No More Air Injection Pump?


I happened to run across something earlier today that a national parts store sells that supposedly will work for our face-lift XJSes. It is basically a bolt-in idler pulley to take the place of the air injection pump, should an owner decide to get rid of theirs. It apparently is not illegal to do this, except in the state of California. If this elimination should adversely affect emissions levels, I wouldn’t be worried b/c my cat, Superblue, is a '94, and cars here in Texas that are 25+ years old do not have to pass the emissions part of the annual inspection. Question, though, would there be any advantage in not having the air injection pump, in terms of performance, horsepower and/or gas mileage? :thinking: btw, note that this part will not work for the '95-'96 MYs (i.e. AJ16 engine), as it has an electrically-operated air pump.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #2

Can you post a link to a pic of that item?

(Doug Dwyer) #3

Your state may not know or care but I’m pretty sure it’s a violation of federal law. Not that the men in black are on the prowl for people removing air pumps, either. So, it’s a bit academic.

In my experience, it is so slight that you’d probably never feel it.

Most remove the pump to de-clutter the engine bay or because it has failed and they no longer need it.


(Greg) #4

Whenever you remove another pump/pulley the engine has to turn, and the weight of that part (pump in this case) you improve performance and gas mileage. But we’re talking negligible. Maybe 3 HP, 1/2 MPG if I had to make a guess?

I removed my air pump, but mainly to remove extra parts and hoses and wires from the engine. I prefer less junk in that engine bay, much easier to work on. Removing the air pump wasn’t too bad, the time consuming part was plugging those holes from removal of the air rail.

I also removed my A/C, so I didn’t need a pulley where the air pump used to be. Eventually when I need a new alternator, I’ll put one where the air pump used to be, and put back the A/C.


It’s made by a company called “Proform”. Technically, it says it fits a 302/351 Mustang in the description, so I guess it will also fit our pre-'95 MY face-lift XJSes (4.0)? At least, when I put in that description of “my vehicle” it pulls up that part under “air pump”. :thinking:

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #6

Ah, you’re dealing with a 4.0. So the serpentine belt pulley might work for you.

(JimD in Alabama) #7

slight excursion from main thrust of topic - - but wonder why that part says it cannot be shipped to California ? Certainly not because of emissions

(Carl Hutchins, Jr. ) #8

Irony, Yup. precisely…


(Ed Sowell) #9

Not sure, but it probably is because it’s against federal law to remove emission control devices. At a more practical level, the smog test includes visual inspection and removal would surely be noticed.

OTOH, California requires manufactures to provide 3rd party certification of certain kinds of equipment, e.g., water filters. Some manufacturers choose to not bother with getting certified and instead block CA sales.

(Carl Hutchins, Jr. ) #10

In re yours:

  1. Yup. Yet a past lister, Id to remain unpublished, reported the removal of the pump on an SII. Neatly. The SMOG techn ever noticed it’s absence… Passed.

  2. That is it. Many perfectly acceptable products, just NA to us. OTH, some junk not either!!!



His view of that area must have been blocked by “Mr. Benjamin” :money_mouth_face: … (j/k, Cadman! :laughing: )

(Carl Hutchins, Jr. ) #12


It was in the era that shenanigans via Benjamins was feasible. Although under cover BAR folks would test the rep. Bait and bucks!

But, I am sure the lister I had in mind would have none of that.

I recall a local shop had a little car in a corner that could stand in and pass.,

Not for me, no way, no matter my disgust at the flaws in the SMOG program…