Car runs perfectly fine... except between 4800-5k rpm where I have 0 power. Help!!
06-06-2016, 02:18 PM
#17
Three Wheelin'
At 75% throttle, you should be engaging the WOT microswitch. When the switch is engaged, the o2 feedback goes to open loop (ecu is not trying to maintain 14.7:1 afr anymore). In open loop mode, the ecu only relies on rpm and intake temperature to calculate the fuel and timing requirements.
Similarly, the AFM flapper will max out at higher rpm and moderate load. When the flapper is completely open from the in-rush of air, the ecu goes into the same open loop mode as when the wot switch is triggered.
In all other driving conditions, except quick throttle position changes, the ecu tries to maintain 14.7:1 afr using feedback from the o2 sensor. In reality, the afr will bounce between about 14.2 and 15.2.
Easy checks: 1. The intake air temp sensor reading (there is an ohm vs temp chart in the manual), 2. Make sure the afm flapper moves smoothly and easily, 3. Pop the cover off the afm and move the contact scraper to a fresh and un-worn electrical track.
Good luck!
Similarly, the AFM flapper will max out at higher rpm and moderate load. When the flapper is completely open from the in-rush of air, the ecu goes into the same open loop mode as when the wot switch is triggered.
In all other driving conditions, except quick throttle position changes, the ecu tries to maintain 14.7:1 afr using feedback from the o2 sensor. In reality, the afr will bounce between about 14.2 and 15.2.
Easy checks: 1. The intake air temp sensor reading (there is an ohm vs temp chart in the manual), 2. Make sure the afm flapper moves smoothly and easily, 3. Pop the cover off the afm and move the contact scraper to a fresh and un-worn electrical track.
Good luck!
06-07-2016, 04:02 PM
#18
Racer
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Join Date: Jan 2013
Location: Wilmington, NC
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Hey guys thank you so much for the help with the afm. It was the issue! I took the afm off, and I took the black cap off (really tough to get off, managed to crack it a bit on the edges ): )
I saw that the tracks left by the arms on the meter were really deep, especially towards the end. I followed the guide on the video you guys linked, and a video I found on youtube of a BMW afm (they are incredibly similar)
I took off the mechanism with the arms and bent the copper to a new track. I put it back on the afm and put everything back together. I took the car out and it ran smoother and better than ever.
0 issues, no hesitation at all.
Thanks everyone!!
bonus: pictures of the afm sweeper arms and track
I saw that the tracks left by the arms on the meter were really deep, especially towards the end. I followed the guide on the video you guys linked, and a video I found on youtube of a BMW afm (they are incredibly similar)
I took off the mechanism with the arms and bent the copper to a new track. I put it back on the afm and put everything back together. I took the car out and it ran smoother and better than ever.
0 issues, no hesitation at all.
Thanks everyone!!
bonus: pictures of the afm sweeper arms and track