$12 to $12p conversion

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Re: $12 to $12p conversion

Postby Matadore » Thu Jan 09, 2020 7:06 pm

thanks for your help guys. So im best to ignore the unknowns, copy over the rest of the tables and see what happens?

in the Nvram am I able to have one map the original $12 bin and the other $12p? or do I need to have both $12p...

also is it ok to have the original eeprom plugged into the nvram for limp mode with different software to the nvram?

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Re: $12 to $12p conversion

Postby antus » Fri Jan 10, 2020 11:30 pm

Well at the end of the day you need to get the right tune on the car. Many people start again when they dont know enough about the original tune, but you can try it and see if you are best off with some, none or all of those changes.

You can run 12p and 12 on the nvram, but you will need to stop the car and swap the map jumper then start it again when you do. You'll need to learn about stacking bins and make a 128kbyte image with the 2 tunes in the right spots and flash it on to the nvram chip with an eeprom programmer. You can leave the original memcal on the nvram for limp.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: $12 to $12p conversion

Postby Matadore » Sun Jan 12, 2020 10:50 pm

ive gone over the changes and made a list of the differences and where ive copied the data too. If any of you guys could please confirm im on the right track here? the first and last im unsure on...
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Re: $12 to $12p conversion

Postby antus » Mon Jan 13, 2020 2:57 pm

Yep your on the right track. The checksum is fine, dont copy that, let tunerpro update it to suit the cal data. The mask one if it is the right CEL number is also correct. Generally there are 2 flags as you are looking at. One is to process a code, one is to trigger the check engine light. In most cases you want to process it, but not illuminate the error light. This will allow the ECM to work around having some sensor missing, but it wont light the CEL (check engine light) as the car is in the state you expect it to be in. For other types of errors, eg when things are going out of factory range due to say, boost, you do just want to ignore it, so you would toggle the process code setting instead or as well.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: $12 to $12p conversion

Postby Matadore » Tue Jan 14, 2020 5:43 pm

Awesome thanks!

I’ll assume the intention was just to remove the CEL when the o2 sensor was sniffing the cam rich exhaust etc, I’ll untick the CEL code 45.

Going through some tables to get a better understanding. Couple of questions if someone can please explain...

“Map A: A/F ratio - cold engine A/F ratio vs coolant temp and map”
This table goes up to 104°, Is this table in use until the coolant temp reaches above 104° at which point it changes to “MAP A: A/F ratio - 20-100kpa air fuel ratio vs RPM and MAP”
Is this a target AFR regardless of RPM? Can this be cut down to only apply at lower temperatures, eg 80 and below?

“MAP A: A/F Ratio - initial Run A/F Ratio offset vs coolant temp”
Is this a timed table? As in does it only run for x seconds then changes to the above tables?
This table has all single digit entries, Can someone explain that? Are they subtracted from the AFR tables above?

Is there more info about integrating a wide band sensor into the Delco? I see the analog input is D8 on the delco. How can I determine that ecu is using the wideband sensor and not the factory narrow sensor?

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Re: $12 to $12p conversion

Postby antus » Tue Jan 14, 2020 7:56 pm

the pcm always uses the narrowband, the wideband is just in the logs for your tuning on the pc. When its not connected there will just be static data there. You usually want to put target AFR and wideband AFR on the same monitor so you can compare. Probably with map and rpm (and anything else you need to monitor at the same time) on the other one.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: $12 to $12p conversion

Postby delcowizzid » Tue Jan 14, 2020 9:35 pm

It will use the cold engine a/f table upto the max temp for cold a/f setting in the scalers list probably around 28 or 40 degrees or there abouts if I remember rightly have a look. Initial run offset is added onto commanded a/f table and is decayed out by number of crank reference pulses over time
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Re: $12 to $12p conversion

Postby Matadore » Fri Jan 17, 2020 1:53 pm

antus wrote:the pcm always uses the narrowband, the wideband is just in the logs for your tuning on the pc. When its not connected there will just be static data there. You usually want to put target AFR and wideband AFR on the same monitor so you can compare. Probably with map and rpm (and anything else you need to monitor at the same time) on the other one.



ah ok, to make sure I'm getting this right... The PCM uses the injector settings and kinjflow against the relevant A/F and VE tables to determine the theoretical fuel demand of the engine, and runs the injectors accordingly. Then to tune the motor we set and forget the injector settings and kinjflow according to the engine build, set our desired AFR in the A/F tables, and then by comparing the target A/F table to the actual wideband AFR, we adjust the VE table to match.

Should i also maintain the A/F tables? Say ive logged and set my VE table as above and im happy, i then find the motor makes more power on the dyno with more fuel than the A/F table requests. Should i lower the settings in the A/F table and then data log again before adjusting the V/E?



delcowizzid wrote:It will use the cold engine a/f table upto the max temp for cold a/f setting in the scalers list probably around 28 or 40 degrees or there abouts if I remember rightly have a look. Initial run offset is added onto commanded a/f table and is decayed out by number of crank reference pulses over time


awesome thanks! ive found and checked these and they are suitable. I was just concerned when i found the temp rows go all the way to 104, but it doesn't use these rows unless demanded for in the scalers. Cheers

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Re: $12 to $12p conversion

Postby antus » Fri Jan 17, 2020 3:24 pm

ah ok, to make sure I'm getting this right... The PCM uses the injector settings and kinjflow against the relevant A/F and VE tables to determine the theoretical fuel demand of the engine, and runs the injectors accordingly. Then to tune the motor we set and forget the injector settings and kinjflow according to the engine build, set our desired AFR in the A/F tables, and then by comparing the target A/F table to the actual wideband AFR, we adjust the VE table to match.


Exactly! You might tweak the injector flow a little later on if in practice you run out of headroom in the VE table. You might bump the rate a little, and subtract a flat 10 or 20% off the VE tables if your running out of room.

Should i also maintain the A/F tables? Say ive logged and set my VE table as above and im happy, i then find the motor makes more power on the dyno with more fuel than the A/F table requests. Should i lower the settings in the A/F table and then data log again before adjusting the V/E?


Most of the time you would leave the AFR tables at stock. If you find you make more power at higher AFR you would modify the power enrichment to bring the numbers up when in PE mode. For a car that you want to always be making power you might change the AFR, but not necessarily, even in, say a track car, the driving style should keep the mixtures rich when you need it.

The notable exception would be different fuels. There are different ways to approch different fuels, but the way Holden202T did it and documented for methanol, changing the AFR tables to suit Methanol AFRs, seemed to me quite clean and sensible.
You might also change the idle AFRs table for engines or injectors that have trouble idling for mechanical reasons.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: $12 to $12p conversion

Postby Matadore » Fri Jan 17, 2020 5:50 pm

yeah ill need to change the injector flow and compensate the VE as there is a bunch of 98 and a 99 on the current VE. Is there an Exact relationship between injector flow and VE table where I wont effect the current actual AFR? the injector flow is currently on 0.0798 with 36lb/hr Siemens deka injectors


whats power enrichment? is that same a acceleration enrichment?

I was thinking ill change the AE table to 0 while tuning the VE and then back to the factory 0.36 before testing out the AE. good idea?

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