Does your Cherokee suddenly overheat?

I see that question a lot. The story basically goes something like this:

I was out on the interstate today, going about 75mph in 90 degree heat with the AC on full blast (probably with a lift, bigger tires, and stock gearing), and I noticed that my temp gauge was a little over 210. Close to the 220 mark. I know that normal operating temperature for my 4.0 is between 205 and 210, so I wasn’t all that concerned. Then all of a sudden my temp gauge spiked to 260, the instrument cluster beeped at me, and my check gauges light came on! What happened?

Well, what happened is that your instrument cluster temperature gauge is a dirty little liar, that’s what. And as far as I’m concerned, it’s the worst possible liar in that it doesn’t tell you how serious things are until you are well past time to take action. In other words, you were having problems looooooong before your check gauges light came on.

So let’s start off by talking about where that gauge gets its’ readings. In 1996 and older cherokees, there were actually two separate temperature sensors–one in the thermostat housing on the front of the engine, and another one in the back of the block. The front sensor was for the engine computer, and the rear sensor went straight to the temperature gauge in the instrument cluster. If you have one of those older cherokees, then the rest of this article doesn’t apply to you. In fact, I’d be shocked if you were having this “sudden overheating” problem in the first place.

In 1997 (or possibly 1996, since they were the first OBD2 XJs) they ditched the rear temperature sensor. In the 97-01 models, the engine computer (Powertrain Control Module, PCM) reads the resistance value from the engine coolant temperature sensor. The ECTS is an inexpensive sensor because it is essentially just a variable resistor that—wait for it—varies the amount of electrical resistance depending on what temperature it is.

Here’s a handy chart that shows what the factory sensor’s resistance is at specific temperatures. You can use this chart to determine if your sensor is bad, by the way.

As I mentioned, that resistance is read by the Powertrain Control Module. The signal wire for the ECTS goes directly to the PCM. It goes nowhere else. It’s circuit K2 in the factory service manual, which you should buy right now if you don’t already have one.

The PCM then sends out the calculated temperature via the CCD bus. CCD is Chrysler’s intra-vehicle communications protocol, similar to CAN bus.

The instrument cluster reads this value off the CCD Bus. Here’s the diagram from the factory service manual that shows how this communication works:

As you can see, the temperature gauge in the instrument cluster has no direct communication with the ECTS. It only know the value that is put out by the PCM.

You know what else can read the value put out by the PCM? Every single OBD2 code reader on the planet. And as a bonus, with Chrysler vehicles (like the 97-01 XJ), it reads it off the CCD bus:

I bought a ScanGauge II in like 2005 and have used it extensively ever since. There are much better options out there today–like the UltraGauge–but I have it so I use it. If you just want something for this test, a cheapie OBD2 bluetooth adapter and a free app like Torque will do just as well.

Here are my readings from yesterday. It was 90 degrees outside, I had the air on full blast, and I was trucking down the interstate at 80mph with a 3″ lift, 33″ tires, and stock gears.

Here’s a lovely comparison of the same PCM signal being displayed as 229F by the ScanGauge, but being interpreted by the temperature gauge as a touch under 220:

And here we have the gauge happily reporting 220, still, yet the PCM reporting 245:

And this is after I’ve been off the interstate for a few minutes with the AC turned off. Scangauge reads 225, temperature gauge reads about 215:

From my experience, the temperature gauge reads fairly accurately up until about the 210 mark. After that is when it starts to lose its’ mind.

The cooling system is not overly complex so there are not a whole lot of things that could be causing higher than normal temperatures. Maybe I’ll do a write-up on what to do next, but this post is really more about pointing out that the temperature gauge is not a precise reading once you go above normal operating temperatures.

(okay, technically the hash marks from 210-260 are 12.5 degrees, meaning the 220 mark is really the 222.5 mark, but even in that case the 245 reading should have been right on top of that hash mark before the 260.)

I made a thing

I continue to absolutely love living in the future.

I am a cheap bastard. My cars are old. My house is old. My guns are significantly newer, but they’re not expensive. The most expensive gun I own is the AR10 I built and most of that is because AR10.

My “long range”* rifle is a Remington 700 AAC-SD with the factory trigger and a $350 scope. My carry gun is a Glock 23 I bought 10 years ago. My IDPA gun is an M&P9 with an apex trigger but that’s it.

So when I bought a spotting scope, I went with something super cheap: The Emarth 20-60x60AE

But, well, it kind of sucks, being that it’s so cheap. So since I have a 3D printer and you can get a Logitech C270 for $15, I decided to make two cheap things way, waaaaay better:

I’ll let you know how it works out at the range. Or not. I’m semi-retired from blogging ūüôā

*Now that I’m really starting to get in to it, the R700 doesn’t really qualify as long range anymore. Need moar Creedmoor.

Huh… hadn’t thought about that…

One of my friends just got his paperwork back on a silencer that he submitted almost exactly 1 year ago (360 days, do be exact). ¬†Judging by the comments on his Facebook post, roughly a year ¬†turn around on NFA paperwork is not unusual these days. ¬†Oh, and for the record, this is far from his first NFA item, so 1. he had all his paperwork in proper order, and 2. I can’t really see any reason that this one didn’t get rubber stamped.

So…. plan on a year + $200 for permission to buy a can. ¬†This might not be a problem if you’re buying from a store. ¬†Just make sure that the shop has been there a while, and there’s a pretty good chance that they’ll still be there and they will still have your can in the back. ¬†Buying from an individual? ¬†That’s a bit… different.

Basically, how things currently stand, I hope you like that suppressor for the long haul. ¬†Not many folks are going to buy that off you when they know that it’s going to be a year before the transaction can actually take place.

Oh, and on top of that, if you need to move? Yeah… you have to make sure that the address gets changed in the proper amount of time… assuming that you’re moving to a place where the local LEOs are ok with you owning one.

AR10 Mag Pouch for PMAG20 and PMAG25

So I did a thing and built an AR10. I bought the lower and about twenty PMAGs (a mix of 20 and 25 LR/SRs) in late October of 2016. You know, back when Hillary! was inevitable and before the Russians hacked the election. Or something.

Anyway, I built the lower into a 16″ AR10 in .308. Then I realized that I had all these magazines and no mag pouches, which isn’t really a big deal because it’s not like I’m humping a ruck through Tora Bora, ya know? I go to the range and back, and that’s basically my use case.

But, you know, the NorKs could EMP us and then what?! I’d be carrying my PMAGs in my pockets?

So I searched high and low to find a mag pouch that fits the PMAG25. I almost bought a set from Condor or somesuch, and it turns out that steel AR10 mags fit but the PMAGs decidedly do not.

The NRA Annual Meeting in Atlanta was upon us, so I decided to wait until then to find someone who made what I wanted.


That’s the Tactical Tailor Fight Light 7.62 Double Mag Panel. Yeah, it says 20rd but those are PMAG25s in there. Works for both!

I figured I’d make my annual blog post be something useful for someone else.

Random gun pics are cool, right?

Presented without comment, the contents of a pistol case in my house the other day: a Coonan and a .45 HiPoint.

Yes, that is a factory paint job.

I… wow…

So, one of my seriously left leaning friends that is anti-gun posted the following picture with the comment “Not what I like to see at work……”

Me, being the smartass that I am, commented “The fact that both the definition for rifle and shotgun are wrong?”

To which she replied:

“Well, I wouldn’t know, I just see guns like that and all I can think is, “how many children could that gun kill before the police could arrive?” I just want there to be fewer of them around people who don’t play well with guns.”

So… apparently, she gets upset merely seeing pictures of guns on a page in the more sterile environment possible.

I knew that this level of hoplophobia existed, it’s just jarring to actually see it in action.

Well… that went differently than expected

Dennis at Dragon Leatherworks hosted the Second Annual East Tennessee Blogger Shoot this past weekend. ¬†I’ll try to do a proper write-up of it soon, but I wanted to make sure to mention a couple things.

I actually went with the desire to shoot a little .32acp derringer and a Ruger LCR in .357mag.  Both of which I knew were going to be there.

My desire was to fire them and get the desire to buy them out of my system. ¬†“The more you know about guns, the less you want a derringer,” and “no, you really don’t want a .357 snubby, just get the .38 and save some money” are statements I’ve heard many, many times.

Actually firing them has not done this.

Shooting the derringer just made me giggle and have a desire to keep feeding it.

The LCR with full power .357mag? ¬†“I cast FIREBALL!”

I probably need help.


So, apparently, everyone is talking about¬†TN’s governor signing a bill into law that would make silencers legal here.

You’d think I’d be excited over this, but… meh.

The thing is that silencers were already legal here.

The previous state law stated that silencers were illegal, unless you were in compliance with the NFA. ¬†Yes, it was an affirmative defense instead of “yup, it’s legal,” so, in theory, a cop could arrest you for owning a silencer, book you, and then you get to show a judge the paperwork, and he then lets you free. ¬†To the best of my knowledge, this has never happened. ¬†Pretty sure that just about all interactions have basically been “you got paperwork for that?” “Yup, right here!” “cool, thanks.”

The only positive I see is that, if the Fed actually passes the Hearing Protection Act, there will be no ambiguity over how TN would handle possession of silencers. ¬†Of course, that’s a bill that hasn’t actually seen movement in the Senate since before Trump actually took office…

By the way, some news reports have stated that machine guns and short barreled rifles are illegal here. ¬†Same thing applies to them. ¬†If you have proof that you have your tax stamp, you’re cool.

Elio’s having problems. This is my shocked face.

Recently, I read that Elio was saying that it needed more money to make some prototypes, do testing, and actually start producing their nifty little car.

A lot more money.

Somewhere around the lines of $376 million.

For those of you that haven’t heard of Elio, they’re a company that was created in 2009 to produce a reverse trike car with a 55hp engine that should be able to reach a top speed of “over 100mph,” and a fuel efficiency of 84mpg highway (according to their site). ¬†Currently, the base price is $7450. ¬†They started taking pre-orders in 2013, with projected production in 2014… and then 2015… or was that 2016? ¬†Maybe 2017… nope, 2018, and this time we mean it!

Oh, and the Louisiana parish that has helped secure them an old GM plant to produce these things is now starting to ask some very pointed questions.  Apparently, this company has been holding onto this plant for 3 years, and, after promising to add 1500 jobs to the area, there are currently 28 on the payroll.

I might have written this off as another start-up company that simply bit off more than it could chew, except it’s remarkably similar to another company in the 1970’s. ¬†That company was the 20th Century Motor Company and the Dale.

If you’re not familiar with the Dale, Jalopnik has done a wonderful job of chronicling it here, as has Car & Driver here. ¬†The quick description is that 20th Century Motor Company was setup to produce the Dale, which was supposed to be a reverse trike car that had a 40hp engine. ¬†It would reach 85mph, see 70mpg, and cost $2k (a bit over $9k in today’s money). ¬†The media at the time lapped it up, and even the Price is Right had it as a possible prize.

Of course, the entire thing was a scam. ¬†The vehicle that was pushed onto the display floor on the Price is Right wasn’t a functioning vehicle, and it was discovered that the prototype that they used in many of their promos didn’t have a steering wheel, or a gas peddle, and the engine was actually from a lawn mower and wasn’t hooked up to the transmission.

The owner of the company fled with the money she had stolen from the company, and was eventually caught years later.  Oh, I think I forgot to mention that she was actually using a false name at the time, and was wanted on several money laundry charges.  It really is a fascinating story.

So… let’s check off similarities between the Elio and the Dale:

Both are three wheel cars in a trike configuration

Both claim to be able to squeeze great performance out of small engines (“>100mph”/85mpg/55hp vs 85mph/70mpg/40hp)

They’re not far from the same price, adjusted for inflation (starting at $7450 vs $9k)

Both started business during a gas crisis. ¬†The Dale had the 70’s gas crises, and Elio was started when $4/gallon prices were not unusual.

Both set production deadlines that they weren’t able to meet. ¬†The Dale saw many “delays,” and Elio has consistently pushed their production time back since 2014.

Both have taken in millions in both investment money and pre-orders with no working vehicles produced. ¬†Yes, there are YouTube vids of people driving Elios, but you’ll notice that they all state that that prototype doesn’t have the engine that will be in the production vehicle.

Both are claiming to use parts from vehicles from other manufactures, but aren’t actually connected to those manufacturers (as far as I know).

I’m not saying that the Elio is absolutely a scam, and they will never produce anything, but that’s the way I’m leaning until they actually come out with something.

Uh oh…

Looks like Wizard has some explaining to do