fuel pressure

[yankeedoodoo]

Last weeks trip to the dyno showed fuel pressure @ idle @ 56, which I thought we had set @ 42. Under hard acceration runs it dropped to around 37. Should this be happening? And. if not, what might some things to check to fix (stabilize) the fuel pressure? Could this situation be causing any additional problems? Thank you very much for all thoughts and suggestions!!

[John Howe]

Assuming your pressure regulator is 100% OK then IMHO the drop in pressure you are suggesting is from a fuel pump that is under capacity for your stage of tune

 

JH

Deliveries by Saffron, the 222bhp yellow Sausage delivery machine

[AMMO]

Yankeedoodoo

 

Your fuel pressure should be rock solid. If it fluctuates you have a problem. The high pressure at tickover could be a restriction on the return line. As an experiment take a hose from the regulator and run it into to a container or Jerry can, making sure you have plenty of fuel in the tank (and that you aren't smoking!). If the fuel pressure at tickover stays at the preset level then your problem is in the return line. Possibly the bore of hose too small.

 

The lack of pressure when fuel requirement is high may be due to a lack of capacity of the pump or other problem. If your fuel pressure fluctuated inconsistently the engine would be very difficult to map.

 

Looks like you are going back to basics to sort your problem out. That's good.

 

AMMO

[yankeedoodoo]

Gents, Thank you very much for your excellent suggestions. I think the dyno operator should have mentioned that a session with less than steady fuel pressure was not going to be very productive!

[yankeedoodoo]

Gents, Thank you very much for your excellent suggestions. I think the dyno operator should have mentioned that a session with less than steady fuel pressure was not going to be very productive!

[yankeedoodoo]

OOppps, one less pint last night and I'd be a litle less shaky on the left key............

[murph7355]

My fuel pressure is in the 50s, but does fluctuate which I thought very odd.

 

Then I wiggled a wire on the sender and lo, it fluctuated.

 

Tested with a more reliable gauge it seemed steady, no amount of firming the connectors up seemed to cure the other one so I've decided to live with it as is.