How can MAF dropout be programmed around?

[2QUIK6]

Anyone know if MAF Dropout can be programmed around in the stock type of chips and how can I do it?

Never was a problem before, have Trans+ on the GN, and used a Thrasher in my TTA or burned my own before I could max out the MAF, but now am experiencing it with my TTA and the Thrasher chip I have does not have enough fueling in it for the boost I'm trying to run.

 

[87GN_70GS]

I hope Carl doesn't mind me reposting his patch for locking the BLM to 128 at WOT:

To insert the patch, change $3D65 and $3D66 to $3B 1C so it will jump to a block of zeros that we can use as a patch area at $3B1C instead of to $3EAF. At $3B1C insert my patch: $91 36 22 02 97 81 7E 3E AF. The last byte, $AF, is at address $3B24. This translates to:

3B1C: 91 36 CMPA $36 Compare A (=$80 =50%TPS) to %TPS
22 02 BHI END Branch if <50% TPS
97 81 STAA $81 Store the new BLM
END: 7E 3E AF JMP $3EAF Go back to normal code

 

[2QUIK6]

Thanks! So by locking the BLM to 128 with that code prevents MAF dropout when the MAF hits 255?

 

[ijames]

No. Locking the blm has no effect on the maf overflow problem. That requires a separate code patch; I've never done one for myself because I think using the tranlator is the easier/better solution . Also, this was my first blm lock patch which uses 50% tps as the trigger. If you search the gnttype archives you can find my later patch that lets you set a maf threshold which I think works better. Either way, enjoy.

 

[2QUIK6]

I need to cure the MAF overflow problem with the stock code. This is only temporary on the TTA as I'm testing an experimental turbo then it will be returned to stock so the LT1 MAF is not an option for me.

 

[ijames]

Not trying to be sarcastic, but if it's only temporary anyway why not borrow the ls1 maf and trans+ from the GN? Don't hook up the timing control and it should be a quick swap. I've never seen anyone publish a maf lock patch, and I do know that it is somewhat nontrivial, so I will be (pleasantly) surprised if someone gives you one.

 

[bruce]

Originally posted by 2QUIK6
Anyone know if MAF Dropout can be programmed around in the stock type of chips and how can I do it?

Never was a problem before, have Trans+ on the GN, and used a Thrasher in my TTA or burned my own before I could max out the MAF, but now am experiencing it with my TTA and the Thrasher chip I have does not have enough fueling in it for the boost I'm trying to run.

It's a code, and hardware problem. The only real cure is a Translator, and Extender type chip, as far as I know. The MAF is only meant to be read between 30-150 Hz, and the stock MAFs can read well above that. It's been a while since I dialed it all up on the bench, but as I recall all it takes is ~155 Hz for the code to foul up.

The MAFless ME, does away with the MAF. You'd have to check with Steve Y, about if he does something to just eliminate the MAF input reading at WOT, with the regular ME.

Like Carl said, if you want to tackle it in just code, it probably wouldn't be easy.

One other option is rewiring the ecm, internally to get rid of the onboard ROM, and then developing Source Code, and rewritting that to be a full MAP system, figure 3-4 years on that.......

 

[2QUIK6]

I figured if it was a fairly easy change in the code I'd do that rather than unbolting the Translator from the GN and and mounting it in the TTA, seems like there is a power wire to splice in too, can't remember...it would be in there for several track runs.
I may just borrow an adj fp reg and slap on it and crank the pressure up to accommodate the needed fueling in order to use the Thrasher as the MAf dropout is eliminated in the Thrasher chip as well that I already have.