High fuel trims

[crenche]

Hello all. Haven't posted in for.
I have 2017 Escalade ESV.
I had a injector failure on #6. So I bought all new /used injectors.
When removing the bank 2 fuel rail #6 and #8 injectors were stuck in the head. Tried everything to remove them but had to eventually remove the head and punch them out from the other side. Replaced head gaskets. New high pressure fuel lines. New exhaust manifold donut and gasket. New head bolts. New intake manifold gaskets. From this point on I'm getting terrible gas mileage. My long term fuel trims on bank 2 range from 25 to 30%. Bank one is 17%.
I have smoked the intake and exhaust. No obvious leaks seen.
What am I missing?
Fuel pump starts at 62 then will dwindle down to 42 over about 5 min or so.
Do you think a weak fuel pump would cause such a bad fuel trims?
I can't figure this out.
I did replace the MAF sensor and no changes to fuel trims
Anyone have any other ideas?
Thanks everyone.

 

[Coveman]

What brand of injectors did you get? A friend replaced injectors (off brand) as PM and was delighted when his computer told him he was getting crazy good mileage afterwards, but his fuel trim changed and it threw some codes. I asked him to check the mileage the old fashioned way and it turned out to be worse than before. Put the old injectors back in and the codes and trim corrected themselves. Parts these days are a crap shoot

 

[crenche]

What brand of injectors did you get? A friend replaced injectors (off brand) as PM and was delighted when his computer told him he was getting crazy good mileage afterwards, but his fuel trim changed and it threw some codes. I asked him to check the mileage the old fashioned way and it turned out to be worse than before. Put the old injectors back in and the codes and trim corrected themselves. Parts these days are a crap shoot

They were supposed to be used OEM off of Amazon. They had the QR code on them. Looking back at the listing they may have been non OEM. I did test the resistance of all of them before installing them. Don't know the flow.
I guess i could change back to the old ones and replace with 2 new OEM.
What do you think about fuel pressure? Does the computer decrease the pressure if not needed?

 

[Coveman]

I didn’t see mention of any codes, what if any did it throw?

So many bad part stories on injectors out there, besides real gm oem parts I saw a guy that liked GP Sorenson from AutoZone.

This attachment might be interesting to you as well

 

[crenche]

Codes
P0097 intake air temp sensors 2 circuit low voltage
P00F4 intake air humidity sensor circuit low voltage
P0102 MAF sensor low frequency (i just changed this with OEM)
P0174 fuel trim system lean bank 2
P2227 barometer sensor performance
P2228 barometer sensor low voltage

 

[crenche]

I figured it out. I took off the injectors and found that the seal had not correctly seated and rode up the shaft so there was lack of sealing on cylinders 6 and 8. This was sucking air in causing positive fuel trims.
I bought new seals and the seating tool and it fixed the problem. I also used a metal brush to clean the orifice in the head which was corroded.

Now my fuel trims have gone negative. To -6. Not sure why. Im hoping my high pressure fuel pump isn't going bad.

 

[Fless]

If you haven't run it very long it's probably still burning off excess fuel vapors and doesn't need fuel added. Depending on how long it ran with high positive fuel trims, an oil change might help that out. But generally -- on any given bank -- the sum of the LT and ST trims should be within -10 to +10%. Really good trim sums are -5 to +5%.