2G Rich AFRs

[98gstJames]

So my old fuel pump went out and would cause my engine to sputter and act all sorts of wack when I was trying to drive. It already had a Walbro 255 pump in it and so I replaced it with a new Walbro 255 pump.

My car doesn’t sputter or anything now but my AFRs were running super lean under acceleration. That was a bleed off issue from the o-ring on the pump not seating correctly into the hanger. Got that issue fixed and it no longer is lean.

It’s still a little off now though, at idle I’m sitting at about 12.8-13 on my wideband. I haven’t taken it on a drive yet to see what it’ll do but I’m just wondering what changed my AFRs if all I did was change the pump. Could the old pump have been on its way out and when it was tuned it needed to be turned up?

Also if needed I can post a log from ECMLink, TIA

 

[steve]

Best if you posted that idle log so we can see if it's in closed loop when you're checking the wideband or if something else is going on.

 

[dwb]

Verify your base fuel pressure and the vacuum/boost source for your fuel pressure regulator.

 

[98gstJames]

Here's the log for when my car is idling

 

[Stapl3]

Zero out the mafcomp sliders. Turn in the BISS screw.