Fuel Pressure Question

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dhondagini

Junior Member
Heres the deal.
I recently swapped a b16asir2 into a 93 civic.
I was planning on forced induction, but time ran out before college, adn now so has the $.
This was a swap into a car that was also being completely redone and ofcourse little things kept comming up in the end, such as the fuel pump going.

I had installed a Aerospeed Fuel regulator and gauge (the kind that modifies the stock unit, not a whole new one)

When the pump went, I thought, why not just get a walbro 255, so I did. well, now the fuel pressure is like 53psi and flames are comming out of the exhaust.
As cool as that may be, I know I cannot run this.

-The fuel regulator won't go down any lower and we even swapped a stock regulator and that only gets it to 50 psi.

-I also have a Apexi Vafc

My question is, how can I get the psi down in a cost effective way. Will the vafc change this drastic ratio, is there a better regulator I can get that will actually decrease the psi or should I get a different fuel pump, if so which one?

:wacko::doh: :feedback:

Also if getting a stock fuel pump is the key, I will swap anyone who has a stock pump with reasonable miles on it for free as long as the person pays for shipping both ways. My pump has like 30 miles on it.
 
Well, you could install a pressure reduction valve, an adjustable regulator, a pressure switch to turn off your pump, replace your pump with a less efficient one.

I thought that your pump should turn off at a specified pressure. Otherwise the same thing would happen at an idle in every Honda(too much pressure), unless Honda makes a pump that won't build enough pressure to cause that.
Be careful not to confuse volume with pressure. You want a high volume of fuel when your car needs it, but supplying 150 psi through a pinhole won't do it. I'm sure you know that but many people don't.

It is a possibility that your old pump wasn't turning off soon enough and burned itself up. Consequently, if you added a new pump it would do the same thing until you find the culprit. Just a thought.
 
- I have the adjustable regulator, but it won'd adjust any lower than 53.

-Where can I find a pressure reduction valve? what exactly does it do?

-The pressure switch, is that a relay near the fusebox or something that may be bad? is this something I can buy incase the pump isn't turning off, where can I get a good one?

I am trying not to have to get a new pump because a honda pump is like $170 - $200 and I just bought the walbro and would like to keep it, the buying a new pump would be a lst resort.

thanks
 
Originally posted by tab@Sep 25 2003, 12:22 AM
Well, you could install a pressure reduction valve, an adjustable regulator, a pressure switch to turn off your pump, replace your pump with a less efficient one.

I thought that your pump should turn off at a specified pressure. Otherwise the same thing would happen at an idle in every Honda(too much pressure), unless Honda makes a pump that won't build enough pressure to cause that.
Be careful not to confuse volume with pressure. You want a high volume of fuel when your car needs it, but supplying 150 psi through a pinhole won't do it. I'm sure you know that but many people don't.

It is a possibility that your old pump wasn't turning off soon enough and burned itself up. Consequently, if you added a new pump it would do the same thing until you find the culprit. Just a thought.
Click to expand...

What do you mean "a pressure reduction valve?"

What would be the purpose of a pressure switch to turn off the pump?

Fuel pumps dont keep pumping higher and higher pressures when they are receiving voltage- They are either on or off, and when they are on thats as much fuel as they will pump without increasing the voltage

Otherwise the same thing would happen at an idle in every Honda(too much pressure
Click to expand...


The fuel pressure regulator allows for this, when you open the throttle the diaphraghm closes and increases the pressure..it lowers the pressure at idle

It is a possibility that your old pump wasn't turning off soon enough and burned itself up
Click to expand...


Once again- If the fuel pump was turning off when the motor is running, it would shut off due to lack of fuel.

replace your pump with a less efficient one.
Click to expand...


highly unnecessary, as the pressure can be modified quite easily at the fuel rail

check out endyns site for a how to on drilling the stock fpr diaphragm to lower pressure by sending more fuel back to teh tank
 
Explanation.
I work at my local water dept. We have very powerful pump stations in places that make so much pressure that they will literally blow the plumbing apart inside the walls of a house. Many of those people with inferior plumbing use pressure reduction valves. I won't pretend to know how they work, but they do work. Much like a regulator it sounds like. I searched summitracing.com before my post, and they have them for fords and stuff. I just placed it out there as an option.

To keep a system at full pressure, it is not necessary to make the pump run all the time. Stored Kinetic Energy I believe is the term. If the pressure were to drop to a certain point, the pump could come back on to preserve the set pressure. I didn't know that Honda pumps stayed running all the time, or that they bypassed through the regulator back to the tank.

So you're suggestion is to make the return line larger in order to allow the system to run at a lower pressure. Wish I would have known that before my post. :worthy:
 
Originally posted by SolReaver@Sep 25 2003, 08:15 PM

Fuel pumps dont keep pumping higher and higher pressures when they are receiving voltage- They are either on or off, and when they are on thats as much fuel as they will pump without increasing the voltage
Click to expand...

not true pumps will pump more fuel as you add voltage up to the 15.4 volt mark where most pumps crap out on newer vehicles pumps are called rising rate where the fuel pressure is controlled by changing voltage
 
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