MAF Hz and Load spikes at idle QUESTION ? ?
Sep 24, 2009, 06:51 AM
#16
I disabled the ignition warm up table
used the new method to disable the EGR
disabled both the EGR peripherys
zeroed out the base low engine temp trim table
zeroed the warmup advance activation table
........ and my cold start issue has vastly improved.
BUT
Now the car wants to idle hang. When it is cold it wants to idle at 1700+/- 200 RPM. Once it is fully warmed up the hang goes away. Then there is a slight issue with idle run down. If I push the clutch to roll to a stop it takes a while for the RPM to decrease to my 1000ish idle setting. Basically, it doesn't fall to idle quickly.
I may adjust the Idle error tables and see if I can get the idle to come down a bit faster.
used the new method to disable the EGR
disabled both the EGR peripherys
zeroed out the base low engine temp trim table
zeroed the warmup advance activation table
........ and my cold start issue has vastly improved.
BUT
Now the car wants to idle hang. When it is cold it wants to idle at 1700+/- 200 RPM. Once it is fully warmed up the hang goes away. Then there is a slight issue with idle run down. If I push the clutch to roll to a stop it takes a while for the RPM to decrease to my 1000ish idle setting. Basically, it doesn't fall to idle quickly.
I may adjust the Idle error tables and see if I can get the idle to come down a bit faster.
This is the minimum difference between the two bit values. The eval for 1 byte airflow only has a resolution in increments of 6.25. You can try 2 byte airflow for closer results at idle.
Sep 24, 2009, 07:02 AM
#17
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The only ISCV adjustments I made were for with the AC on to stop the car from stalling. Then, the only adjustments were done to the bottom 2 spaces....when the car is warm.
Sep 24, 2009, 09:52 AM
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Sep 24, 2009, 12:04 PM
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Oh and even after doing all of the stuff for cold start.....the MAF Hz still has spikes. It will be stable in thr 30s then spike to like 70, then stable again. I know the MAF Hz spikes are causing the load spikes since load is calcualted from airflow.
This is so frustrating.....the car idles well but bobbles every time the Hz spike occurs.
This is so frustrating.....the car idles well but bobbles every time the Hz spike occurs.
Sep 25, 2009, 03:44 PM
#24
Oh and even after doing all of the stuff for cold start.....the MAF Hz still has spikes. It will be stable in thr 30s then spike to like 70, then stable again. I know the MAF Hz spikes are causing the load spikes since load is calcualted from airflow.
This is so frustrating.....the car idles well but bobbles every time the Hz spike occurs.
This is so frustrating.....the car idles well but bobbles every time the Hz spike occurs.
Sep 27, 2009, 08:48 PM
#27
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Here is an odity I discovered today.....The load and Hz spikes don't happen if I have the A/C on. The car idles steady and smooth, albeit at 1250 rpm to cure stalling with big cams, intake pipes and port work.
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