right now i just finished a swap. i have an H22a4 with a stock regulator / rail and a walboro 255lph in tank pump.

according to my gauge (autometer electric) im sitting at 55-62 psi

stock i should be at about 36 psi or so.

I pulled a code 90 (fuel / evap system leak) and am wondering if that could be it. in the morning i will be swapping pumps to see if that does anything.

 

The Walbro is overwhelming the stock FPR - it can't return the excess fuel back to the tank, so pressure goes up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">The Walbro is overwhelming the stock FPR - it can't return the excess fuel back to the tank, so pressure goes up.</TD></TR></TABLE>

why wouldnt it have done this in the last thousand miles?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">The Walbro is overwhelming the stock FPR - it can't return the excess fuel back to the tank, so pressure goes up.</TD></TR></TABLE>

How come the fuel isn't returned back? Is it just with the 255 lph or does this happen with the 110 lph?

 

i checked all of the lines since i dont have the pump with me like i thought. there was a vacuum line going from the TB to a solenoid thats hooked to the evap can. the TB is a B16a3 (i think... its a del sol SiR TB) so the vacuum nipple is tiny in comparison to the H22 TB. the line was loose. i put a different hose clamp on her and reset the ECU. cel hasnt come back yet but we will see.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HondaBullSQ &raquo;</TD></TR><TR><TD CLASS="quote">How come the fuel isn't returned back? Is it just with the 255 lph or does this happen with the 110 lph?</TD></TR></TABLE>

The orfice in the stock FPR isn't big enough to flow the excess volume created by the new pump - so pressure goes up. I dunno if it happens with the 110lph, but on the majority of B and D series, installing a 255lph cause the fuel pressure to rise.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Shakes &raquo;</TD></TR><TR><TD CLASS="quote">why wouldnt it have done this in the last thousand miles?</TD></TR></TABLE>

Dunno about that - but if the vacuum reference to the FPR isn't good, as you've indicated it wasn't, this will cause fuel pressure to rise.

So your increase in fuel pressure just came on all of a sudden? I mean, your fuel pressure was spot on after the install of the new pump and then 1000 miles later you've got higher fuel pressure?

 

no, the old engine had the AEM FPR and rail. with that i ran at 40 psi which is what i wanted.

once i swapped engines i still had the walboro in tank pump but now a stock rail and regulator. once i got the engine to turn over for the first time it was at 50 psi at idle, up to 60 at WOT.

there is also a hissing sound but i feel that is due to the walboro over powering the stock regulator. once i get to my new place in cali i will change them over.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Shakes &raquo;</TD></TR><TR><TD CLASS="quote">why wouldnt it have done this in the last thousand miles?</TD></TR></TABLE>

So my original answer is correct then - IF you're using a stock FPR with a higher-than-stock volume pump, you will more than likely overwhelm the FPR which = higher fuel pressure which is your particular case here. You made the scenario sound a little different with your '1000 mile' reply.

Slap the AEM rail and FPR on this engine and be done with this 'problem'.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">
Slap the AEM rail and FPR on this engine and be done with this 'problem'. </TD></TR></TABLE>

not that easy at the moment though. engine is in san diego, im in austin. but soon enough hopefully.