my fuel pump died...walboro 255gph hp.... got a new holley who makes walboro and got thier 255 gph hp... basically the pump for forced induction 4cyl... now the car runs richer then before... the car has standalone and was tuned 2 1/2 years ago... i replaced my pump last year and it never ran richer or any different.... i could see that a new pump flows a little better then a dirty pump but y would it run rich now if i didnt for the last year when i replaced the other pump... car is also running a little lean while crusing... i always have had the car set to run lean when driving but now its more lean and more rich at idle.... any ideas?

 

your o2 sensor is goin bad sir...

 

how does the 02 sensor explain this? car was tuned on a wideband regardless of the o2 sensor... how would a bad o2 affect it... i had a few go bad before and i only got a check engine light without any fuel problems... any help would be greatly appreciated

 

ur o2 has nothin to do with it, that pump is a little stronger now cause the old pump was giving out thats all, so u can retune now cause 2 years it might need to be tunned again. and usually good ems dont need to read the o2's anyways.

 

y do i see a difference now when i changed the pump a year ago? the car didnt need to be retuned then...