no drop in FP when hooked to the regulator at WOT.

i bet not with a 100 psi in the heads!!
btw secerets about mods dont make friends!!LOL

 

[HeavyAssault]

What is the configuration of your fuel system??

 

[Twan]

Is your Regulator after the heads?
What psi is your pump?
If your pump is set at 100psi, then it will push 100psi till it hits the regulator, which is after the heads right?

 

[FX4 F2-Fifty]

What is the configuration of your fuel system??

well from the pump on, Aeromotive a1000---2 mic cat filter----fuel block(pressure reading)---90 fittings to the front of the heads----banjos without the check valve on the back of the heads----aeromotive regulator(pressure reading)----return to tank.

I can be more specific if need be.

 

[FX4 F2-Fifty]

Is your Regulator after the heads?
What psi is your pump?
If your pump is set at 100psi, then it will push 100psi till it hits the regulator, which is after the heads right?

Its not a regulated pump, im running an Aeromotive A1000 with the regulator set at 55psi. this should mean that all the fuel between the pump and regulator should be at 55psi no matter what, all excess should be sent back to the tank. The problem is that the pressure is higher before the regulator. The regulator is doing its job, its just that there is a restriction before the regulator i believe. I cant think of any other way for this to happen. If the regulator was bad it would read higher psi at the regulator. If the return was plugged or too small it would read higher at the regulator. I can set the Regulator to 20psi and it is still 100psi before the heads.

Thanks for all the help everybody, these are the problems i hate. I have never had the FP gauge hooked up before the heads, so im not sure if this has been going on for the past 3 years or not. But i WILL get it solved...eventually. Cant be good for the injectors, nor the pump.

 

[Twan]

Think of it like a air compressor, the tank has 150psi, then regulator is set at 100psi for the nail gun. The regulator is there to keep the pressure after it controed, not before. I'm sure that is a 100 psi pump, so it will put out 100psi all the time, as long as it can flow that much.

 

[FX4 F2-Fifty]

Think of it like a air compressor, the tank has 150psi, then regulator is set at 100psi for the nail gun. The regulator is there to keep the pressure after it controed, not before. I'm sure that is a 100 psi pump, so it will put out 100psi all the time, as long as it can flow that much.

Totally different i believe. the regulator holds that psi between the pump and regulator and sends the excess back to the tank. If there was no regulator there would be very little pressure (in theory) because it would just flow through the heads and back to the tank. Think of a garden hose without a sprayer. There is little pressure, high volume. hope this makes sense. Think if the regulator on the air compressor bled off excess pressure to the atmosphere, it would never build more pressure unless there was a restriction. Which I believe is what is happening in my case.

Sent from my DROID BIONIC using Tapatalk 2

 

[Twan]

Not really, on old cars we always put the regulator before the carb, we run 14 psi pumps, with less gpm to, if you have a 100 psi and say 160 gph pump, it's going to flow 160 gph or 100 psi right? Now I don't know the math to see what size hose it takes to keep 160 gph at 100 psi, so if anyone dose please help. And look at all stock stock setups, they regulate before the heads.
Has anyone with a setup like yours checked there pressure before the regulator, what are there findings?
This is all based on the fuel systems from gas powered cars, but we are talking about a pump, so I would think it was the same, on a big block we have, I needed two fuel pressure gauges, one for the pump pressure, to make sure it was good and one for the regulator, I had a 14 psi pump and 5 psi set for the carb, my pump was bad, had 6 psi at best, so ever time we bit the gas it dropped to 3, put a new pump on and it holds 14 psi till it hits my regulator then 5psi after, with 3/8 line.
I could be wrong too, wouldnt be the first time.

 

[09stroker]

It seems like it's basically a restriction at the heads (90degree fittings) causing the pressure to build before the regulator can control it.