He is talking about BLM locker being able to lock the wot reference blm to 128. It does not learn at wot the wot tables are affected by the last known blm before wot condition was engaged.

That is nice and all, but it only helps wot tuning be consistent. What we really need is a way to select when we want open loop activated so that it's only during cruise maps and rpms. Isn't there some kind of way to trick the computer so that it looks at the open loop afr tables only in cell 6??

 

there are be some a 2d tables to enable PE mode. once you reach the PE mode enable RPM the PCM goes open loop and it uses the afr10x table and the pe vs rpm and pe vs temp multipliers for fuel.

 

if your offering to write a code patch to make it so then be my guest. I got into looking at doing this some time ago. More headache then its worth. Just run the car openloop full time and fuel mileage won't suffer in the least. if you run it in open loop the WOT blm etc will all be non factors. And the car will generally run better. you can give it the exact AF it wants at any particular load. this will make the engine run tons better.

 

There is no AFR table in LT1 Edit. Does anyone know of an equivalent table in it (not where I can look at it right now)?

I could have sworn there was a way to limit BLM's in certain ranges with a software upgrade, maybe I should do a search on it to bring some of that stuff back up.

I wish someone could clear up the truth about how and when the PE vs RPM table is used (whether closed loop or open loop, either one). Any mainstream tuners who wish to chime in feel free

 

ok, did a search and http://web.camaross.com/forums/showt...ght=blm+locker post #8 says you can use the BLM locker to run PE mode (open loop basically?) up to say ~1200 rpm. Does this at least mean you can lock BLM's at 128 at whatever RPM's you choose? If so then I guess that may be of help albeit not ideal. I'm telling you there is something else though. I have read about people limiting fuel trims to 120 ....will search some more.

 

here it is. the pe vs rpm table is used anytime your in PE mode at WOT or not.as for the AFR table sounds like a flaw in the lt1 edit software.

 

Another way I have read about is to change the throttle % to enable pe at 1200-2000 rpm to zero % so when you are cruising in that range at light throttle you are in pe. You can adjust fuel in the wot tables because you are not going wot under 2000 rpm anyway. It was something like that... then something about setting limits on the blms so the comp doesn't try to do anything.

 

you can just set the min and max blm to 128 and accomplish the same thing. the integrator can only move the fuel trim about 5%

 

I was answering 96 ws6 who asked if the blm locker could specify rpm values of operation or something. I said no it could not, there are no user configurable parameters in it.[/quote]

I can send a copy if you want, post or pm me your email.

I don't know of any way to do that. You can of course set the max trim in the constants, but I don't know of any way to have different maxes for different map or rpm values.

 

I do have something in fuel that says "BLM = 128 at WOT, yes or no" ...I guess that's a way to lock the BLM? ...so I must have that feature already. How do you set the max trim? ...I might get by just fine doing that. I am interested in what 96 WS6 is saying too. CollinsAuto ....are you saying that even if min and max BLM are set to 128 it can still move around by 5% ?

 

yes i am saying it can move about 5% + or - unless the integrator is locked out.

 

I tried that WOT BLM locker program and it works perfectly. Everything is locked to 128 the second I go into PE mode. After working on the car this weekend I figured out that my car has an exhaust leak at the x pipe on the driver's side. I believe that is probably causing most of my surging at cruise problem and slightly split blms. Now the car runs like a beast at WOT but mediocre everywhere else.

Charlie, what is the original reason for you wanting open loop at cruise? Is there something in closed loop that you know for a fact is causing the surge? Could it be something physical or mechanical?

 

Cmahsaft overlap create high oxygen content in the exhuast at low engine speeds. the net effect of this is that the PCM is fooled into thinking the engine is leaner then it is. In many cases you do not want the idle to be at 14.7:1 you might actually want it alot leaner then that due to the camshaft overlap tossing oxygen down the header tube !

 

Interesting... I have been trying to understand what more overlap requires in terms of tuning. My cam is on a 115 lsa... should I use the VE tables or the MAF calibration tables to add fuel? First I want to get that exhaust leak I found this weekend fixed before I mess with anything.

 

you missed the point of my post. you might not want to have the Car at 14.7 idling. That might be excessivly rich in reality !