302travis

I have a 93 F150 5.0 with speed density. I have put LT headers, electric fan, and a cone filter on it using a 95 intake tube set up. And for the longest time i've just run with the o2 sensor unplugged on the default map. I have a nipple for it on one bank, and still have not found a straight answer from someone who REALLY KNOWS what the computer would do reading off just the one bank, or if I should spend a little more money and get an H pipe installed with a new nipple and place one as close to the front as possible? If i make an H pipe right after the headers and put the sensor there, would it read correctly? Beyond a shadow of a doubt. Or can it run decently on the nipple reading just one bank? I would really like to understand how this type of speed density system would react to either situation. I may get together with an electrical engineer buddy of mine to help me tune it a little by tricking it with any magic he can work with it. But i would like to know anything and everything on how these systems behave and react. Thank you anyone with info in advance!

sdmartin65

It. Will run off one bank. I'm sure you're aware, that right now you just running a rich baseline condition. Plug it in, worst case scenario you get a lean misfire. In that case you just unplug it again.

302travis

Yes I know it runs rich which is partly why I want to hook up the sensor correctly. Just to gain a little mileage back. And I have it hooked up currently and it stArted to have a miss below 1500rpm and under a load. Such as when it tries to lug up a hill in overdrive. So I'm guessing that would be a misfire from running lean?

sdmartin65

Yes that's s lean misfire

302travis

Well craP. Do you know if plAcing it in an h pipe or x pipe further downstream would allow it to read right?

sdmartin65

you say that you have a nipple for the o2 sensor on 1 bank. does the nipple let the o2 sensor fit properly in the exhaust stream? the reason I ask is if you think about it the factory bung sits at the cross of the y pipe . Maybe your setup gets too much exhaust flow across the O2. I believe the positioning of the o2 to be very delicate.

302travis

I'm Pretty sure its in there correctly but I will look into that. Although I think it just needs to read the average oxygen levels in the exhaust gas. Idk I'll see what I can find on that

Thomasje3

It misfires or misses when "lugging" up a hill in overdrive?
There is a difference. I have dealt with a similar condition in both SD and MAF systems and I ended up finding that the coil was shorting internal. Found the condition even worse when everything is hot under the hood. Check the resistance on both the primary and secondary side. I Think the secondary resistance should be 15K or greater homes if memory serves. I can't remember the primary resistance.
Also, install a wideband in your exhaust and hook up to a guage and keep an eye on your A/F ratio. In theory, having the O2 in just one header would at worst not correct for an issue with a cyl on the other bank. Be careful installing the O2 in an H/X pipe as it may be to far down stream and too cool for the O2 to opperate properly. There ate also flow issues with an H pipe that can hamper an O2 operating properly.

Good luck

302travis

Ok so been leaving the o2 unplugged and still random misses when i can get it to stay in 3rd or 4th at 1700rpm or less and give it a little throttle to try to get it to speed up without downshifting and she'll miss sometimes and not others. Then I realized, when i set the timing, I read the 10 degree marks as 5 degrees, so it's at 22 degrees base timing. But I don't get any pinging at ALL. SO, is it possible that I just need to back the timing off down to something more respectable for 87oct like 14-16 degrees? Could that be the issue? Or could one of my plugs have become fouled from the default fuel map running a little rich all day long? Thought also maybe an injector might be clogged(although i usually run some kinda fuel system cleaner in her about every 5000 miles), but I would think if it was an injector clogged it wouldn't be as isolated to a low speed load like this and would still miss at higher rpms as well? Am I wrong on that? I'm no expert, but I want to learn as much as I can! I appreciate everyone trying to help.

302travis

And yes i remembered to take the spout connector out, change timing, then plug it back in. In case anyone was gonna ask