Non emissions heders...

[87BrnRsd]

I have an 87 K5 tbi, with air injection. I bought a set of non emissions headers. Will it hurt anything (computer) to just put the non-emissions headers on and forget about the air injection? I know, I know....its not legal to do so. But, I only drive the truck to and from the trail now and inspections are not a problem. I will be welding in an 02 sensor bung though cause I know it wont work without the 02 sensor. Thanks.
-Harrison

 

[wicked jester]

My '88 had the air tubes as well, when I put my headers on I just left them off (no inspections here) It will not change or hurt anything.

 

[dyeager535]

Probably going to be wanting a heated O2 sensor as well.

No problems with AIR not hooked up on my TPI setup.

 

[87BrnRsd]

Thanks guys....thats the answer I was looking for....
-Harrison

 

[R77K10]

a heated sensor would be the best, one of the three wire ones

and A.I.R. system is completely a stand alone separate system

no problem there at all

good luck

 

[87BrnRsd]

What would the difference be between a heated 02 sensor and just putting in the same one that is on there now? Since im removing the air...the heated 02 sensor would start reading the exhaust gas immediately and get rid of the rough running condition when the engine is below 160 degrees. Im guessing without air...the rough condition before the engine warmed up would be exaggerated? So, I am I right about this? Could I do without the heated 02 sensor since its like $100 and thats not really in my budget right this moment....
-Harrison

 

[wicked jester]

It will just "trick" the computer into thinking it is at a warmer temp then it really is, so it cuts back the enrichment makeing it easier on fuel. I have full length on mine with a non heated o2. Never really had any issues with it although it will light the CEL on occasion but its no big deal.

 

[87BrnRsd]

It will just "trick" the computer into thinking it is at a warmer temp then it really is, so it cuts back the enrichment makeing it easier on fuel. I have full length on mine with a non heated o2. Never really had any issues with it although it will light the CEL on occasion but its no big deal.

Ahh, i got ya. I figured it would just make the computer think its warm so it would run better from startup. I think ill just keep the current one until I have sufficient funds for a heated one. Thanks everyone for the help!
-Harrison

 

[dyeager535]

A heated O2 is not "tricking" anything. O2 sensors need to be at a certain temp to work correctly, moving the sensor further from the engine, or decreasing the amount of exhaust it sees (headers, or duals in an originally single setup) means the sensor isn't getting as much heat. You will see it drop out of closed loop operation more often, if it ever gets there in the first place. You may not notice that it's open loop without watching ECM operation, but you will in economy, since it will default to a "known safe" mixture.

An AFS-74 (that's a delco number, you should be able to cross that to a GM part number) from gmpartsdirect.com can't be more than $60, can it?

 

[87BrnRsd]

A heated O2 is not "tricking" anything. O2 sensors need to be at a certain temp to work correctly, moving the sensor further from the engine, or decreasing the amount of exhaust it sees (headers, or duals in an originally single setup) means the sensor isn't getting as much heat. You will see it drop out of closed loop operation more often, if it ever gets there in the first place. You may not notice that it's open loop without watching ECM operation, but you will in economy, since it will default to a "known safe" mixture.

An AFS-74 (that's a delco number, you should be able to cross that to a GM part number) from gmpartsdirect.com can't be more than $60, can it?

Hmmm...interesting. What will this do to the performance? Thanks for the info...
-Harrison

 

[1979jimmy350]

if you are removing the AIR you need to mess with the computer chip a little then, becasue when the air pump engages the computer changes the reading that it gets fromt he o2 sensor to compensate for the extra air in the exaust

 

[87BrnRsd]

Your the only person on this board ive ever heard say this. Everyone else said it doesnt affect the computer. Doesnt the air system only come on when the truck is cold...shouldnt make a difference once the truck and 02 sensor are warm.
-Harrison

 

[wicked jester]

I never changed anything with mine once the headers were on. I nevr bothered with changeing to a heated o2 and have not noticed anythig odd yet. Has been 5 yrs like this now.

 

[dyeager535]

I checked into this because it *is* verified on at least some TPI systems that O2 sensor interpretation is affected when AIR is commanded by the ECM.

I couldn't find anything showing that the '747 runs AIR the same way as either(both, or?) the '165 or '730. Almost certainly the difference in emissions between cars and trucks unless someone here finds the same thing in the '747.