Broken... something?

I foolishly thought my '92 xj would be fine going over a sidewalk and a bit of grass, especially since the sidewalk was in fact flush with the road. But, of course, this bit of offroading action tore something out from underneath my car, which dragged along in the wheel well for a bit before the top half shattered into a million pieces. What I am staring at right now is the lower half... the whole thing was shaped like a gigantic pill, the cylindrical kind that are often filled with gel. It's black. It was connected to a tube on the passenger side wheel well. The tube goes off somewhere towards the radiator. I have no idea what it is and where it connects to and didn't even know it was a part of my car. However, I don't plan on driving my lovely piece of junk until I know what the hell that thing is. So any help is VERY much appreciated. Thank you!

Sounds like the vacuum reservoir bottle. It was located inside of the front bumper on the passenger’s side. It will affect things like idle speed, cruise control, emissions, a/c control, etc.
Yup, you probably should replace it.

Sounds like the vacuum bottle - looks like this?

Yucca-Man said:

Sounds like the vacuum bottle - looks like this?

Click to expand...

From your first post, it sounds like it looks like a pill/capsule, as shown . . . but, just for reference, it could also look like a ball about the size of a softball (as on my XJ). If you decide to get one from the auto wrecking yard, I think the round one will work as well as the capsule shaped one. From the description you gave, you said that it had one line going to it . . . mine has 2, so you may find another one loose somewhere.

I say pitch it, I removed the vacume resevoir when I redid all the vacume lines in my engine. It's one of those extra parts that DMC likes to put on XJs. I run a 4.0L engine, with no cruise. There isn't much to the vacume system period. with the simplified lines in my jeep, I find that there is less places for vacume leaks to spring up.

Just my opinion, but if it's already gone, is it worth it to you to track down and buy a new one?

Bones

Beached Bones said:

I say pitch it, I removed the vacume resevoir when I redid all the vacume lines in my engine. It's one of those extra parts that DMC likes to put on XJs. I run a 4.0L engine, with no cruise. There isn't much to the vacume system period. with the simplified lines in my jeep, I find that there is less places for vacume leaks to spring up.

Just my opinion, but if it's already gone, is it worth it to you to track down and buy a new one?

Bones

Click to expand...

It might be worth it if you have cruise control, or if you have an older Jeep with a vacuum axle disconnect, otherwise you may run out of vacuum on long climbs and the like. It can be really annoying to be going up a long hill in the snow and have it pop out of 4WD just before you reach the top! If all it controls is the heater, you can get away without it, because the worst it will do is switch to defrost occasionally.

Beached Bones said:

I say pitch it, I removed the vacume resevoir when I redid all the vacume lines in my engine. It's one of those extra parts that DMC likes to put on XJs. I run a 4.0L engine, with no cruise. There isn't much to the vacume system period. with the simplified lines in my jeep, I find that there is less places for vacume leaks to spring up.

Just my opinion, but if it's already gone, is it worth it to you to track down and buy a new one?

Bones

Click to expand...

It also controls the defrost/heat option. I've got a leak somewhere and only have defrost. In case you've never noticed, you get worse gas mileage on defrost....or at least mine seems to.

Sarge

Sarge, yer pullin' our legs, right?

I'm sure you know that the reason you're getting worse gas mileage is because you have a vacuum leak, not because the heater is blowing air at the windshield.

Fuel/air mix is controlled by the ECU, based on several inputs but particularly on the O2 sensor. If you hahe a vacuum leak, the intake is sucking air that's not being controlled by the throttle body, which means the TPS sensor input is slightly faulty. The O2 sensor reads a lean mix (too much air for the amount of fuel being delivered), so it calls for a richer mixture.

More fuel ==> worse economy.

Eagle said:

Sarge, yer pullin' our legs, right?

I'm sure you know that the reason you're getting worse gas mileage is because you have a vacuum leak, not because the heater is blowing air at the windshield.

Fuel/air mix is controlled by the ECU, based on several inputs but particularly on the O2 sensor. If you hahe a vacuum leak, the intake is sucking air that's not being controlled by the throttle body, which means the TPS sensor input is slightly faulty. The O2 sensor reads a lean mix (too much air for the amount of fuel being delivered), so it calls for a richer mixture.

More fuel ==> worse economy.

Click to expand...

Eagle

I certainly do not want to discount ANYTHING that you have to say, but doesn't the A/C compressor come on when the defrost is selected?

Humbly,
8700XJS