NewStangDude

Got the duals put on today. Been running the single GT takeoff and had been wanting to go to duals for sometime, but my schedule has been preventing me from getting it done. Took the day off to do it today. Used the Ford hanger brackets and midpipe. Midas did the honors on the H-pipe. I thouhgt it was neat the way they did it. The guy fit everything on the car, tacked it then took it off and completed the welds. It was single piece that slid back on, sort of like an X-pipe. Used the Ford slip connectors too for connecting the midpipes to the H-pipe. I had them cut the stainless tips of the mufflers about 4.5 inches from the muffler bodies and slid the Ford chrome tips on. It looks good. Sounds better. The single GT takeoff was far better than the stock V-6 muffler, and the dual GT's are better still. A little deeper tone and marginally louder. Just what I was expecting based on the comments and sound clips of others.
No problems all day, but coming home from dinner tonight the CEL came on. The X-Cal ll read P0171 and P0174. I cleared the codes before reading them, but I think HurricaneStang said the first one was too lean. Not sure about the second. Shouldn't the tune compensate for this? Of course I didn't have duals when I bought the tuner so maybe the tunes need to be tweaked. But you wouldn't think duals would make that big of a difference with the tune. I can change the intake and/or filter back to stock if I have too, but would rather not. Anyone have any suggestions?

Jerseyfury2

odd....i mean, you will be losing a fair amount of backpressure i'm pretty sure. if that's lean...there might be something with the o2 sensors would be my best guess.

HurricaneStang

Ya my lights on too. I checked and the PO171 is the running too lean dtc. I cant even figure out how to clear them but i have an appointment at ford tuesday because there is definately somethin wrong with mine....knocks from under the car, brake pulses alot and when i accelerate i can just tell its not right....i wish i wouldntve taken it to boubin

fazm

0171 is system too lean bank one, and 0174 is system too lean bank 2.

usualy cause for these are vacuum leaks, or a bad maf sensor (or a bad tune)

HurricaneStang

Well i would guess my case wasnt the tune since it was running good for 2 months before the exhaust then the day after i have the exhaust done its messing up :/

scrming

Kind of odd... i'm running a custom off-road pipe... so i'm thinking I've about the least amount of back pressure here.. and i've never thrown an CEL.. hmmmm...

NewStangDude

You're right scrming, it is odd. What's more odd is I cleared the codes Friday night and drove for about an hour or so Saturday around town and no problems. I was about 5 minutes from home and the light came back on. This was just after a full throttle acceleration. Got home cleared the codes again and so far no CEL. Just as additional info, I reset the ECM after the duals install by disconnecting the battery and reloaded the tune with adjustments to the idle RPM in drive. No other changes. I've been running the 91 tune almost since I've had the X-Cal ll, 4 plus months. I've sent an e-mail to my tuner to see if he has any suggestions. We'll see.

Thanks to all for your responses.

NewStangDude

As a follow-up to my own problem, I recall the X-Cal having an adjustment for WOT fuel percentage or something similiar to that. I'm going to plug it in and see exactly what it does say and make a slight adjustment since the CEL can be reset and stay off for some time before coming back on for the same problem. It seems to come on only after heavy acceleration. I'll see what that does and keep you posted.

HurricaneStang

So how do you reset the codes?

NewStangDude

After the codes were detected and displayed on the screen I scrolled down to the next selection, which was the clear option. I hit select and the codes were cleared. After the first time the codes were read I just kind of scrolled around to see what my options were and found the clear selection. Good luck!