Fuel pressure and tuning

[racinreaper]

I pulled the fuel pressure gauge up to the cowl today so I could see it and make sure my FP reg was working... made a few runs and watched it and my A/F ratio gauge... Fuel press was up to 58-60 at wot and 15 lbs boost. A/F gauge was showing rich at wot.. what I need to know is if these numbers are inline with everyone else's.. I had thought about turning the fuel pressure down to get the A/F gauge showing green. I believe the truck is running rich because it seems to be a little sluggish at times.. and at idle it blows black soot out the tailpipe onto the floor. Would turning the fp reg down a little ( its set correct with vac off and plugged.) a little more help lean it out and run better. or should I just leave it alone. I had thought about turning it down then running it and watch the A/F gauge to see if it changes... from what I have read on here,, rich will hamper preformance as much as lean. Am I right or am I backing up. Let me know.

 

[SeattleSy#1255]

Re: Fuel pressure and tuning

well, what is your base set FP right now?

i'd keep it rich untill you know its to rich and you know its running ok. Safer that way, just for the time being.

 

[TYTILIDIE]

Re: Fuel pressure and tuning

I would back it down. Is the truck stock? If so, it needs to be between 38 and 40. I would back it down maybe 2 p.s.i. at a time til you get it right.

Mike

 

[dgoodhue]

Re: Fuel pressure and tuning

I pulled the fuel pressure gauge up to the cowl today so I could see it and make sure my FP reg was working... made a few runs and watched it and my A/F ratio gauge... Fuel press was up to 58-60 at wot and 15 lbs boost.

58-60 at 15psi is around 43-45psi base, which around what stock is. Don't worry about the stupid a/f ratio unless its a wide band. The rich part is when you driving around normal, under WOT it supsoed to be rich. If it feels slugglish, you probably want to buy or hook up with someone with a scan tool.

 

[racinreaper]

Re: Fuel pressure and tuning

I do have a datamaster but I haven't really had the time to learn how to use it correctly.. Is there a parameter on it that I can watch to see what the A/F ratio is.