So at idle my fuel pressure is at 3-4 psi on a rx-1. I tried adjusting the Malpassi fuel pressure regulator, but no matter how much I turned the adjusting screw in or out my fuel pressure won't change. I checked this with two different fuel pressure gauges. Shouldn't I be able to adjust my fuel pressure up or down fairly easy? My wideband is showing good a/f's so I don't know if it's a big deal anyway.
Also which way of turning the adjusting screw is up in the fuel pressure, and which way is down? I assume out turns the fp up and in should turn it down.
Also which way of turning the adjusting screw is up in the fuel pressure, and which way is down? I assume out turns the fp up and in should turn it down.
zross1 said:So at idle my fuel pressure is at 3-4 psi. I tried adjusting the Malpassi fuel pressure regulator, but no matter how much I turned the adjusting screw in or out my fuel pressure won't change. I checked this with two different fuel pressure gauges. Shouldn't I be able to adjust my fuel pressure up or down fairly easy? My wideband is showing good a/f's so I don't know if it's a big deal anyway.
Also which way of turning the adjusting screw is up in the fuel pressure, and which way is down? I assume out turns the fp up and in should turn it down.
Back off the jam nut and tightening the set screw will increase base fuel pressure. If you are doing this and not seeing an increase you either:
Have a bad regulator
Are picking up the fuel pressure signal from the wrong spot
Where did you tap in for FP?
I'm picking up fp from the bottom outlet hose from the fuel pressure regulator.
You need to check before the reg coming from the fuel pump
The bottom is the return line if I remember correctly. You need to tap the side where two lines come from the regulator and go to the carbs.
Brain fart
, between the reg and the carbs

Thanks guys, got it figured out. I just didn't turn the adjustment screw in enough the first time.
ultimate
Extreme
- Joined
- May 14, 2005
- Messages
- 73
- Reaction score
- 0
- Points
- 806
- Location
- ,Quebec
- Website
- uniklabels.com
- Country
- Canada
- Snowmobile
- Yamaha apex
the MALPASSI regulator with boost application work fine if you change the spring in.
it was the problem that i got with this reg, but now work fine!
bye
it was the problem that i got with this reg, but now work fine!
bye
Similar threads
- Replies
- 12
- Views
- 4K
- Replies
- 13
- Views
- 3K
- Replies
- 4
- Views
- 862
- Replies
- 12
- Views
- 5K
-
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.