PAIR valve removal???

[donutfj80]

I've searched and can't find the answer. Is it OK to remove the PAIR valve and put the O2 sensors in the holes in the exhaust manifold. Both O2s are pre-cat, and a custom exhaust system will replace the old setup. Will I damage anything over time, moving the O2 sensors and removing the PAIR valve?

 

[Bearcat80]

Nope. The "pulsed air injection valve" is used to inject air into the exhaust when the engine is cold or decelerating to reduce emissions, i.e. the "solution to pollution is dilution". You won't be putting more junk in the air, it will just be less diluted. No harm to the cats , as they will still have to burn off the same amount of unburnt fuel, it will just happen later into the warmup cycle.

 

[donutfj80]

OK, but how about putting the O2 sensors in the manifold? In the holes from the tubes.

 

[donutfj80]

I read somewhere here, that someone moved the O2s to the manifold. I don't recall the reason and can't find it either.

 

[donutfj80]

Anyone on the O2 question

 

[IBCRUSN]

Is it okay? Legally, no especially if smog testing is required. If you disguise it by installing a '95+ heater coolant tube most will never know.

Here ya go...

https://forum.ih8mud.com/80-series-tech/235754-93-one-o2-sensor.html

Shows my truck when I removed the PAIR valve. Pics are in post 11.

 

[zx9r]

donut -- refer to this thread or maybe ebag will check in as he seems to be very knowledgeable on the whole emissions topic.

https://forum.ih8mud.com/80-series-...ete-1996-lx450-exaust-system.html#post5125264

 

[zx9r]

I was considering this before replacing my exhaust system. Still might if I hear good things before it is too late to change the spec for my order from Baktash at EMSPowered. At the time, decided I have too much going on and better to just get things working normally rather than get caught up in modifications. But still would very much like to clean out some of the junk under the hood...

 

[donutfj80]

Thank you IBCRUSN! That is what I started to read years ago and never finished.

 

[Ebag333]

donut -- refer to this thread or maybe ebag will check in as he seems to be very knowledgeable on the whole emissions topic.

Gotmud also has posts on removing the PAIR system scattered around the forum.

If I owned an 80 with the PAIR system, it'd go away.

 

[IBCRUSN]

Thank you IBCRUSN! That is what I started to read years ago and never finished.

You're welcome. Do you have to participate in the smog testing out in western NY? If so it would be wise to obtain the '95+ coolant line, remove the vac hard lines on the front of the head and plug the line under the upper manifold. Explaining the plug in the air cleaner could be as easy as saying it was an intake silencer box attachment and will be in the way of your future dual battery setup. It all depends on the shop that performs your inspections.

 

[MARLIN375]

I ditched the cat and the PAIR assembly a year ago and moved both sensors into the bungs on the manofolds.

Perfect code free operation so far, and my sensors still look like new, not like when they are in service behind your tire for a year.

 

[donutfj80]

No smog test for pre-95 around here. You should see some of the s*** on the road up here, It's almost like if you have headlights and brakes your good. I passed with mixed years, grooved to the belts swampers and a cracked windshield. I'll show off the new cat-free exhaust and O2 move in a couple of days.

 

[cool breeze]

Where did the people who junked all the system use to plug the large hole on the airbox? Im tired of the sexy duct tape look but cant find a large enough bypass or vacuum cap anywhere.

 

[ybhc]

Where did the people who junked all the system use to plug the large hole on the airbox? Im tired of the sexy duct tape look but cant find a large enough bypass or vacuum cap anywhere.

I (forcibly) threaded a 1" brass nipple into it and screwed on some cheapo aluminum cap.

looks better than electrical tape, though still absurd.

 

[Sc0-]

I also performed the mod a year or so ago, plugged the air tube on the airbox with a PVC plug that fits snugly inside with a hose clamp. It has melted some but still gets the job done. I also stayed with the coolant hose as well. With the PAIR removed, relocated 02's, blocked off the EGR, and bypassed EGR temp sensor... It still passes the emissions test and has the OEM cat converters.

 

[IBCRUSN]

Where did the people who junked all the system use to plug the large hole on the airbox? Im tired of the sexy duct tape look but cant find a large enough bypass or vacuum cap anywhere.

Head to Lowe's or HD's plumbing section and look for the appropriate sized (1" IIRC) expanding rubber plug. I've had that style plug installed since I removed my PAIR without issue.

Expanding Pipe Plug

 

[Frankencruiser]

When I ditched mine I just cut off about 1.5 inches of the pipe coming off of the airbox and filled the end with RTV. I planned to buy a rubber plug, but the RTV is holding up just fine.

 

[GREATCRUISER]

west marine have these for $1.

 

[IBCRUSN]

west marine have these for $1.

That would work as well. I hadn't even thought of a boat plug but being in KS we don't have many marine stores.