Hi, I run an AMC 401 with Howell converted to EBL. It's the 350 version with 61#, 12 psi and VSS that was on my previous 360.

I've been reading about tuning the VE map and have some throttle body backfiring under load between 1000 to 1900. Only in closed loop.

So I'm doing some learn runs with Lean Cruise off. But I've been reading that tuning could/should be done in Open Loop and checking the AF ratio after. That's what the purpose of the EBL learn feature is right?

http://www.enginebasics.com/EFI%20Tu...Loop%20o2.html

So, if I understand during open loop, the ECM takes the value of the VE map as is since there is not O2 sensor feedback.

I am confused here?

Thanks

 

So you have no NB02 sensor and wish to use a WB in place of NB to do VE corrections ?

If so EBL allows that. Some say a faster learn as well as PE learn.

edit: NB learn is option as well.

 

yes, I have a narrowband. A WB would be great. I'm considering the WB kit from the EBL site in the future.

 

No, you are not confused. With the EBL can auto learn the VE tables via the long term fuel trims (BLM) while in closed loop. Note that WOT goes open loop so can't use the BLM method for WOT tuning.

For WOT tuning of the VE tables can use a WB and force the ECM to remain in open loop (set closed loop enable CTS high). With this method the EBL will learn in the WOT areas along with the normal areas of the VE table.

When starting out it is better to use closed loop anyway. As the short & long term fuel trims (INT & BLMs) will change to aid in drive-ability.

RBob.

 

Cool, I just sent you some money for the TT1 WB. All this reading about WB these last few weeks made me salivate. All this money into an engine, let's do it right I guess.

 

Noob question; is WOT when TPS is at 100% and only then?

 

Yes not to be confused with PE which can be involked generally >50%. I think cars are set around 70% and trucks higher %.