I've been dealing with the right bank richer than the left by 0.8 AFR. Ruled out exhaust or intake leaks. Finally pulled the injectors, Deka 4 60lb. to FIC for flow testing. I scribed the cylinder number in them when I pulled them, so that is how the chart is labeled. They are not very consistant(4.4% spread)-however if I add totals from left bank (odd numbered) and compare to right bank (even numbers) it's not far off. I also noticed that after driving it for a couple hours and doing VE learns and get the VE tables looking good/then take it out next day-same CTS and IAT but just starting a drive then the VE tables are all over the place until it's driven for a couple hours again, then VE tables are back. Checked and confirmed they are real Dekas, not the counterfeits. I'm leaning torwards just getting new flow matched injectors from FIC, and if all the left bank were the lower flowing and right bank higher flowing it would be a simple decision. Although the difference between starting out driving vs after a couple hours is really making me question these injectors. I would really appreciate everyone's thoughts.

 

If you didn't have the data to show the 0.8 AFR difference in AFR, would it make a difference?

RBob.

 

I believe that by tuning VE tables by the left bank, (nattow band) then the commanded AFR is set by the left bank-then the right bank shows as richer-so is diminishing the ability to tune by the wideband (in the right bank) for PE and under boost. I don't want to end up lean under boost in a cylinder and melt a piston.

 

Then tune so that the leaner bank is rich enough, done.

Threads like this go under the split BLM mess. Here's a question, do both banks have the same exact compression ratio? Exactly the same air flow into the chambers?

See the issue, OTOH, do we need NASCAR precision?

RBob.

 

Did you ever swap the injector banks from side to side like I suggested in your other thread?

 

No, I didn't, I figured if I'm going to the effort to pull them out I would just go ahead and get them tested. Another odd thing I noticed and don't know if there is any significance to it-2 of the injectors flowed a little less after cleaning.

 

Maybe a dumb question, but is the tuning memory faulty or not keeping power when car is off? Like a radio has the constant 12 volt memory wire?

 

It's a diagnostic step to verify if the problem is the injectors or something else. What if you swapped sides and the problem didn't change?

 

Yes, I was being lazy-not wanting to pull the super ram etc.twice.It's on me. I was just hoping the injector test would make the problem/solution apparent. I'm going ahead and getting the FIC 650cc injectors (flow matched within 1%) and will update once it's back together. I'm just at a loss as to why the VE table will change so much after it's been run a couple hours vs. after just warmed up with same CTS and IATs. I can't help but suspect something is going on with the Deka 4s, or at least with a couple of them. I looked them over and am pretty sure they are not the counterfeits that I've heard of. They all ohm at 12.4.

 

On my 7730 ECM I found some coolant temperature coefficients... (my "quasi closed loop thread). I'm not sure exactly what they do or how they work, but they really seemed to enhance the consistency of how the car runs from day to day, cold to hot, etc. Not sure if there's something similar in the EBL.

It also had the effect of locking my BLMS to 128 (although the Integrator still bounces around as usual). I already had my BLMs nailed down so locking to 128 wasn't a big deal in my mind.

 

Time for an update on injector problems. I pulled the Dekas and now have FIC 60lb injectors in it. Noticable differences. The idle surge that would come and go is gone. Idles and responds to small throttle inputs noticibly smoother. The rpm surging that came when the fans turned on is gone.
There is still a discrepancy between wide band to narrow band but much less now.
Tuning using VE learns are way more consistent from session to session. I raised the VE learn RPM threshold for closed loop so as to hit more areas. I have to run closed loop for smog so prefer to tune closed loop.
Now a question on the shepe of the VE tables. I know the old adage of give it what it wants, but I've never run into VE tables with these shapes. Also posting is the last VE Llearn showing it's down to minimal changes now.
Thoughts on these tables-the shapes? Also what does it mean when it says overflow on the ve learn?

 

Not much help with your questions. But when you say you moved the VE Learn RPM Threshold. Where is that? Are you using EBL P4 or Flash?

Also, I assume because you are doing closed loop tuning your WOT areas are lower due to entering PE? Seems weird to me looking at a Low Speed VE table with the high area where it's at on yours. Mine is all highest on the 100 Kpa side of the graph.

 

BLM-RPM learn threshold in EBL P4. My PE is set up to 90map and 80 tps so should not be effecting up to there.

 

Okay yep I remember that now...been so long since I've done any kind of closed loop tuning I couldn't remember.

 

That is perfectly normal. I never tune until engine is fully warmed up. I drive 15-30 minutes before tuning. With '7730 style, if the MAT is under the plenum, good luck getting consistency with VE tables. Also, even if "IAC" is same, air temperature, barometric pressure and humidity will make VE tables vary.

Here's my 4 tuning states:

Test A: Cold - bias
Test B: Ops - Stable
Test C: Heat Soaked - bias
Test D: Ops after heat soaked - Stable

Word of advice. Don't pay too much attention to VE tables variations (unless it's over the top). You are trying to be accurate with an antiquated inaccurate system.

 

Yes. Recommend to remove the MAT sensor from the plenum, get a IAT sensor from a LT1 Camaro/Corvette and put it in the air duct. Then if the EBL a table for airflow vs air temperature impact to fueling calculations (like the 7730 8D INV MAT table), then disable that. The 8D, it allows you to tell the ECM to use or ignore that table.

That really helped in the consistency department for me.