I need help once again. I have a Blueprint 400, miniram with a 7730 ecm. My narrowband is not matching the wideband, but only at certain map limits. At 20-30 I'm getting 13-1, 30-50 it's around 15 as it should be. 50-70 the wideband is around 18-22. And above 80 it looks good again 14-16. I've been playing around with Loop closed param slow o2 r/l map and the fasto2 r/l. I haven't drastically changed those figures. Would this be on the right track or is there a better way to get the wideband and nb to match?

 

Is your NB on the same side of the engine as the WB?

 

Different sides NB on driver, wb on the other.

 

I would check for any mechanical issues with either bank first, perhaps eliminate a few things from the equation like spark plug and fuel injector flaws, leaky header gaskets, and check for slightly cracked/arcing wires. Anything that would cause a slight skew in the O2 readings. If all is well, and if you can relocate the wideband to the y-pipe (if equipped) so that it can read and average out both banks that would get you closer to the final conclusion. If the O2 readings stay exactly the same way using the y-pipe location it could just be a calibration issue, but if the O2 readings suddenly become synonymous with one another throughout... then I would soon set my sights on the miniram being the culprit as far as air distribution.

- Rob

 

yeah... since the NB only monitors half the engine, one malfunctioning cylinder can drag down both sides of the engine.

Also keep in mind that with the WB on the opposite side, you'll often see the WB showing the ECM's reaction to R/L conditions on the NB side.

For example, if the NB side runs rich momentarily (but not the WB side), the ECM will lean out the entire engine to compensate, so you may see a momentary lean spike on the WB side. This is not necessarily an indication of "Split BLM's".

Miniram's are notorious for low speed/low rpm fuel distribution issues.

 

Thanks for the replies. The WB is below the header connection to the y-pipe and before the Y. I've checked for leaks and it looks ok. If there was a leak I would think that the wb would always read leaner especially at lower map numbers 20-40. It seems to do the opposite though which would make me think of a prom problem.

I did change the o2 r/l more drastically and it didn't change anything might have even made it worse. I put a new NB sensor and will adjust my tables to the new figures Maybe that will be enough.

 

You might want to check out my thread on "Quasi Closed Loop".

https://www.thirdgen.org/forums/diy-...osed-loop.html

As I've said in other threads, it feels like it transformed the 7730 from an emissions/mass-production oriented ECM into a performance ECM. I've never had it respond to tuning the way it's doing now.

Before doing this, I used to have the AFR's drifting into 15-16 range on the WB (which is also on the opposite side as the NB). I had tried everything before... VE tables, R/L thresholds, etc... but nothing really worked.

But now, the AFRs stay pretty firmly planted between 14.5 and 13.5, depending on load, during non-WOT operation. In fact I was able to reduce my O2 R/L thresholds from a range of .600 to .750 down to .500 to .600. So ironically I get more power and better fuel economy.