17:1 air/fuel ratio

17:1 air/fuel ratio

Postby raj4851 » July 26th, 2020, 8:00 pm

I have a 355 sbc with a Comp 248@.050, .525 lift cam, 2 500 Edelbrocks on a tunnel ram. I put an a/f ratio gauge on it several years ago. It ran roughly 14.8 at 3000 rpm. I've had trouble with fuel pressure fluctuation problems intermittantly. I have a Mallory 140 pump with a Mallory 4309 regulator. I was driving it the other day and I noticed that a/f was 17.0. The fuel pressure had dropped to about three pounds. I got it home and began to adjust the fuel pressure up. I didn't spend a lot of time because of time restrictions. I have a Fram cartridge filter before the pump & have changed the element, even though it didn't need changing. I have a fuel pressure gauge at the regulator & on the cowl. They seem to be registering about the same pressure. It would appear that I need to rebuild the fuel pump but I don't understand the lean condition. By the way, if I open my cutouts, it goes to 17.0. Any ideas? Thanks in advance, Rod

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