Lean codes mystery - O2s replaced, no vac leak, MAF okay

[seventyfive]

Was it just the o-ring or was the injector cracked at the bottom?

All the lower o rings are leaking...and the inside of the truck smells like a beer fart.

 

[discostew]

P.T. asked about miles and state of tune. The truck is at ~150,000 miles. The owner's son installed new plugs and Magnacores a few years and maybe 35K miles ago. No misfire codes, and the truck seems to run well and strong otherwise. The O2s he's used are all Bosch 15175s from Advance. And yes, the connectors are clean.

Injector-related solutions are an interesting idea, but would there not likely be other discernible drivability issues if it were a fueling problem?

Again, please, have any of you seen situations where the ECM was the problem, and can any DII 4.6 SAI ECM be installed and work fine w/o Testbook or other programming?

Thanks.

I've seen reprogramming fix some goofy fuel trim stuff but I find it hard to believe the ECM itself could cause that without there being some really big issues . I would be checking the grounds , and looking for ac current bleeding out of your alternator field terminal . That would mess up every pulse width modulated signal on the truck . When checking the grounds remember that when the truck is running true ground is the alternator case / key on engine off true ground is the neg. battery post.

 

[discostew]

Also check the locating tabs on the air box lid / not the ones that clamp it down , the ones that locate the top over the bottom of the air box . Or just switch your air box over to his truck . Have yopu reset adaptions ? These trucks are to stupid to know you put a different mass air meter on it for a while .

 

[jymmiejamz]

Also check the locating tabs on the air box lid / not the ones that clamp it down , the ones that locate the top over the bottom of the air box . Or just switch your air box over to his truck . Have yopu reset adaptions ? These trucks are to stupid to know you put a different mass air meter on it for a while .

A broken air box lid would not cause lean faults, although it can cause the mass air flow meter to fail which can cause lean faults.

 

[discostew]

A broken air box lid would not cause lean faults, although it can cause the mass air flow meter to fail which can cause lean faults.

I know it doesn't make sense if you follow logic and the basics of unmetered air . But we have fixed a few like that , back when we were working on lots of discos . My foreman reminded me about it . He said he's got another truck to try a known good one .