Fuel pressure/supply problem

TY162

New member
Well, I'm having a fuel pressure or supply problem. Here's the history. I had a starting problem. Sometimes it wouldn't start on first cranking attempt. 2nd cranking attemp would fire right up. Then at various times it would nose over while accelerating. Then fp(stock) died. I replaced it with a Walbro 255. Starting problems dissappeared (short lived) but then started doing it again. Then would run out of fuel while driving. hooked up a fp tester and watched it (sticking out of the cowl hood) while driving. Fp would drop from 39 all the way down to 18 and anywhere in between. Put on a Kirban afpr. 39lbs at idle (with vac) 43 without. With a slight free rev in park it will increase to 43 when vac. reaches 0. While driving (not dependent on boost, just accelleration) pressure will hold for awhile (it will seldom increase with boost)then drop steadly. (Pump SOUNDS fine while idling although seems to be Really spinning btw.) When pressure drops and it bogs out while driving I can cycle the ignition (coasting in N) off and restart and pressure is back! for a little while. When it drops I can cycle the ignition quickly and its ok again for a short time. Also when it doesn't start I don't have any fp and the pump is either not on or very quiet. When I turn the key again (sometimes twice)pressure will come up and it starts fine. These are all problems common between the stock regulator and the Kirban. The pump is running on the stock wiring. Could the pump be bad? It only has about 150 miles on it. When I replaced the pump I flushed the tank, the lines and put on a new filter. I tried a new relay also. The only codes it throws is 44 lean, (yeah?.. no sh#t :mad: lol. I have a matco determinator and for as little as I know how to use it, everything seams ok.. no knock problems, spark retard, map etc. Would a leak between the pump and the sending unit cause this. Doesn't seem to be affected by fuel level.Why does cycling the ignition power affect it? I'm at a loss. Any ideas on where to trouble shoot? Sorry for the long post but just want as much info out there as I can. Thanks,
Scott
 
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Icarus-54

Donating Old Member
Re: Fuel pressure/supply problem

It is possible to be leaking in the tank.I had the same thing happen to my sy a couple years back,the center strap broke between the pump and pulsator.
 

TNPhoon

1of28
Re: Fuel pressure/supply problem

I'm not as schooled as most of these guys.
But recently when we dropped my tank to replace the fuel pump, also noticed that there was some wear in the sending unit lines on the top of the tank that some fuel was seeping out of FWIW.
 

TY162

New member
Re: Fuel pressure/supply problem

Yeah, I'm prob going to drop the tank again :( and double check every thing for poss. leaks. It's the ignition cycling that is throwing me.
Tonight I went to start it. ..Ign. on- faint pump sound,6 psi., pump turns off
Ign. off/on louder sound of pump, 20 psi., pump turns off
Ign. off/on strong pump sound (like I think it should, like its under a little load instead of free wheeling)42psi, pump turns off. Starts good.
Went to move it again, ign. on ..no pressure no pump sound. Crank engine, then it starts to slowly build pressure, engine fires when it reaches about 30psi then maintains 39 psi at idle.
 

ty166

Donating Member
Re: Fuel pressure/supply problem

are your ground connections at the tank clean and tight ??
 

TY162

New member
Re: Fuel pressure/supply problem

Problem is fixed. The new Walbro 255 pump was bad. Replaced it with an Airtex E3625S. It's pushing 62 psi under boost :)
 

turboten

low budget big dreams
Re: Fuel pressure/supply problem

yeah im having the same problem. 3 walbros in 1000 miles. its the relief on the top of the pump. they were all real ones too. unless summit sells bogus stuff now:2cents:
 

Flyin Ryan

hated cuz he drives fords
Re: Fuel pressure/supply problem

oh haha I was wondering because I remember seeing another thread a few weeks back of someone tossing one in his typhoon over a walbro
 

turboten

low budget big dreams
Re: Fuel pressure/supply problem


I paid $130.00 each for a pair of 255's from Summit last year. I specifically asked if they were "Genuine". Upon receipt of them I tested them as per this video. They sounded like the "cheap toy drill". So I sent them back and vowed to never purchase from the lairs and importers of cheap Chinee Crap at Summit ever again.

RAT BASTARDS! who sells the real walbros anymore. two was sold under the Grenatelli motorsports name and the other had Edelbrock packaging.. both were just repackaged and marked up "walbro 255" pumps. well thats maybe what they want you to think. my apologies for high jacking .im sick of pulling the bed every week. just got on a rant i guess:rant:
 
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Re: Fuel pressure/supply problem

RAT BASTARDS! who sells the real walbros anymore. two was sold under the Grenatelli motorsports name and the other had Edelbrock packaging.. both were just repackaged and marked up "walbro 255" pumps. well thats maybe what they want you to think. my apologies for high jacking .im sick of pulling the bed every week. just got on a rant i guess:rant:

Ron Gregory at www.apeusa.com He's been with the syty community for quite a while. They offer a few products for sytys. Phil Chivers propshaft and driveshaft loops, hood prop rod elimination kits, ic pumps, and other stuff.
 
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