I have a miss match of the AFR's when the engine is warming up. The cAFR is around 13.6, but the wide band reads on average 1.5-2 AFR lower until the engine is warmed up. Is there a way to correct this and make the actual AFR come in line withe what is being commanded? Also, I have been wondering about transport delays. How do I know when I have found the correct transport delay? And on that note, when I do a VE Learn from the BLM's, my commanded AFR is 14.2, but the learn reports that the VE is spot on when the actual AFR is about 13.8. Is there a way to fix this as well?

 

Not on a cold engine. Although, usually the reported AFR is leaner then the commanded AFR. On a cold engine the burn isn't as good. I go by how well the engine runs, not what the WB reported value is.

When the INT cooperates.

There may be a voltage offset or something isn't set up correctly. At the same time, in closed loop the ECM doesn't target the stoich AFR, it targets the values in the O2 window tables.

RBob.

 

Thanks. I wont worry about the miss match during start up (which I forgot to say is lean at first, but then within 30 seconds or so reads rich). As for the other two, I will try different values and see what it wants. I will mess around with the injector voltage offset and the O2 window values.

 

regarding this: "There may be a voltage offset or something isn't set up correctly." I was referring to the WB set up.It is best to run any WB controller grounds to the engine block. Running them to the chassis can cause voltage offsets, which skews the reading.

RBob.

 

Something else I hadn't realized. Fortunately, my ZT-2 is grounded to the block.
Dumb luck?

 

I have it grounded to the Intake Manifold. Should I move to the block its self? I have other grounds connected on other parts of the intake.

 

Mine is on the plenum. Works fine.

 

Need to be careful grounding to aluminum. It can oxide over and create a high resistance. I have a ground stud on an aluminum intake. After a good cleaning with emery cloth anti-seize was used on that area of contact.

RBob.

 

RBob,

I pull my plenum off often enough that it doesn't oxidize.

 

I've been trying to offset to lean it out. Went way lean on voltage offsets to try to see a difference and just can't.
Attached is the bin and a datalog of it. This is with the AC Delco narrowband you recommended. (That definitely made the commanded vs wide band a lot closer.) And the TT1 is grounded to the engine. Left the tt1 at 14.7 as stioch so expecting to see 14.1 read out with the 10% here.
If you can find what I am missing it would help my sanity!
Thanks, Pete.

 

Not sure if the TT-1 is the same setup as other Wide Band Lambda contollers? If it is your spot on.

The controller measures Stoich of the fuel in Lambda. Like you said E10 fuel 14.12 to 1 AFR. It then converts Lambda to AFR for the human. If the Wide Band is set to 14.7? Then when it is reading Stoich 1.0. converted to AFR 14.7. The true AFR it is displaying is not accurate, but it is.

 

I understand that part now, however with that bin used I was trying out making it run lean. The O2 values are skewed very lean-however it still corrects back. Other folk say they've bee able to adjust and have it hold leaner or richer with those tables, but I can't get it too and figure I must be missing another table somewhere.

 

In Closed Loop it will always adjust back. There's only so far you can tweak O2 sensor values.

Try open loop.

 

Actually the p4 ebl is supposed to be able to do that in closed loop as I understand what RBob has posted before.

RBob-your thoughts?