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Title: Hitachi MLHFM Table - Offset? Post by: mercuric on August 25, 2013, 10:17:48 PM Hello all,
I'm a little confused about the mbox Hitachi MAF. I'm trying to understand the Linearization table (MLHFM) in an attempt to get a valid voltage/flow graph. Bosch MAFs have an offset, as the sensor reads negative flow below 1v. The Bosch stuff makes sense to me. The offset is defined by MLOFS, and is 2000 decimal, or 200 KG/H, which makes the Bosch MLHFM table sane, causing 1.0v to equal 0kg/h after the offset is applied. Good stuff. I thought I understood the Hitachi table, until I read: http://s4wiki.com/wiki/Mass_air_flow#Signal_conditioning The S4Wiki indicates the Hitachi MAFs also have an offset; with the sensor reading 0 kg/h at 0.5v. But as the Hitachi MLHFM table starts at zero and works it way up, and MLOFS is set to zero, it would seem the Hitachi MAF does not have an offset, and starts reading positive flow directly above 0v? I must be missing something? Any insight appreciated! Thanks for looking :) Title: Re: Hitachi MLHFM Table - Offset? Post by: nyet on August 25, 2013, 10:27:04 PM Yes. The hitachi maf cannot read reverse flow.
Title: Re: Hitachi MLHFM Table - Offset? Post by: ddillenger on August 25, 2013, 10:34:20 PM Contrary to popular opinion, Bosch>Hitachi.
At least in this mans opinion. Title: Re: Hitachi MLHFM Table - Offset? Post by: mercuric on August 25, 2013, 11:02:39 PM Awesome! Thanks! That's what everything including disassembly and maps indicated, but wanted to make sure I wasn't missing something important.
ddillenger, why do you prefer the Bosch MAF? I do not have enough knowledge of the differences to form an opinion, so I'm curious about your logic :) |