Closed Loop A/F for FI
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Joined: Mar 2005
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From: FL
Closed Loop A/F for FI
Just wondering if any of you FI guys that are not running a maf, have any issues with your a/f under closed loop. Seems to me that the ecu is constantly adjusting and fighting my piggy-back unit. I know these OBD2 cars are a pain to tune and you need a lot of dyno time to properly do it. Obviously, if you have a full standalone, this doesn't apply.
Lexus Champion
Joined: Jun 2003
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From: Texas
Just wondering if any of you FI guys that are not running a maf, have any issues with your a/f under closed loop. Seems to me that the ecu is constantly adjusting and fighting my piggy-back unit. I know these OBD2 cars are a pain to tune and you need a lot of dyno time to properly do it. Obviously, if you have a full standalone, this doesn't apply.
JP Importz
Lexus Champion
Joined: Aug 2004
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From: California
What piggyback are you running? You have to keep this in mind. The stock ECU will try to keep the A/F in 14.7 range. Your close loop A/F will be determine on a couple of things: o2 sensor, coolant temp etc. Stock ECU will look at the 02 very closely and make the adjust from there.
JP Importz
JP Importz
He's using a Map-ECU with his 2jz-gte VVTI ecu.
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From: FL
correct It is a great unit. You just need some fine tuning. They have a new map-ecu2 coming out in late January. It has a O2 simulator signal map to trick the ecu. Specifically for OBD2 cars and this situation. I just don't want to buy another unit. I know it will work, you just have to find a median a/f. They are using them on Supra's and IS 300's all day. I think we got it real close yesterday. Also, when you change the injector size to 850cc like I did, your voltage needs to change too. We found that the maf was sending out a voltage of like 270 and that needs to almost double for startup to be optimum.
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From: The Rotten Apple
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