HELP for NATS!!! please???????????

[SonomaGTlover]

Just a quick question that I know nothing about....

I recently did the vortec upgrade and finished this past monday. Yes, Monday I was utting it close. I mocked up the exhaust Tuesday and realized that I completely forgot about the exhaust sensor that sits just before the cat. I assume it is an oxygen sensor, but the cat back has been removed completely. I have headers and true duals all the way back now.

QUESTION:
It seems to run great without it. just a slight hesitation on a quick throttle but that's probably in timing or something. Do I really need the sensor? What will happen if I leave it unplugged? Will I be OK for the weekend at NATS? Ahhh... maybe someone there will have a welder handy to weld the bung in for me? (yea right) I have everything, just didn't put it in.

Anyway, BIG thanks in advance to all that respond with opinions before I leave Friday morning. Bigger thanks to anyone that can weld it for me at NATS!!!

 

[MikeRenz]

Re: HELP for NATS!!! please???????????

i'd drive it...its just a sensor. :lol:

 

[gmcturbo]

Re: HELP for NATS!!! please???????????

do you still have a cat jon? id try to get the o2 sensor back in there youll probably get horrible gas mileage without it. itll probably eat the cat up some if its still there..

 

[dgoodhue]

Re: HELP for NATS!!! please???????????

I you have a cat, I would put it in. It will most likely get horrible gas mileage. The truck is running in open loop (not correcting the air fuel ratio at part throttle via the O2 sensor) so the ECM is just guessing at what fuel is needed (typically rich).

 

[SonomaGTlover]

Re: HELP for NATS!!! please???????????

Thanks guys!
I'm driving it like it is!
There is no cat so I don't anticipate any damages anywhere based on what you all told me. A little rich is no problem since it'll be in tow to/from and just local driving in KC.

Thanks again,
See ya there!

 

[SonomaGTlover]

Re: HELP for NATS!!! please???????????

Well, I started it up and let it run for awhile to top off the radiator and fill the tranny. You guys are right... running rich. I could smell it after just a minute or so.

It looks like I am off to the store to buy a welder and do it right. I found out that my linkage was a little off for the shifter as well... I have NO PARK! LOL.

At this point I am not sure I want to take it to NATS, we'll see how the welding goes. I didn't work this hard to get it done and leave it at home. Heck, I still have 24 hours before I have to leave.

 

[SonomaGTlover]

Re: HELP for NATS!!! please???????????

Well, I got the sensor in and back on the truck.

I didn't disconnect the battery and since it was running rich I am hoping that is why I am having issues now. I disconnected it now hoping to reset the ECM cause I was having an occasional backfire. I checked the timing and it's OK. I am just wondering if I need to advance it a bit with the vortecs? It's hit and miss at this point.

I plan to load it up and bring it to NATS anyway, maybe I'll think of something along the way.

 

[gmcturbo]

Re: HELP for NATS!!! please???????????

double check firing order jon.

 

[SonomaGTlover]

Re: HELP for NATS!!! please???????????

double check firing order jon.

Will do but I am sure I have it correct.
The backfire is just occasional as it sits there and idles. Like it's loading up or something. It seems to rev strong and idle smooth. It's mainly at start-up and long idle. Not sure what it does under a load yet. Is it remotely possible that with the higher flow heads, headers and slightly increased fuel pressure that it would do that? Will timing advance help any? That'll be my first attempt to clear it up if disconnecting the battery doesn't help.

Thanks for the tip though I'll definately double check it.