Why am I getting AFR spark correction at WOT when lean cruise is disabled? HPTuners help file says that this table is only active if lean cruise mode is enabled. I suppose there's a mislabeled table somewhere?
In editor it's labeled AFR spark advance correction. In the scanner it's labeled AFR advance.
2002 5.3 silverado
Last edited by Jason B; 08-29-2018 at 02:37 PM.
IMO (correct me if wrong thx)
AFR correction is just AFR correction it has nothing to do with lean cruise. Only that lean cruise happens to use it when commanding leaner than... 1
PE mode commander AFR richer than 1 so it uses that table
if anything else commands leaner/richer a/f ratios it might/should also use that table
So everything that HPTuners has written about the AFR spark correction table is wrong? Like in Editor itself? in the help files? All of that is misinformation?
Or is there some other table that I can't find thats adding spark at WOT?
its never been for lean cruise mode specifically. its only been based off of the commanded or recorded afr. so if it goes lean and hits a cell with a timing pull registered then yeah it will pull ignition. vice-a-versa for a cell with positive timing registered.
like 90% of the ecu's cant even have lean cruise mode as it requires the canadian ecu to work.
i am not sure what hpt wrote for the table definition but thats how its worked since i can remember.
Last edited by cobaltssoverbooster; 08-30-2018 at 11:27 AM.
2000 Ford Mustang - Top Sportsman
The description is not correct then right?
Attachment 82984
What do the top row of numbers represent on this table?
I'm getting 4 degrees AFR advance and nothing I calculate out is even close to these numbers.
Attachment 82985
why on earth would anyone advance timing when the afr gets richer
thats not how you tune an engine usually. Normally you start with some max number that it can possibly be and take away from that.
Who put those numbers to begin with? When you command 1.2 in PE mode it adds 4* of timing that is what it says- crazy talk of some steady state advance timing for a given a/f ratio
it should be more like, subtract 2* or 3* from whatever is possible total in the basemap
I'm guessing the GM engineers put the numbers there. It's the stock tune for a 2002 silverado. Wasn't me, ain't that some shit....Originally Posted by kingtal0n
Equivalence (EQ) Ratio (the inverse of Lambda).
The table is for spark correction based on EQ Ratio. Less than 1.00 is a leaner than stoich mixture (i.e. Lean Cruise), while greater than 1.00 is a richer than stoich mixture (i.e. Power Enrichment).
GM used this table sporadically it seems. In 2002 only trucks used it. In 2004 it was used by trucks and Corvettes.
Only Holden (Australian) operating systems had Lean Cruise enabled from the manufacturer.
I figured it must have been the OEM. they do things like that all the time- put strange means to some end that you normally wouldn't even think about it that way.
In the sense of making final corrections it could go either way, minus or plus timing, but if the computer still uses the final timing number to determine a torque then it doesn't matter how that advance got there.
Typically when things get richer, you are trying to protect the engine, which corresponds to less timing. intuitively. So setting it in reverse is just counter intuitive, if nothing else., kind of a reverse logic flow. I like my settings to all flow the same direction if that makes any sense.
its a two part description telling you that its going to make spark corrections based on commanded afr. then as a secondary it does so to aid in spark control during lean cruise mode.
for those of us in the US. its rarely active and the benefits are only verifiable via the dyno so for me i opt to disable this table so i dont get any interference from it at random times and wonder what happened.
2000 Ford Mustang - Top Sportsman
top axis defines commanded afr in values representing EQ Ratio. anything over 1 is rich and lower than 1 is lean with 1.00 being stoich.
Last edited by cobaltssoverbooster; 08-30-2018 at 11:26 AM. Reason: corrected information
2000 Ford Mustang - Top Sportsman
It cant be, I just used this graph to pull timing in my application with commanded a/f ratio over 1.00 (richer)
made a picture had a minute ;D
whatafradvdoes.jpg
Last edited by kingtal0n; 08-29-2018 at 08:52 PM.
Gentlemen, hopefully we have answered Jason’s original question / concern.
Threads often get derailed into side issues (which are also important), but may not assist the original poster of the thread.
HPT did not completely label the table in question, which means that the end user must make a logical inference.
If you check other tuning software, we will see that this table is labelled as EQ Ratio.
If you look at parameters in HPT involving:
Open Loop Fuel
Power Enrichment
Catalyst Protection
You will notice that these all reference EQ Ratio (not Lambda).
With the P01 and P59 PCMs (LS1-B for the EFILive crowd) GM used EQ Ratio as the underlying basis for fueling.
Thanks for the clarification everyone.
It can be useful in other ways... on later cals where BE is inside of the "main loop" and is functional, you can use it to add spark to a turbo car outside of boost or at lower boost areas as referenced to mixture. .... That way if you are making 2PSI and spooling up, you could have a 12.2:1 mixture and 21 (whatever) deg of spark instead of racing to the bottom on mixture and spark. You can feel it.
that would make sense why it was a negative value. back tracking the provided picture from King shows roughly -1.2 *
in other ecu's its been lambda but those ecu's i speak of had oem widebands so thats likely why im used to seeing something different. thanks for setting me straight.
2000 Ford Mustang - Top Sportsman
nobody is trying to set you straight. You are one of the most helpful and contributing members on this entire forum. 5D giraffe guy and you basically run this site. I wouldn't even post at all if I didn't think you could handle my antics because its my greatest wish you never stop trying to help.
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