need help with prop fuel tables in hpt
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
need help with prop fuel tables in hpt i posted this on hpt forum but hope i can get response here as well...
here is the problem. o2 oscillation is slow going down the street at times and if i throw the clutch in rpms will oscillate. I have messed with proportional fuel and it doesnt seem to be getting any better.
lets see if i am thinking about this right. proportional fuel tells the injectors how much more or less to stay on to switch around 14.7:1 when in closed loop. the higher the value more fuel will be added or subtracted. too much will cause "railing" of the o2s and too little will cause them to barely switch. slow oscillation will cause large and weird fuel trim changes and make rpms vary a lot. it seems i have come to a point where the changed to the proportional fuel arent doing much, and they are getting pretty low now from 56-723 in a fairly strait line. it seems that in cell 14 and 16 all is well, below the oscillation is slow but not bad, cannot tell what is going on. clutch in going down the raod they are all over, and that is at about cell 4.
so am i at a point where proportional fuel wont help? i was looking at the o2 error table thinking i needed to lower these values so the o2s wont hang rich or lean in the problem spots. this is about all i can think of. i have new denso o2s in my headers and heads and cam as well with ford 42# injectors. at idle they oscillate slow and oddly but rpms are fairly smooth. i can get a scan to show what i am talking about if needed, it just gets frustrating at times. let me know if i am on the right track and give me any advice you have to offer. thanks
here is the problem. o2 oscillation is slow going down the street at times and if i throw the clutch in rpms will oscillate. I have messed with proportional fuel and it doesnt seem to be getting any better.
lets see if i am thinking about this right. proportional fuel tells the injectors how much more or less to stay on to switch around 14.7:1 when in closed loop. the higher the value more fuel will be added or subtracted. too much will cause "railing" of the o2s and too little will cause them to barely switch. slow oscillation will cause large and weird fuel trim changes and make rpms vary a lot. it seems i have come to a point where the changed to the proportional fuel arent doing much, and they are getting pretty low now from 56-723 in a fairly strait line. it seems that in cell 14 and 16 all is well, below the oscillation is slow but not bad, cannot tell what is going on. clutch in going down the raod they are all over, and that is at about cell 4.
so am i at a point where proportional fuel wont help? i was looking at the o2 error table thinking i needed to lower these values so the o2s wont hang rich or lean in the problem spots. this is about all i can think of. i have new denso o2s in my headers and heads and cam as well with ford 42# injectors. at idle they oscillate slow and oddly but rpms are fairly smooth. i can get a scan to show what i am talking about if needed, it just gets frustrating at times. let me know if i am on the right track and give me any advice you have to offer. thanks
