Upgraded fuel pump opinions for SE's
05-29-07, 07:58 PM
#1
Audio Cronic Syndrome
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Upgraded fuel pump opinions for SE's
So I've noticed for a while a gradual loss in power in my rebuilt S5/S4/ported engine in my SE and have pinpointed down to fuel...I knew my fuel pump was cavitating a little but today I pressure tested my system....32 psi at idle and it spikes for a moment up to 36 when revved but goes back to 28 psi...NOT GOOD! I'm supposed to be around 75 psi....
SOOOO..I was thinking the universal Walbaro 255 GPH I think..but does it pump out 75+ psi???? What kinda pump would everyone suggest?
SOOOO..I was thinking the universal Walbaro 255 GPH I think..but does it pump out 75+ psi???? What kinda pump would everyone suggest?
05-29-07, 08:06 PM
#2
Rotary Enthusiast
Check all filters/screens first:
1.) Drop the tank, and remove and clean/replace the sock on the fuel pickup.
2.) Pull the fuel pump, and carefully extract and clean that little screen on the pump inlet.
3.) Replace the main fuel filter.
Then re-check fuel pressure following FSM procedure. You should see around 40 psi with engine off/pump running, down in the 20's with engine at idle, and jumping back up towards 40 when the throttle is snapped open. The 75 psi value you quote is when dead-heading the pump against the pressure gauge, and is NOT a running fuel pressure value.
1.) Drop the tank, and remove and clean/replace the sock on the fuel pickup.
2.) Pull the fuel pump, and carefully extract and clean that little screen on the pump inlet.
3.) Replace the main fuel filter.
Then re-check fuel pressure following FSM procedure. You should see around 40 psi with engine off/pump running, down in the 20's with engine at idle, and jumping back up towards 40 when the throttle is snapped open. The 75 psi value you quote is when dead-heading the pump against the pressure gauge, and is NOT a running fuel pressure value.
05-29-07, 08:18 PM
#3
Check the above mentioned items 1st. As odd as it may sound, the stock SE pump flows more gph than the stock TII pump and, if iirc, more than the the 255 lph Walbro. That's one reason why the SEs have the largest diameter supply and return fuel lines of any FI 7. If everythig checks out and there isn't any blockage, the Walbro will supply a 2nd gen TII to over 300 hp and is a cheaper replacement than the stock unit.
05-29-07, 08:37 PM
#4
Audio Cronic Syndrome
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hmmm....eventually EVERY problem will be solved in this car..I'm not discouraged though. I'll always have a rotary. I might just step it up to a FD soon...
07-08-07, 02:20 PM
#5
Audio Cronic Syndrome
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so I finally checked the fuel inlet screen or lack of. Its supposed to be inside the inlet side of the fuel pump if you pull off the hose? I did that and there was nothing there...need some insight.
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07-09-07, 06:15 PM
#11
75 psi..... never!!! I know the manual said that, but both my gsl-se's have a msd fuel pump and it doesn't reach that. Both the gsl-se turbo and the gsl-se with the s4 t2 motor.
Not enough fuel would cause your car to bog anyway....
with my msd I still get more or less the readings you got,
what you need to do is get a air/fuel ratio meter, not the autometer guage that does nothing but a real monitor, to see if your are too rich or too lean. I am running the innovative motorsports meter, 14.7 is the ratio you should be reaching for.
Not enough fuel would cause your car to bog anyway....
with my msd I still get more or less the readings you got,
what you need to do is get a air/fuel ratio meter, not the autometer guage that does nothing but a real monitor, to see if your are too rich or too lean. I am running the innovative motorsports meter, 14.7 is the ratio you should be reaching for.
07-09-07, 07:13 PM
#12
Audio Cronic Syndrome
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its definitely bogging...
just the thought of trying to get that fuel filler 23 year old rubber off the tank makes me cringe... o well has to be done.
just the thought of trying to get that fuel filler 23 year old rubber off the tank makes me cringe... o well has to be done.
07-12-07, 07:47 AM
#13
yes change that fuel filter, its actually not that hard... Thats the first step, then if your injectors have never been removed and sent for cleaning, I really suggest that. They need to have a certain spray pattern, if clogged and dirty it just drips into the cumbustion chamber....
big loss in performance.
big loss in performance.
08-26-07, 05:31 PM
#14
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I was this close to buying an OEM fuel pump from my work (yes I work at Mazda) when I took the time to find the specs on the output of the stock fuel pump...1700cc/min or more...this when calculated comes out to 102 LPH if anyone wanted to know. I'm going with the Walbro 155 or maybe 255 for future upgrades. Will have to also purchase an aftermarket regulator and hook it up almost attached to the fuel pump. A lot of them come with guages now so even easier to diagnose in the future.
08-26-07, 07:11 PM
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Walbro fuel pumps... the the 255 will be too much for the stock se fuel system, but they do make a 190 which better suits the stock EFI.
Here is a site that has a kit which will offer the proper fittings for your application.
http://autoperformanceengineering.co.../ext_pump.html
GSL391 is the pump im refering too...
here is some info. of tte walbros 255 compared to the 190.
http://www.roadraceengineering.com/f...pflowrates.htm
cheerz,
vern
Here is a site that has a kit which will offer the proper fittings for your application.
http://autoperformanceengineering.co.../ext_pump.html
GSL391 is the pump im refering too...
here is some info. of tte walbros 255 compared to the 190.
http://www.roadraceengineering.com/f...pflowrates.htm
cheerz,
vern
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