Martin in Bellevue
07-08-2005, 10:58 AM
Disclosure is provided here, for those interested in the maf conversion. Pro Flow is now out of business.
Last weekend, after making a slight adjustment to the 2nd pot, for off throttle response, the motor developed a bad tip-in response. The adjustment was minute, with the pots in "fine setting" mode. Normally, pot adjustments can be fairly broad while maintaining good running characteristics. A few days ago, the dme decided that the signal afm signal was crap & lit the check engine light. It now ran poorly.
I checked the maf wiring for continuity & shorts. I replaced the maf with a rebuilt maf for a 98 mustang cobra. It was better, but still not right. I swapped in a good, never-opened dme for no change. After Jeffro's track day, maybe we'll compare & isolate the exact problem. Oh yeah, the signal box still talks to the peecee & can accept new curve settings. Its output on the car is limited to about 0.2v, the problem.
Borrowing Jeffro's afm was a revelation. The throttle lags a little against the maf setup, but otherwise, the stock afm can be good. Driving around town for a day now, with the Jim C chip, the 284 regrind cam, the headers, 15lb flywheel & some other questionable mods, left the impression of a very tractable, torquey motor. Even with the 21lb injectors, the mile-o-meter shows a little love.
I may look at the latest split second maf signal conversion box. It allows secondary inputs for mapping purposes & looks to be well supported by the company. Daniel Ma had this on his '88 m5 & commented on its ease of tune. Walt's early pro m maf conversion died a couple months ago & he recently went with the latest split second maf setup. I may get another afm with wire connector. I gave my afm to a local e28 guy in need.
Up to that time on a ferry back to hippieland, the maf ran great. I mean to say, it pulled hard & made a glorious cavitating sound past mid-throttle.
http://www.bimmer.info/bmw/Martin5er/m30maf.jpg
Last weekend, after making a slight adjustment to the 2nd pot, for off throttle response, the motor developed a bad tip-in response. The adjustment was minute, with the pots in "fine setting" mode. Normally, pot adjustments can be fairly broad while maintaining good running characteristics. A few days ago, the dme decided that the signal afm signal was crap & lit the check engine light. It now ran poorly.
I checked the maf wiring for continuity & shorts. I replaced the maf with a rebuilt maf for a 98 mustang cobra. It was better, but still not right. I swapped in a good, never-opened dme for no change. After Jeffro's track day, maybe we'll compare & isolate the exact problem. Oh yeah, the signal box still talks to the peecee & can accept new curve settings. Its output on the car is limited to about 0.2v, the problem.
Borrowing Jeffro's afm was a revelation. The throttle lags a little against the maf setup, but otherwise, the stock afm can be good. Driving around town for a day now, with the Jim C chip, the 284 regrind cam, the headers, 15lb flywheel & some other questionable mods, left the impression of a very tractable, torquey motor. Even with the 21lb injectors, the mile-o-meter shows a little love.
I may look at the latest split second maf signal conversion box. It allows secondary inputs for mapping purposes & looks to be well supported by the company. Daniel Ma had this on his '88 m5 & commented on its ease of tune. Walt's early pro m maf conversion died a couple months ago & he recently went with the latest split second maf setup. I may get another afm with wire connector. I gave my afm to a local e28 guy in need.
Up to that time on a ferry back to hippieland, the maf ran great. I mean to say, it pulled hard & made a glorious cavitating sound past mid-throttle.
http://www.bimmer.info/bmw/Martin5er/m30maf.jpg