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Thread: E67 MAF Idle Frequency

  1. #1
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    E67 MAF Idle Frequency

    Hi, generally what would the MAF idle frequency be with a small 224/232 cam? Does 1500Hz sound about right?
    Trying to work out which Hz numbers to lower below 1000rpm as it's running rich ?

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    log maf hz with same as table layout as in editor and use fuel trims error % in the cells then u can see where its at idling and by how much to adjust it

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    Quote Originally Posted by 07GTS View Post
    log maf hz with same as table layout as in editor and use fuel trims error % in the cells then u can see where its at idling and by how much to adjust it
    Hi, my apologies it was a silly question. I didn't realize there was a PID channel for MAF Hz.
    Anyway idle is about 3500hz in park and 4000hz in gear. When i decrease the g/s values at these frequencies (make the maf leaner) it increases the MAP kpa and MAF Hz to 3800hz park and 4300hz in drive. The MAP goes from 65 to 80. Why is this?

    My objective here is to lean out the idle. In park there is a nice lumpy idle, but in gear it loses all the lump because 30% extra fuel goes in. I can tell by my instant fuel gauge and because the MAF g/s jumps up from 11 g/s to 15 g/s. Any help would be appreciated.
    My other issue which is a different subject, is my o2 sensors have no voltage even after replacing them, so I have no STFT to look at. Maybe the engine harness is faulty.

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    your "in gear" min airflow is prob little higher then the idle so u could lower that to get less load on the in gear but engine is also then against the converter so it will need more fuel as it loads up, u will need to get the 02's going as they can tell u alot and help with STFT corrections dialling in the maf/ve/vve for idle and cruise

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    The min airflow tables are the same between park idle and in gear. So it sounds like there's either too much fuel for that frequency or converter load up.
    Yes the o2 sensors are concerning. I just bought the car and it has no cats. The o2 sensor codes are on 'permanent' when i log the dtcs. P0430, P0030, P0050, P0155 and P0443. Do you think by installing cats the o2 sensors will start working again? If not it sounds like it needs a new engine harness.

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    02's should work with or without cats, ur fuelling may be just cos of the 02's not working as it may want to default a little richer as most OL tables can be so that is all that might be, and at the moment ur adjusting fuel without any feedback at all so it could be anywhere at a guess, best to fix the 02's first and go from there

  7. #7
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    you will not achieve a lean idle if your o2 are working, you will need to go OL and adjust your maf curve based on external o2 feedback
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    Quote Originally Posted by SultanHassanMasTuning View Post
    you will not achieve a lean idle if your o2 are working, you will need to go OL and adjust your maf curve based on external o2 feedback
    You mean if o2 sensors are not working?

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    if ur in CL ur 02's will always keep u at stoich so u need external feedback from wideband and go OL to dial it in properly, or if u at least had working 02's u could see if ur at stoich or not but they arnt accurate if u want an exact figure outside stoich