Fuel injection pressures and controls.....

[mrvette]

Got an interesting shituation here, added DPFI to my '72 vette 355 engine, so years ago I noticed the engine would stumble when tank was lo, have tried many solutions......but noted recently some relatively new ones....

SO it has to do with flow rate and MAP regulated Fuel Pressure valve on engine....L98 style.....and of course its got a vacuum signal to it...

SO I note the fuel system has a return line to the tank, and I wonder why, as it occurs to me the RATE of fuel delivery to the engine that is about 80% returned to the tank, unused....

SO the question is, to install a far better fuel pump/routing/supply system where the return to the tank is basically eliminated.....

any new cars do that?? or still stuck with the same crap from designs years ago??

I thinking one way fuel flow, so the fuel RATE of circulation is greatly reduced, and simplifying the damn plumbing issues......

[Mr.Bigg]

I would look at your fuel cap first might just be to much vacuum in the tank as it nears empty.

[snide]

If your gas gauge is working, fill it up when it gets to half a tank. You're welcome.

[Old Ben]

Originally Posted by Mr.Bigg

I would look at your fuel cap first might just be to much vacuum in the tank as it nears empty.

Could be.

[mrvette]

Originally Posted by Mr.Bigg

I would look at your fuel cap first might just be to much vacuum in the tank as it nears empty.

Thanks but that was first up, many years ago....locking breather cap....


but the vacuum operated fume recovery system from tank forward to the charcoal canister is failed in the open position, I routed it to the above throttle blades...so 'ported' vacuum

[Mr.Bigg]

Originally Posted by mrvette

Thanks but that was first up, many years ago....locking breather cap....


but the vacuum operated fume recovery system from tank forward to the charcoal canister is failed in the open position, I routed it to the above throttle blades...so 'ported' vacuum

I have also seen some that had pressure in the tank when you open the tank. What years are you working with? What size injectors and fuel pressure?

[mrvette]

Originally Posted by Mr.Bigg

I have also seen some that had pressure in the tank when you open the tank. What years are you working with? What size injectors and fuel pressure?

Basically an L98 engine, L98 heads, LT1 induction with HEI up top in back, no EGR just the old PCV setup......22-24 lbs injectors 35 lbs pressure, adjustable regulator...L98 style......I used the stock 3/8 fuel line to supply and the stock smaller line for return......it's a speed density computer 1227730, saves all that air induction crap/plumbing MAF......aftermarket chips of course....'72 convertible vette.......

[Mr.Bigg]

Originally Posted by mrvette

Basically an L98 engine, L98 heads, LT1 induction with HEI up top in back, no EGR just the old PCV setup......22-24 lbs injectors 35 lbs pressure, adjustable regulator...L98 style......I used the stock 3/8 fuel line to supply and the stock smaller line for return......it's a speed density computer 1227730, saves all that air induction crap/plumbing MAF......aftermarket chips of course....'72 convertible vette.......

I think you might be a bit light on the fuel pressure.

[MrPeabody]

What the hell do you people think this is, a car forum?