fuelpress issues

[dirtdemon]

ok, after all - i found out that the fuelpressure falls down under load , instead of rising w/boost :rant:

so, could a fawked fuelpump cause that, what else could have happend ...
... is a bad AFPR an option, all 6 injectors are ticking :squint:

swapped the pump 2 times (1st when installing , 2nd when tank+sending-unit was changed) in and out -

btw.: pump is a 255lph walbro, 2 years old, around 10k mls at work - is it possible that the pump could be dead after that short term of time ?

TIA, pat.

 

[bezerk]

Re: fuelpress issues

swap map sensor and FPR. both are cheap

 

[Don W.]

Re: fuelpress issues

MAP sensor has nothing to do with FP. (In a direct manner anyway.) Make sure that the line to the the FPR is good, no leaks, connected correctly.

 

[#2875]

Re: fuelpress issues

afpr gets my vote. do you have the stock one you can put back in temporarily and check if it does the same thing?

 

[Andreas]

Re: fuelpress issues

Check Vacuum hose to the AFPR

 

[dirtdemon]

Re: fuelpress issues

first of all, thx for ya headnuts guys :tup:

no fuel out of AFPR w/o vacline
vacline = brandnew and silicone

what do you think of my theory :
- @ idle everythings fine - fuelpress = 45psi w/o vac and ~37psi w/ vacline attached
- under load / boost (gear : N) : fuelpress goes down to 20psi

what i'm thinking of :
pump delivers barely enough fuel for idle (pressure) and "too little" fuel running back in tank via AFPR - when more fuel is needed (eg. under boost) the pump isn't able to deliver the volume ...
... and i can't recognize this, because i only can read the pressure but not the volume the pump makes

am i thinking the right way :dunno:

TIA, pat.

 

[Don W.]

Re: fuelpress issues

Well you're not going to get boost in neutral. Forgetting that for a moment, if FP goes down as you rev in neutral then change fuel filter. Why nobody, including me, said it before is beyond me. :squint: Anyway change fuel filter, check again. Fuel pressure still goes down while you rev in neutral? If FPR is adjustable then you might take it apart, keeping close track on what goes where, and see if something's in there. Otherwise, gonna have to check that FP. IMHO If you check the FP check that the pressure dampener is removed. Looks like a miniature master cyl. Eliminate it with hose made for being submerged in gasoline and use mini screw clamps.

Let us know what you find out.

 

[dirtdemon]

Re: fuelpress issues

Don W.,

first thing it did, was change the fuelfilter, and knocked it around just to see if derbis coming out - nothing (kinda lil rust from the fuellines seem pretty normal )

but sadly nothing changed w/ the new FF swapped in ... :squint:

so, thats why i think right on the FP ... btw. sounded different since the tank has been swapped - that's the point since the problms came up ...

and : the sound of the FP doesn't change while reving the engine -

IMO there's the possibility that the FP has been running dry 1 time too often (and took a damage) while changing the tank ... :roll:

checked the fuelpump and all its connections visually ... but looked quit normal - only thing i can imagine is that the FP is fawked inside :rant:

ordered a new FP from mike lee ... will see what i can find out :dunno:

regards, pat.

 

[dirtdemon]

Re: fuelpress issues

update :

new FP is in and probs seem to be solved - in the end it was a fawked fuelpump :rant:

anyways, life's beautiful :turbo: *gg*

reg, pat.