koolrayz

iTrader: (26)

I have stock headers and Y pipe. I was going to install another bung in front of the cat but cant see that there is any room. even if a got it in i dont think i could get the sensor screwed in. Can i take out the front sensor and use the existing hole while dyno testing? I dont care if it throws a code i can reset it. PLEASE HELP

Billiumss

iTrader: (11)

Hi Ray,

Take out the front O2.

I did that with Jay's car and it worked fine. Just wear gloves, it's hot up there!

CAT3

iTrader: (9)

NO, you cannot take out the front O2 to get an accurate wideband. Once you d/c a front O2, you put the PCm in a "limp" mode, where the PCM adds fuel to play it safe. I tried this already and found out afterward. Although the wideband showed a 12.5:1 on WOT, I was actually lean once having both O2's hooked back up. So, I am getting an O2bung welded in and a plug, so when I need it, I can WB.

Charlie.

Billiumss

iTrader: (11)

O2 bung is ideal, but you'll be fine Ray. The computer doesn't use the front O2 during WOT, that's what the tables are for, that's why we tweak them...

Like I said, it worked on Jay's car during our dyno day and he picked up 12hp on a stock car!

koolrayz

iTrader: (26)

Thanks Bill, I have an appointment on the dyno at 9am before work. Ill let ya know how it worked out. I really cant see enough room to put an additional bung in on my stock exhaust.

ChrisB

You can increase the closed loop enable temp to keep the car in open loop - then just keep the o2 plugged in but tuck it away and put the wideband in the harness.

NoGo

iTrader: (2)

You can pull the front O2 sensors and do as ChrisB said above. Your car will dyno just fine.

The only problem is that you have to make sure that your LTerms aren't positive. If your Lterms are positive, then as soon as you plug your O2 sensor back in and get on it, it will be much richer.

Just check your LTerms first before tuning like this. Make sure they are negative when you get on the gas and lock at zero.

CAT3

iTrader: (9)

Ok Billiumss, NoGo, ChrisB:

So, is this good or not, I hooked up a wideband to the front O2, and actually unplugged the O2 that was there. Ran the car, had 12.5 WOT. I was told that unpluggin the O2 there would throw the PCM into a limp mode, is this right or no? If I leave the O2 plugged into the harness and just remove it from the pipe is that good?

Billiumss

iTrader: (11)

You can unplug it or let it hang. The computer doesn't use the front O2's for WOT, that's what the table are for.

Trust me, I've done it a few times now.......

WS6 GreeN

Leave it plugged in but let it hang

CAT3

iTrader: (9)

Ok. Conflicts but which one....oh well, will be adding an O2 bung this weekend. I did log 12.5 a few times, but then also got down as low as 10.x I guess I will add extra port for it and post up any discrepancies. Thanks.

koolrayz

iTrader: (26)

Bill, Thanks for the great advice it worked like a champ . Car pulled 375 rwhp at 4750 rpm. Now remember this is on a mustang dyno not a dynojet. I pulled 17% more horsepower on the dynojet at the club meeting than i had pulled previously on this same mustang. That would equate to 438 rwhp using the same correction on a dynojet. That was with a 100 shot and only 25 degree's of timing