TBI, Headers, Duals, No Cats, 1 wire O2????

[wayne]

Got the new engine fired up but having a few issues. I can't get rid of the service engine soon light and I think the O2 sensor is the problem. It's a stock crate TBI truck engine that ran great when pulled out of the Burb it was in. I put it in my 90 K5 and only did long tube headers, dual 2.5", and no cats. I have the 1 wire O2 in it now. I don't think it is getting hot enough. Do I need a 3 wire heated O2 to make it right and be able to tune it properly?

 

[odin]

Whats the trouble code???

 

[wayne]

Whats the trouble code???

Don't know. Didn't check. Yeah I know I should but I believe from everything I have read up on the O2 needs to be changed. I just want to confirm what I am thinking is probably right.

 

[b454rat]

Could be the sensor isn't getting hot enough. I just had duals put on my Blazer, manifolds, not cats, true duals and the check engine light doesn't come on.

I had a truck that I did put headers on, the O2 was in the y-pipe, but maybe cause it got hot enough the light didn't come on??

 

[odin]

I put TPI on my 79 GMC with full length headers and converted it to 3 wire O2.
Its a good idea for you to do the same. But it wont cause the MIL to come on if you dont. You need to check the code.

 

[Thunder]

Best thing to do is put a scanner on it to check the codes, and see if it is going into closed loop after the engine reaches operating temp. If it stays in open loop or goes back and forth between open and closed you need a heated 02 sensor.
If it stays in closed loop and you have operating problems the trouble is elswhere. Unless you just have a bad 02 sensor. wich usually throws a 13.

 

[wayne]

I ordered a 3 wire and will hook it up as soon as it gets here and see how it goes.

 

[eagle mark]

Mine runs fine with headers and a single wire O2...

 

[dyeager535]

Yep.

GM EFI/CCC systems commonly drop out of closed loop at idle from the factory, it's not a big deal.

IF the vehicle never goes closed loop, then you've got a problem. But mine goes closed loop as well, O2 is about as far back as you can get, it's past the collector.

The O2's respond pretty well to exhaust flow, you can watch on a scanner that it takes no time with any throttle input whatsoever to switch from open to closed loop on my setup.