4.2 fuel injection & removing the air pump

XK-Engine
1

I’ve got a '86 XJ that is fuel injected. I want to remove the air pump. By doing so, am I going to screw up the fuel metering? If I’m posting in the wrong place let me know.

Thanx
Mark

2

Won’t change fuel metering at all.

Cheers
DD

3

Then what is the purpose of the O2 sensor?

4

The O2 sensor measures oxygen in the exhaust. But here’s the thing…

Output from the air injection pump is injected into the exhaust ports only when the engine is cold. After the coolant reaches xxx-temperature (about 150ºF I think) output from the air injection pump is routed to the air filter canister. This is controlled by a temp switch on the water rail and the air injection switching module…which operate the diverter valve on the back of the air pump.

Meanwhile, the still cold-to-warmish engine is running in ‘open loop’ mode …no input from the oxygen sensor, preset fueling map.

So, by the time the engine is operating in ‘closed loop’ fueling mode the air injection pump output is being diverted harmlessly to the air filter canister. Thus the air injection doesn’t do anything to fuel metering

Cheers
DD

5

Will the lack of oxygen lead to quicker convertor failure? First the exhaust mixture will be a little rich, i think that’s better than lean. Warmup of the cats takes longer and the fuel won’t be able to burn of-?

When warm the airpump should not do anything, just in the warmup phase to cut emissions by heating the converters up quickly, so far I understand the process.

David

6

Thank you Doug. At this stage of the game, the air pump is the least of my concerns.

Thanx again,

Mark

7

Plausible, or at least ponder-worthy. But in actuality it doesn’t seem to be a concern; never heard of any cat converter issues as a result of removing the air injection

Cheers
DD

8

Max,
I consider the air pump mount a work of art (not the air pump) as such I would be a buyer for the mount. I have a “boat load” of parts as in alt, starters, a/c, injectors…be glad to trade or just buy.
Mitch 970 779 0456 Phoenix

9

I may have a couple of air pump mounts, i believe it’s also necessary for the A/C compressor - if memory serves. I also have a TIG welder, cutting torch or bandsaw) 5/32" Steel plate, & and a drill press; I could also make one for you as well.