boostedcivicsir

i am posting here because (i think) i have faith in the wealth of knowledge in this forum. he hee flame suit ready:

97 lude, p0108 has an afc installed, been on there for a while no problems.

went through the flow chart:
clear procedure
afc reads 71kpa, hand held vac read 21 in/hg the same. data list at ecu read 7 in/hg

ok next
jump pin 2 and 3 at map,
check for vac with data list,
i am gathering it should be 0in/hg un jumped, and 30in/hg jumped

well, unplugging the map, goes to atmospheric, jumped no change, but plug the map sensor back in CAR NOT RUNNING, is 30in/hg. WTF. car off not running should be atmospheric.

next
ck sig from pin 1 and 2
there is 5 volts there

next
jump d3 and d12 at ecu
no change, always reads atmospheric
check d3 to map, no continuity, is this because of going through the afc?

one thing i know is the factory map reading at the ecu is backwards from what it needs to be. when i put a vac pump on the map, 30 in/hg with nothing, put vacuum to the map sensor, it goes into pressure.

this is weird. 3 map sensors all the same, BUT THE AFC reads correctly.

WTF! it is to the replace with known good ecu point.

any help is appreciated.

boostedcivicsir

bump please

tony1

Is the afc set to 0 on all fuel settings? IN at 6 and out at 6?

boostedcivicsir

6 in 6 out
no fuel correction on low
pulling fuel out on high
no changes below 89% throttle.

HiProfile

Not that I know much about the afc, but 71kpa is ~8.27 Hg", and a car should be idling around your 21 Hg" measurement. I'd say check your stock MAP sensor maybe, check voltage between the middle and right pins. Assuming its like civic sensors, it will read 0.8 volts. If I've done all the math right, thats the voltage for 21 Hg" on a 1.75bar 5volt sensor.

And for the record, I hate nothing more than converting from bar to kPa to Hg"...

BTW I don't think its a good idea to short a MAP sensor. You read their output with a volt meter, not with an AFC while shorting the sensor leads. But if I follow your train of thought, Honda sensors are 1.75bar, meaning shorted low (+0v) would be 30 Hg", shorted high (+5v) would be 11.2ish PSI (Hg" is vacuum only, but in this case could be -22.8 Hg").

boostedcivicsir

online conversion 71kpa = 20.996 in/hg
http://www.onlineconversion.com/pressure.htm

fwiw, 3 dif maps, all same result.
chiseling out the afc to see if that makes a difference.

boostedcivicsir

even with the afc out of the picture, still the same.

at idle, 8in/hg on the scan tool, 23in/hg at the manifold

even if there were limmited vac getting to the sensor i.e. blockage, with the car not running, it shouldnt be at 30in/hg.

this is quite possibly the weirdest problem i have ever seen.
now we are back to ecu replacement.