no rpm signal on maftpro

dbsupra90

toonar
Apr 1, 2005
2,374
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indiucky
got everything running, but cannot get an rpm reading on the maftpro controller. ive rechecked the wiring and setup but still nothing. reflashed the unit w/ 4.65 and setup again to no avail.

i do have the rpm signal in IGF instead of IGT but its the same signal so that shouldnt matter. or does it? i had asked another couple users and they said it shouldnt. the afc worked fine, but cannot get the mafpro to read. everything else (map, a/f, tps, etc) all work.

any ideas?

no codes either btw.

thanks
 

dbsupra90

toonar
Apr 1, 2005
2,374
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indiucky
oh i thought i might add i removed the R7 resistor from the mafpro for the timing monitor. that shouldnt make a difference since its a pull up resistor for the afm but thought id mention.

mattjk- i'll ohm it out and/or try another wire.
 

tookwik4u89

Red T-shirt
Apr 6, 2005
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Rockford, IL
Dave, since you got the wires all wrapped up, unplug the connector at ecu, and m-pro, and make sure you have continuity through there. Also, you have the yellow wire to G2, and F-in set to 20 right? Not sure that would make any diff either, but I thought I would mention it since that stuff is not in manual.
 

dbsupra90

toonar
Apr 1, 2005
2,374
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indiucky
well we ran my friend's rpm signal from his ecu to my mafpro and still no rpm. so it has to be something w/ a setup or the mafpro itself. any ideas?

also, i think im gonna go ahead and hook the yellow wire to G2 and set Fin to 20 again. i had it set at 20 but didnt have the G2 hooked up. i guess its worth a shot.
 

dbsupra90

toonar
Apr 1, 2005
2,374
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0
indiucky
GrimJack said:
Pull the MAFT plug with the RPM wire in it and check for continuity from the MAFT plug to the ECU plug...

yep checked that just incase there was a break in the wire. that tested fine.

mattjk said:
they are the same.

negatory ghost rider. in theory they should be the same signal and was told by others the same thing. and like i said the afc works on either. the mpro however, not so much. andy had his afc wired off the IGF as well, and didnt work earlier. but thought id try to splice into the IGT just for fun and sure enough i have rpm signal. so.... problem solved! thanks for everyone's suggestions.
 

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
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Redacted per Title 18 USC Section 798
They are not the same. They do not occur at the same time and have very different signatures. IGf is very short, only as long as it takes the coil pack to discharge. It's only about 1 ms long. IGt is over 10 times that duration. It's no wonder you had trouble picking it up.
 

dbsupra90

toonar
Apr 1, 2005
2,374
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indiucky
well i guess so. afc will read either just fine tho. and several others told me on the mpro either would work as well. i dunno, im just happy its fixed.
 

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
There's no guessing about the theory for those who understand it. You were just another victim of those who don't know what they don't know. If I'd been around to see this post earlier I could've told you the problem right off. IGf is generated on the falling edge of IGt after the ignitor determines dwell while IGf is generated by flyback from the coil. As such it's going to be very short. The AFC could simply be better designed or wired but even though it may capture such a short duration it's still not the right signal to use. The tach in the dashboard is derived from IGt for a reason.