Part throttle tuning question
10-23-2003, 02:06 PM
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Part throttle tuning question I got my Innovative Motorsports LM-1 wideband installed the other night and took the car out for a spin last night. You could say that I am running rich, both at part throttle and WOT, LOL. So my question is this: how do I tune for part throttle? I already have my LTRIMS slightly negative, and they lock at 0 when I go WOT. But at part throttle I am seeing numbers from 17 all the way to 21! How do I get it back down to 14.7 with LS1 edit? Thanks in advance!
10-23-2003, 04:59 PM
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Re: Part throttle tuning question Under what driving (load) conditions are you seeing the high AFR numbers? Something is not in sync. Either your O2s are putting out false info or your wideband is not reporting correctly. Your LTRIMS are slightly negative which tells us that the PCM is pulling fuel to achieve the target 14.7:1 AFR (closed loop), yet the wideband is reporting a lean condition. The PCM would have to add fuel to achieve 14.7 AFR and that would result in positive LTRIMS. Remember, the target AFR is always going to be 14.7:1 when the engine is up to operating temps and in "Closed Loop". During WOT, the PCM leaves Closed Loop and fuels via MVE and PE.
Richard
Richard
10-23-2003, 05:15 PM
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Re: Part throttle tuning question I ran in to the same problem and it is related to heat. When I installed the bung, I placed it approx 4" north of the drivers side cat... which was about half-way between the manifold collector and the cat.
At start-up everything looked good, just a little rich, but soon after once the sensor began to heat up, the afr would slowly climb to as high as 38:1 which is impossible.
I then contacted innovative and they recomended that I fab a heat sink out of copper and place it in between the sensor and the bung to dissapate heat. This worked at first but after the car was ran for a while, it would heat up again and show some very high o2 readings. I then tested it just to make sure that it was in fact a heat problem. With the car running, showing 38:1 I then took a leaf blower and hit the sensor/heatsink with it. As soon as I did that, the afr began to drop and centered right on 14:7 +/- .3
Basically, I'm out of luck right now until I can get long tubes and place the sensor bung further away from the motor.
At start-up everything looked good, just a little rich, but soon after once the sensor began to heat up, the afr would slowly climb to as high as 38:1 which is impossible.
I then contacted innovative and they recomended that I fab a heat sink out of copper and place it in between the sensor and the bung to dissapate heat. This worked at first but after the car was ran for a while, it would heat up again and show some very high o2 readings. I then tested it just to make sure that it was in fact a heat problem. With the car running, showing 38:1 I then took a leaf blower and hit the sensor/heatsink with it. As soon as I did that, the afr began to drop and centered right on 14:7 +/- .3
Basically, I'm out of luck right now until I can get long tubes and place the sensor bung further away from the motor.