I think i mean open loop (before the car warms up.) Any ways i am getting a MAF code being thrown but the runs alot stronger befor it goes into closed loop. So does the car use the MAF reading before the car is warmed up?

 

The PCM uses the MAF sensor ALL the time. That's the only way it knows how much air is entering the engine. There is the provision to default to speed-density on loss of MAF signal, but that's the only time the MAF wouldn't be used. If you have a code, its possible that you are running speed-density all the time.

If you have a code, what is it, and why not fix it?

 

The code that i am getting 3 of them that is the first is p0100 MAF frequency Insffient variance

the second is p010c

third is p0002

I have NOT got a SES light from this, I read the code using auto tap

I tryed replacing the Pink power wire as suggested before and i have also swapped MAF's with no difrence.

I need to find out more about theys codes and stuff to check

BTW the MAF is NOT descreened or ported

 

TTT for the afternoon crew

 

You might want to rechack those codes.... there are no OBD-II codes in the format of Po10c..... no alphas are used in the last four positions, only numerics.

Also might want to check P0002.... the lists I have seen do not show any codes lower than P0100.

Shoebox's code list, which is very reliable, shows:

P0100 = Mass Air Flow (MAF) insufficient signal activity

Common cause is a loss of the +12V power supply to the sensor. Pull the harness connector off, and with the key on, engine not running check for +12V at the pink wire in the harness plug. There is a fuse that supplies that power.

 

WHAT??? Wow this is the first time I think that you have ever been wrong fred The MAF sensor isn't used in open loop, open loop = speed density and uses the Open Loop AFR tables for fuel calculations in open loop!

 

Nah, I think fred is right... the MAF sensor output is used for the open loop AFR table.

 

Yep, my MAF bit the dust and the engine ran the same in open loop as it did in closed loop, so rich there are no mosquitos left around here.

 

You were also under the impression that the PCM switched to speed-density at WOT if I recall

 

Well in a way the computer does sorta switch to speed density if you wanna get technical about it. Which I know you like to do. When in WOT the computer goes into PE mode which STILL uses the VE Tables that are ALSO USED IN Speed Density mode!

BUT that still has nothing to do with you being wrong about the MAF being used in Open Loop

 

"Speed/density" = no MAF input used.

"Closed loop" = O2 sensor input used.

"Open loop" = no O2 sensor input used.

Open loop still uses the MAF input. Try running your car without the MAF in open loop and see what happens.

Rich Krause

 

It gets parked for two weeks while you wait on a new one.

 

Of course, it will run in speed/density mode in open or closed loop without an MAF. But if it's running in its' "normal" mode (not really sure what to call it other than "normal") it won't run without the MAF, AFAIK.

Rich

 

Not sure you've convinced me, or anyone else who has posted that you are correct.

Is this some little game you like to play, or are you singling me out for your personal attacks?

Just curious.

 

That's not very nice. Your one of the LAST PEOPLE that I would ever think about attacking personally as I know that your not a troll and do know your $hit but that's why I was so surprised to see that I thought you were wrong...

If you take a look at THIS DIAGRAM you will see that in this book I have it is showing that OPEN LOOP doesnt use all the sensors on the left and it only uses the sensors on the right. BUT after looking at it even harder it HAS to be WRONG cause its showing that it still uses the o2 sensors in Open Loop which we all know is WRONG. Plus I was reading up on some other material that I have and it completly contradicts what that diagram shows.

So that's where my confusion came from. I just remember seeing that diagram and it's always been stuck in my head that open loop does not use the MAF when really it DOES, BUT you can still be in open loop and have NO MAF and that would be considered speed density open loop..


Hope that clears it up a bit