hey guys...im having some fuel pressure issues. its abit flakey on idle, sometimes its at 35 psi sometimes 38 sometimes 40 sometimes 44.its on a stock reg with double pumper(walbro 255s) anyone seen this before? maybe have a clue where to look?

 

You having any drivability issues? Running lean/rich etc?

 

its on open loop to see whats going on. it does lean out or go rich depending on pressure....but no divability issues tho

 

Are you running both pumps full-time? Or Hobbs switch?

 

its on a hobbs switch sir

 

I purchased 4, yes 4, modded Walbro 255s of which 2 failed within 100-200 KMs, the other 2 were brand new and weren't pushing fuel out of the tank to begin with.

It would be more convenient and easier to narrow down where the issue lies if you have a fuel filter such as this one:

http://www.foreinnovations.com/product_p/16-900.htm

Having this with the pressure gauge would help identify if the severe pressure fluctuation is being caused upstream or downstream.

Now this will obviously aid in analyzing the issue, but most of us are just tired of spending more money.... I would suggest firstly checking everything again, then swap places of both pumps, i.e ignition pump gets installed to the hobbs switch and vice versa.

Check your fuel filter, possible clogging could cause fluctuations as well.

If all hope is lot, try an aftermarket fuel regulator + fuel rail.

 

yeh that would be handy but alot of $$....swapping pumps is a really good idea as it will take 5 mins....thanks for the sugestion! ill give it a go

 

Tried swapping ignition pump and no change..... Gotta be the reg playing up yeh?

 

That would be the most likely suspect.