rex u.k

Hi all,
I have installed 1600cc injectors with appropriate supporting hardware and a supra pump(new), if i crank the engine or jumper the fuel pump via the diagnostics plug i am getting fuel pressure showing on the gauge fitted to the sx fpr.

My question is that should the fuel pressure hold after i stop cranking or should it go flat. Does the supra pump have a non- return valve which is supposed to maintain the pressure for some time or not?

The regulator seems to be working fine as i can adjust the pressure while cranking or using the jumper in the diagnostic plug.

As soon as i stop cranking the fuel pressure drops to zero immediately. Info appreciated

mad_7tist

it should hold pressure. are the injectors leaking down?

Sponge Bob Square Pants

It's interesting in the forum this thread show's 0 replies, but there already is one.
I agree, it should hold pressure.

rex u.k

Well i had the primaries out and ran a leak test and checked they were atomizing ok and checked them for volume at 40psi 12.5v.....all came up good.

The secondaries are brand new as is the pump and sx fpr.

I'm thinking that the pump does not have a non-return valve fitted, i mean the pressure drops to zero instantly after i stop pressurizing the system.

I'm sure the stock system holds pressure afterwards.It can only be going back through the pump so quick,if it were a leak i would have known by the rate it dissapears at.

Anyone have a supra pump fitted with a gauge could probably tell me if they have the same occurence?

mad_7tist

as a test pich the return line and see if it drops. then press the sys and pinch the feed. turn the pump off and see if it drops. then press the sys and pinch both , one befors your press gague, and see if the injectors leak down. but you are right it does sound like the check vavle. does it have a bit of a long first crank ?

rex u.k

It's not going back through the retun line because it holds pressure where i set it whilst cranking or via jumper wire in diagnos. plug.

Its going back through the feed line as soon as the cranking stops.

The stock system holds pressure via the fuel pulsation dampener, it is also a one way valve as well as a FPD, i no longer have this because of upgraded fuel set-up so no pressure hold.

Basically i wanted to know if the supra pump had a non- return valve.It appears it doesn't, either that or mine is screwed.Although my pump is brand new.

Yes the first crank is long,infact it's the only crank.......new rebuild, new housings and all that bollocks so its playing hard to start