hi guys,

my fuel trims keep running negative. They seem to have become increasingly worse.
for a long time they were happy with my injector scaling. Recently I have upped the scaling twice and the trims have now dropped below -12.5.

Is there an issue I need to correct?

running tephra 706, 660 injectors. p0170 (which is a result of the trims?)

thanks

 

changed stations lately?

Local gas went from more ethanol added to less?

 

boost leak?

 

I'm sure the gas has switched to summer blend. Not supposed to be a change in ethanol/10%.

Will keep bumping the injector scale up.// this would be a good diagnosis if a station had a overload of ethanol in their gas.- I would think. Though this migration of trims has been escalating for several tanks, different stations.

Not feeling a leak weakness, and it has affected the idle trims too, so its got to be something more than a air leak. I did bump the idle screw several weeks ago to help a big cam idle issue.

no new hardware in the last six- plus months.

 

misread your post...deleted my comment

O2 sensor, ethanol change, boost leak are my guesses.