Fuel pressure problem after installing Racetronix double pumper..

[THE BLACK MAMBA]

I just install a 510 lph Racetronix double pumper last night, then after first start up i notice my fuel pressure was a 45 so i tried to adjust it down but i couldnt.....so today i drop the tank to see if any of my rubber hose was kinked then check out the pump to see if i damaged it during install....every thing is ok...so to double check my theory of kinked lines i left the tank down and fired it up...same results... high fuel pressure and when i rev the engine the pressure drops to 40 then back up to 45....I even switch out the jumpers to control either pumps...samething. when i put both jumpers in the fuel pressure jumps to 100... I`m tired of quessing before i damage something...any help or ideas ? Thanks Mike

 

[trbojo]

so is this set up so that one pump runs constant and the second kicks in under boost?

 

[THE BLACK MAMBA]

yes...the other pump is hooked up to the control jumper from the harness...fuel pressure was fine with the old setup

 

[T- Type Tim]

return line too small for volume you are moving now?

 

[pacecarta]

make sure you dont have both pumps running at idle , if you connected the hobbs to the led lead and left the pump connector with the jumper it will run both pumps, the fact that you say its 45 and then you can get 100psi swapping the connectors makes it a return line issue

if the filters for the pump are positioned under the return tube that the pumps mount to you could have blocked the return inside the tank. also make sure that you didnt connect the return line to the vent tube

 

[trbojo]

just a side note....I have an issue with a friends car who just had a walbro 255 installed a few weeks ago with high pressure problems......I have one on my car that's 6 months old and failed.....now this guy.....cant be that many people installing pumps wrong

 

[pacecarta]

so your complaint now is the pumps flow too much

 

[THE BLACK MAMBA]

make sure you dont have both pumps running at idle , if you connected the hobbs to the led lead and left the pump connector with the jumper it will run both pumps, the fact that you say its 45 and then you can get 100psi swapping the connectors makes it a return line issue

if the filters for the pump are positioned under the return tube that the pumps mount to you could have blocked the return inside the tank. also make sure that you didnt connect the return line to the vent tube

Since the tank is still down, i will check the filters

 

[trbojo]

so your complaint now is the pumps flow too much

not my complaint....yet. I haven't installed mine yet. but here's 2 people right off the bat, without doing a search of recent threads that have high pressure issues after installing new 255 pumps. starting to notice a pattern...there have been KNOWN issues with walbro pumps in the past....

 

[trbojo]

http://www.turbobuick.com/forums/threads/walbro-fuel-pump-died-again.377265/ look at post #6 from racetronix. it states that they modify the bypass valve because they know our application will be used at "higher than normal pressures"... one could take that as the pump not really being adequate for our cars....

 

[trbojo]

and I'm not trying to slam anyone in all this...just pointing out that there have been problems in the past, and it appears they may be resurfacing again. my particular issue was, with the second to last pump, it would hit about 60 psi then start fluttering and drop off. that pump was about a year old. now this pump, 6 months old, hits about 65-70 psi, and drops then start fluttering wildly from 70-80. my target fp should be about 75-77 depending on where I have my base set and boost (28-30 psi). we noticed in my logs that my idc was way high and that's when I noticed I wasn't getting stable fuel pressure. if the bypass valve is being modified, could it now be causing a high pressure issue with these newer pumps?

 

[pacecarta]

no , pressure is a direct result of the return not of the pumps ability to build to a higher pressure before the spring gives to protect the pump from overpressure
pressure does not mean flow , and pumps tend to flow less as pressure increases
run anything harder than its intended purpose and its life will be shortened

to get more flow you need to either increase the voltage or lessen the restriction before the rail

 

[THE BLACK MAMBA]

My gauge is fluttering and dropping pressure when revving the engine...I`ve got a video, but for some reason i cant post it

 

[trbojo]

same exact thing my buddies car with the high pressure issue is doing....really starting to look like there's a new issue...we'll know for sure after I get mine in, hopefully tomorrow.out of curiosity, where did you purchase the pumps?

 

[THE BLACK MAMBA]

Full Throttle...

 

[Eric Stage I]

This is a fuel return problem, not a pump problem.

 

[QWKRTNU]

You need to switch your return line. Use the vent line for return and the old return line as a vent line. The vent line is bigger than the return line.

 

[trbojo]

You need to switch your return line. Use the vent line for return and the old return line as a vent line. The vent line is bigger than the return line.

Has this been done before? Where would you make the switch.. Up front, or just at the sender? If you did it up front you'd obviously have to change fittings, flare lines etc....

Posted from the TurboBuick.Com mobile app

 

[T- Type Tim]

Swap them both then adjust the pressure down

 

[QWKRTNU]

Yes it has been done. You do it uo front and at the sender. I cut the fuel hose up front and hose clamped it to the vent and changed it on the sender. It's the cheapest and fastest way not to run a new line.