7747 to 7427 swap complete?

[satinblack91]

So...the swap went very smooth and have to say, im very impressed with the way it runs open loop. The only problem is, it wont go closed loop. I'm getting the O2 failed code. I had installed a heated O2 several monthe ago, but in the header. First, I'm going to double check the O2 pinout. But, I had read where 95 trucks had the O2 mounted further back in the exhaust. I do have a bung in front of my cat. Would that be a better location for the 7427?

[dave w]

So...the swap went very smooth and have to say, im very impressed with the way it runs open loop. The only problem is, it wont go closed loop. I'm getting the O2 failed code. I had installed a heated O2 several monthe ago, but in the header. First, I'm going to double check the O2 pinout. But, I had read where 95 trucks had the O2 mounted further back in the exhaust. I do have a bung in front of my cat. Would that be a better location for the 7427?

Just before the Catalytic Converter is an excellent location for a 3 wire heated O2 sensor using the '7427 PCM.

dave w

[Fast355]

Just before the Catalytic Converter is an excellent location for a 3 wire heated O2 sensor using the '7427 PCM.

dave w

I agree however 02 placement is not going to be keeping him out of closed loop.

[JeepsAndGuns]

I am running a 7427 and I have my heated o2 a few inches behind my header collector. It has not caused any issues I am aware of.
I would double check the wiring, the grounds, and all proper connections on the pcm.

[satinblack91]

Thanks guys for your input. I had the O2 signal pin a spot off. Everything is working well and datalogging. Will still move my sensor back when I put the other motor in. And, for those that are apprehensive about doing this swap as I was...it is very simple. It helped me to keep notes and a checklist.

[Fast355]

Thanks guys for your input. I had the O2 signal pin a spot off. Everything is working well and datalogging. Will still move my sensor back when I put the other motor in. And, for those that are apprehensive about doing this swap as I was...it is very simple. It helped me to keep notes and a checklist.

I wrote up a swap notes list on thirdgen.org years ago when I first swapped to a 7427. Its really not bad at all. Took me about a solid hour of comparing wiring diagrams to get the pins in the right place. With notes the actual swap only took about 30 minutes. Comparing to an 0411 swap its a cake walk.