01boydws6

iTrader: (19)

Ok so I installed a second 255 walbro today with a T fitting and I am using a hobbs switch to activate the second pump. I now have less fuel pressure at idle than before, my fuel pressure guage does not hold pressure when I turn the key and prime the pump as it did before and when the car is running I have less pressure on the guage wtf!!! The hobbs switch is set for 6psi and is wired sepereate through a relay and to the battery. I tested to make sure the hobb switch was working by putting 6psi of pressure to it from the air compressor and it turned on. Fuel pressure was 62psi before the second pump was installed and when would rip on it fuel pressure would drop to 56 or 58 psi. Now fuel pressure while running is 58psi and drops to 40psi as soon as I get in to boost. What did I do wrong? I did not cut the bottom out of my bucket but I did remove the venturi system and the small rubber plug in the bottom of the bucket. Am I sucking the bucket dry??

rocket5979

iTrader: (1)

It sounds like the check valve in the second pump may not be working and allowing pressure to bleed off through the pump when it is not running.

LS6 Silverado

iTrader: (27)

Need a Y fitting. The T fitting will not flow properly, especially when your second pump turns on. They end up fighting each other when both pumps are on. NOS sells them in-6 (6an) and -8 (8an) Kinda spendy tho. Hope this helps...

Lonnies Performance

iTrader: (16)

The t-fitting has nothing to do with idle pressure (unless it leaks). Low idle pressure is the best indication of an internal leak.

Though possible, after years of using Walbro pumps I have yet to have a check valve failure.

Check into your hose selection & assembly methods & you will likely find your problem.

01boydws6

iTrader: (19)

thanks Lonnie I was thinking that could be my problem but wanted some input from the experts.

01boydws6

iTrader: (19)

does not having the venturi system or not having the bottom of my bucket cut out hurt me at all?

NoGamesLS1

iTrader: (16)

Not a problem unless it is bullheaded.

01boydws6

iTrader: (19)

Well I pulled the tank back out last night and swapped out the flexable line I cut up from my racetronix pumps, I thought that clamping over the ridges was causing the fuel to leak past the t fitting. I also swapped the t fitting out for a y fitting and used SAE30R10 line I have the top of the y almost right against the fitting that goes out the top of the bucket head, I clamped at the top of that fitting with a hose clamp and then clamped to the y then ran a line down to each pump. The pumps sit right against the bottom of the bucket. I put everything back together and still the same issue. Could I have a bad regulator or pump?

jomomma

iTrader: (39)

hopefully, its not yyour fuel guage!

01boydws6

iTrader: (19)

I thought about the gauge too..

01boydws6

iTrader: (19)

well I spent the $100 on a new electronic sending unit and still have the same problem. I thought for sure this was it because I put a guage in place of the sending unit and had 60psi at idle and when I put 6psi of air from the air compressor to my hobbs switch my pressure went up to 65psi at idle. So I installed the sending unit last night it shows my 60psi at idle but when I get in to boost the guage still drops and drops fast I am going to pull the tank out again tomorrow and swap out the 2nd pump to see if that fixes the problem... any opinions?

Schwanke Engines

iTrader: (1)

Are you sure it is a Walbro 255hp pump? Where did you buy it? How much was it? Make sure of that first.

01boydws6

iTrader: (19)

yes both are walbro 255's, the primary pump I bought the racetronix pump and hot wire kit from Lonnie, the second racetronix I bought from a member on tech. I have another walbro pump my buddy gave me it is a walbro gs342..that is the one I was going to try