i doubt too many people are having this problem.

i dumped my mass air awhile ago. at the time i was concerned it wouldn't do the timing right since the timing table is based on the maf reading but it still did the timing just fine. recently i wanted to get rid of the check engine light so i went in and shut off the codes that taking out the maf set. that was a bad idea.

with the code set it went into some kind of back up timing and must have been estimating the maf and still used the timing tables. with the codes killed it assumed the maf reading was correct and literaly used that reading wich was something like 0lb/min. on the timing table that puts it into some very high timing numbers. like 45deg high. truck runs prety good at 45deg but shows knock .

i need to go back in and see if i can just kill the light but keep the test and code. i dont want to kill the light entirely but i can do that too if i need to by puting a piece of tape over it.

 

you can kill the code(s), just set them to no mil light. If you set them to no error reported, yes the computer will think your telling it to keep using the data from the non existant maf

 

I'm surprised that the truck would even run with the code disabled and no MAF present.

Seeing as how you're an EFI Live user, Parish, you'll want to look at table C6002 - Engine DTC MIL Enablers. Set P0101, P0102 and P0103 to No MIL.

For timing lookup, the PCM uses GM.DYNCYLAIR to reference load not the MAF directly. When in MAF mode, DYNCYLAIR is built from MAF and VE input (depending on the driving condition). When in SD mode, DYNCYLAIR is built from VE only.

 

i do not use the stock computer for fueling so that is why it still runs.

clearly i am no computer/tuning expert. i just learn enough to get by. it sure is nice not having that light in my face so i will go set it to no mil. thanks.

 

Ah, I was wondering if you were using the Megasquirt for that or for other purposes. Are you running two map sensors? One to the PCM and one to the Megasquirt computer? Or are they both tied into the same system.

 

2 maps. the megasquirt has one built in.

i use the megasquirt to run my nitrous too. works well.

 

 

this thing is over a year old.

 

i just wanted to read it later. didn't have time at work.