Tips for MAFT Tuning
Thread Starter
Teching In
Joined: Apr 2002
Posts: 30
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From: Milford, MA
Tips for MAFT Tuning I have recntly purchased TR ported MAF ends, Autotap and an MAFT. I plan on installing the ends and doing the tuning soon and am looking for some advice. I have been reading up on the topic and it seems I'll need to look at LTRIMS B1 and LTRIMS B2 at cruising speeds an OB1S1 and OB2S1 at WOT. I'll need the Throttle position sensor angle, fuel trim cell, A/F ratio, Knock Retard %, engine speed, vehicle speed and timing advance. Now is there anything else I'll need to look at? Also I heard that are O2 sensors are not that accurate and I will have a tough time getting a good tune with ATAP and MAFT is this true? Will ATAP give me the actual A/F ratio or the expected A/F ratio by the PCM? Any advice on properly tuning my car will be appreciated.
Note: My car runs a bit lean as it sits. I have gotten a little KR in my baseline runs. No more than 2.3% but still some nonetheless.
Note: My car runs a bit lean as it sits. I have gotten a little KR in my baseline runs. No more than 2.3% but still some nonetheless.
Re: Tips for MAFT Tuning You don't need to look at the A/F ratio or vehicle speed, either. The fewer parameters you monitor with Autotap, the faster the refresh rate. A/F ratio is the PCM's desired value- which is always 14.7:1 except under PE mode. Stock O2 sensors are not very accurate, dyno tuning with a wideband is ideal. If this is not an option, shoot for WOT O2s somewhere between 0.88-0.91. KR is measured in degrees, not percentage. You can try going richer on the MAFT to eliminate KR, but if you're getting false knock it won't go away. Generally speaking, you want to go as lean as possible at WOT without KR. At part throttle, shoot for LTFTs as close to 0 as possible staying below 0. Dial in your base first, then move on to adjusting WOT setting. Base adjustments on the MAFT will affect WOT. Only look at LTFTs in fuel cells < 17 - cells 17-20 are for idle, cell 21 is deceleration, and cell 22 is WOT.
