Ashley P Posted May 3, 2023 Share Posted May 3, 2023 Anybody ever modified a MAF on a Mitsubishi (or anything)? I've fixed an intermittent dying on stops by replacing the MAF. However, now it generates lean codes. Fuel trims are about 12% long, and often over 23% short. All input data looks accurate. Fuel pressure is perfect. Thus.... I believe the aftermarket MAF is not accurate. Multiple replacements are the same. OEM is unavailable. I'd love to "adjust" the MAF until fuel trims are close to 0. Any ideas? Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 3, 2023 Author Share Posted May 3, 2023 2003 Outlander, 2.4l fwiw Quote Link to comment Share on other sites More sharing options...
Disney Posted May 5, 2023 Share Posted May 5, 2023 That style of MAF cannot be "adjusted" to increase the airflow signal. If you're reading +LT and STFT then you would need the MAF to see more air. Impossible todo with that style of MAF. Checkthe fuel pressure to make sure it's in spec. Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 5, 2023 Author Share Posted May 5, 2023 Fuel pressure is "perfect". I'd need to lower the resistance of the signal, right? A variable resistor across the "hot wire"?? Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 5, 2023 Author Share Posted May 5, 2023 Edit: the resistor would be in parallel to the sensing wire, thus lowering the resistance of that circuit (as if airflow were greater). Quote Link to comment Share on other sites More sharing options...
Disney Posted May 16, 2023 Share Posted May 16, 2023 That could work. Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 16, 2023 Author Share Posted May 16, 2023 Well, that would be the hard way. I simply applied some tape across a section of the MAF screen to block about 15% of the area. The sensing wire is away from that area and will see a greater percentage of incoming air. Now the STFT ranges from -5% to 15%. Before it was about 15% to 24%. During open loop WOT, does the ECU use the MAF? Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 16, 2023 Author Share Posted May 16, 2023 So the cheap experiment yielded vastly improved STFT, but I still got a p0171 lean CEL just now. It took 4 test drives. Joy. Quote Link to comment Share on other sites More sharing options...
mstrpth Posted May 17, 2023 Share Posted May 17, 2023 could you still parallel a resistor or maybe 2? Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 17, 2023 Author Share Posted May 17, 2023 I guess. I'll have to do it in the harness outside the MAF...and have to find some resistors. Quote Link to comment Share on other sites More sharing options...
mstrpth Posted May 18, 2023 Share Posted May 18, 2023 https://www.amazon.com/BOJACK-Values-Resistor-Resistors-Assortment/dp/B08FD1XVL6/ref=sr_1_1_sspa?crid=1IFEJKGTI4N8&keywords=resistor+assortment&qid=1684410650&sprefix=resistor+%2Caps%2C83&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUE2NEpNRVBIVVNLRDUmZW5jcnlwdGVkSWQ9QTA1NjM0NjMyRjBHWVRZQjJISkNRJmVuY3J5cHRlZEFkSWQ9QTA1MzU1MjAzRTU3N1pZN0c3MlFEJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== Quote Link to comment Share on other sites More sharing options...
Ashley P Posted May 18, 2023 Author Share Posted May 18, 2023 Ha! 1000 chances to get it right! "So you're saying there's a chance?" - Some dumb guy Quote Link to comment Share on other sites More sharing options...
Ashley P Posted June 2, 2023 Author Share Posted June 2, 2023 I blocked a little more "frontal area" of the MAF. Now LTFT is about zero, STFT an various throttle is plus or minus about 6. Car is sent home, likely fixed. I hate Chinese parts. 1 Quote Link to comment Share on other sites More sharing options...
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