speedo

iTrader: (15)

Kinda been stuggling with this pump since I have put it in a year ago. On start ups I have to crank it over... turn the key off, then crank it again and then the fuel pressure with rise and it will start. Other than that it works fine once running and will hold pressure at WOT. It doesn't hold the pressure on the gauge once I turn it off like the stock pump did.

Today I was messing around with some other stuff and turned on the ignition but didn't start the car and for the first time heard fuel running back into the tank as the gauge on the pillar dropped. I shot a 30 sec video which I will post below. You can actually hear the gas running back into the tank...

Bad fuel pump check valve or air getting into the fuel line?

When I shot this vid I just turned the key on and then after the dinging if you listen close you can hear the fuel running back into the tank as the pressure drops.

Just click on the pic...

andereck

Does you car fail to start? You have pressure it seems as soon as the key is turned. Its a non-issue.

dynocar

It can be an issue, if you turn off the key and lose fuel pressure quickly with a warm engine, the fuel will boil and turn to vapor in the hot fuel rails. This can cause a hard start condition and lean running until all the vapors are purged out. I consider fuel pumps and regulators that do not maintain fuel pressure for at least 20 minutes after engine turn off, junk.

andereck

Then you consider pretty much any aftermarket high volume pump and regulator that wasn't an OE adaptation junk then and you're certainly entitled.

onfire

iTrader: (17)

Have you tried just cycling the key 3 or 4 times to let the pressure build up before you crank it? I had the exact same problem....check valve was bad in the Walbro.

speedo

iTrader: (15)

Nope it drops no matter how many times I key it. When I heard the fuel actually going back in the tank I figured check valve but was thinking maybe I pinched a fuel line just enough to where it was letting air in the system.

Think they will warrenty that thing yet...


Thanks for the info....

JoeyGC5

iTrader: (24)

I had the same problem with Racetronix and my Vette. The problem turned out to be a clogged check valve in the factory fuel line to the rail. Talk about a pain to buy/replace.

MECHAM

iTrader: (4)

bad pump...or you got a hose leak


check for hose leak...

assuming you have the access panel cut.

fill up the car...remove the bolts from the fuel assembly..pull the assembly out until you can see the sock..have some1 turn the car on...if you dont see gas gush out from the hose...

bad pumper...

speedo

iTrader: (15)

Acess panel whats that... I get so much $hit from my freind about that panel, but heck I had to use it twice already because I got the wrong parts with my kit the first time...

Anyway thanks for the info maybe I will try it this weekend...

dynocar

No, a good 700+ HP pump such as Accel/DFI's 74702 (Bosch pump originally used in high HP turbo Porsches), that can be used internally or externally and their 74567 high flow regulator is one example of maintaining such high standards that I require (no junk). If more fuel volume is required, staging such pumps works well because of the internal check valve that prevents fuel feed back. I'm sure that there are advertisers on this forum that handle such products, no, I am not affiliated with Accel/DFI.

andereck

You made my point. (Bosch pump originally used in high HP turbo Porsches)
The mallory (accel) regulator is not designed to hold pressure at shut down either.

Your fuel check valve is most likely now in your fuel system. Hopefully in the filter that you have installed after the pump. This is common from a walbro type pump. There is a reason that check valves aren't initially incorporated into aftermarket performance high volume fuel pumps. They make the unit longer becuase you must design them not to adversely affect the performance of the pump. With a high flowing regulator not holding pressure due to their bell-less design its not considered important to put the check into the pump as an assembly. You can always install one for parallel setups.

dynocar

Quote, "You made my point. (Bosch pump originally used in high HP turbo Porsches)
The mallory (accel) regulator is not designed to hold pressure at shut down either."

Accel/DFI (Bosch) pump - proven quality and reliability in high HP applications, Accel regulator - whether it's designed to or not, it does hold pressure at shut down.

For the majority of performance applications, why install a system that requires adding check valves when we can accomplish the same thing with them already built in or worse yet, not using check valves at all? Besides hard starts, which this thread is about, boiling fuel can leave bad residues in injectors.