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2G Can a AFR gauge tell you if your over running your FPR?

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SaskTSI

Proven Member
54
4
Aug 17, 2019
St. Brieux, SK_Canada
So I was having some lean issues when i had the stock fuel pump in, I mean like wot I was at 12.3 or so, now I just finished throwing in a 255 not rewired, and no i dont have a afpr yet.. but my idle afrs seem to stay the same at around 14.7-15.5 kinda jumpy and at wot I'm now at the 10.4 range, how could I figure out if I am over running and what can be hurt?
 
I ran a 255 in a stock 1gb auto (390 injectors) and had no issues at all. You can use a afr gauge but it has to have a sensor to tell you the air fuels. You could also put an AUTO stock regulator on and it would bump the fp up by 5 lbs (if you could find one) richening up the mixture.
 
So I was having some lean issues when i had the stock fuel pump in, I mean like wot I was at 12.3 or so, now I just finished throwing in a 255 not rewired, and no i dont have a afpr yet.. but my idle afrs seem to stay the same at around 14.7-15.5 kinda jumpy and at wot I'm now at the 10.4 range, how could I figure out if I am over running and what can be hurt?

Overrunning the reg is more of a problem at idle than wot since fuel demand is lower. I had this problem on my old 95 talon after a 255 install it was running so rich at idle raw fuel was dripping out the exhaust. Drilling the siphon solved it.
Maybe you were out of pump with the stock unit and it's rich now that you have a pump that can keep up.
Still on stock injectors? Do you have link?
 
Last edited:
Cams in the motor???
Drops the hg so it won't pull the reg down.
Just wanted to ask.
 
Did you drill your siphon?

to answer your question, no your AFR (wideband) gauge can not directly tell you if you are over running your fuel pressure regulator.

to find out you will need a fuel pressure gauge or sensor, or a regulator with a gauge on it.

there are so many variables, do you have ecmlink? Post a log? Could be an issue with tuning that you are that rich at WOT

sounds just like you are rich from new fuel pump, and need either like you said, lower fuel pressure (with AFPR) or the tune leaned out in the top end
 
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