Howler_GT

Removed the air restriction snorkel from the air box in our 91 Laredo.

Then turned my attention to MY 94 Sport.

After making the previous airbox mods (restriction removal and more air IN), it was time to address the IAT sensor. IAT sensor reads the temp of the air coming into the intake. The XJ's 4.0L has a few problems with this.

These problems stem from 3 things: location, location, location.

It is so far into the intake, it is no longer sensing AMBIENT air temp, which is what it was designed for. And it it between the CCV vacuum port and the cylinder head. This causes any oil fumes pulled from the valve cover to immediately hit the sensor turning it a lovely shade of black.

Time to relocated. Where? Air box, thats where.

Removed the airbox lid and took a step-drillbit in my cordless drill and drilled a hole that was just slightly smaller than the diameter of the sensor.I made this hole in the lower half of the airbox directly to the rear....more room outside box. Screwing it in should have ALOT of resistance. Used a wrench like I was installing it in the metal intake.
Once sensor had been relocated, I went about extending the wiring. Simple, snip and extra wire between. Making sure to get some sort of orientation color-wise.

I took the two lengths of wire (about 6-8" longer than I needed) and I chucked them up in my cordless drill and made a nice tight twist between the two. Connected everything together and routed the wires in some fresh black wire conduit.

Not to forget. I found a pipe plug to seal up the gaping hole in the intake.

Looks stock. Took it out for a spin. OMFG what a difference.
Way more umph to rear tires than the air box mods alone.

Time will tell. I have just filled up the tank and I will monitor if this has any change in my MPG. Probably will. Good? Bad? Dunno.

Howler_GT

BlueXJ

Thanks for that info. Will look for your report on MPG before I move mine as I have to find a place since I no longer have an airbox.

okcjeeper

Sweet can't wait to hear the report on over all outcome..I assume this is a newer model XJ thing and not on our older XJ's say 93 or older?

BlueXJ

OKC we have them but they are also called MAT or Manifold Air Temp sensors. They are on the top rear of the intake manifolds. Look up MAT sensors and you will find it.

okcjeeper

Ah gotcha...I know where that sucker is...All these acronyms get me stumped sometimes..

BlueXJ

That's what we old fawkers are for. Call on an old fart like me to help you find the outdated info.

fdulax13

do you have any pictures so i can check out exactly what it is your talking about?

also, is this kind of system possible using a K&N air intake with a cone? I'm guessing it would be the same, just drill a hole in the intake somewhere after the cone.

BlueXJ

Yes you are right on the placement of the sensor, and no I have no pics of a late model (2000) XJ with the sensor. Maybe someone can chime in here.

ren

Actually the older XJ's run BOTH. The MAP is either on the firewall, or on the side of the T/B. The IAT is normally located behind the T/B, about in between the #4&5 intake runners. This can help with idle issues too, on occasion.

Howler_GT

MPG update: Have been monitoring my MPG with this mod. I noticed a very slight increase. Roughly 1-1.5mpg.
Normally, I would say that the increase is almost unimportant...but with todays skyrocketting gas prices...ANY increase is important.

Please note: I also installed a 180* thermostat at the same time. I also altered the airbox.

These mods did not have the MPG monitored. The increase that I experienced may be due to a combination of the three mods....perhaps just one alone.

I examined the IAT sensor in our 91 Laredo. The sensor had turned jet black, due to the mounting location in the intake. Oil-fumed laden air hit it directly.

IF you do not relocate the IAT, AT THE VERY LEAST: removed and clean with a quality carb/choke cleaner. This is what we did to our 91. The Mrs. noticed a big change it the way it ran.

Howler_GT

BlueXJ

Thanks Howler. Will look into a relocation on my K&N setup.

okcjeeper

Ok I have a question on this flow restriction on the stock air boxes..Where exactly is this piece that you remove? Is is in the actually flex tube or is it in the air box lid? If it's in the actual tube then I am going to assume mine has already been removed..I took the tube off and examined it flex it flattened it and what not and there seems to be nothing in it..So I am curious where this restriction is located..

BlueXJ

Don't expect an answer from me. My airbox is long gone and the flex tube as well.

Howler_GT

The restriction is in the airbox lid.

It can be pushed out from the inside to the outside (airflow direction)

Sorry, should have been more clear.

Howler_GT

okcjeeper

No worries I was for some reason thinking it was in the tube..I'll remove it and see how well the air flows now...May not need to put that rustys air tube in then...