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vague tuning post



Well the 3800 computer doesnt really use the MAP sensor to make major choices at all.

All it does is take in MAF sensor data and really doesnt care what the MAP says because it doesnt use a real VE table.

Fueling comes from the MAF, timing is whatever and blah blah.
 


Not attempting to argue with anyone, being completely genuine... why would GM have spent the money installing a MAP sensor on the vehicle if it is unnecessary? Surely it has some meaningful purpose?
 
Why would the 3800 PCM not use a "real" ve table as in wtf defines it in this community for not being real or valid?

Not asking for a LS motor reference either. Nobody seems to have a answer .
 
Because everything is based off the MAF sensor???

Is the MAF sensor is plugged in and working correctly it will pretty much only use the MAF readings to determine everything.

There is no table like in a LS based computer for things like steady state hi/low rpm or map deltas or anything that says when it will only read from the MAF after a certain rpm.

It's pretty much maf all the time, the stock ****ty ve table that 3800 has might be used to provide transient condition correction to the main airmass calculations.


And if you go above 140 kpa and per the VE table, there is NOTHING after that. So after 6-7 psi of boost that table is worthless and thus the MAF does everything.
 
Nobody seems to have a answer .
Click to expand...

Except for me, several times.

There is a VE table for fail safe. Nothing else. If you zero it out, the car runs identical. If you zero it out and unplug the maf on a car that has the "failsafe mode" set to alpha N it runs the same as if you have the VE table zero'd out. If you set the "failsafe mode" to VE then it wont run.

Very common programming methods include configurations that enable different routines at different times under different conditions.
 


darkhorizon said:
Except for me, several times.

There is a VE table for fail safe. Nothing else. If you zero it out, the car runs identical. If you zero it out and unplug the maf on a car that has the "failsafe mode" set to alpha N it runs the same as if you have the VE table zero'd out. If you set the "failsafe mode" to VE then it wont run.

Very common programming methods include configurations that enable different routines at different times under different conditions.
Click to expand...
thank you, now see if these were the types answers instead of lol and other legendary douchebaggery nobody would doubt you.
 
I did a pretty goof job of explaining injectors.. offset vs static flow. No injector is truly that linear... ford ecus actually run a low pw slope and a high pw slope. Gm ecus do not discriminate and 1 slope provides everything with many offset modifiers that most 3800 tuning software does not have. Some like tinytuner and cats have some injector offset stuff but i have never been able to verify its correct. Ls cars i tune respond very predively to offset changes but no 3800 has ever done what i expect with offset adjustments. The amount of adjustments needed in offsets with the common 33 to 120lb inectors we use are very small and closed loop or minor maf tuning will correct it.
 
There are no real decent cold start tables for 3800s. Offsets are typically the best place to tune starting but i haven't had good luck with it. What is it doing or not doing now? Very very few 3800s out there start poorly on stock startup stuff.
 


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