gogmorgo

Oops... wasn't expecting that to be 45 minutes long... so much for going to class.. Lots of interesting stuff in there. I'll admit I never really was much into Jeeps before I bought my MJ, and hadn't really looked into Jeep history. Probably my best ever calculus class, heheh. Something I did notice at the end of the credits: "Created by the Canadian Government." Y'all are welcome!

Yeah, it really does sound a lot like passlock. Is the security light on/flashing in the dash?

My running average is in my sig. Right now I'm not doing as well as I was back in September and October because winter. 91 4L HO, automatic, Mostly that's cityish, where I've been getting typically around 13 mpg. A couple times I dropped to 8 because I spent a bunch of time pushing through deep snow in low range and being very stuck. On the highway I usually do 16-17, best I've done ever is 19.3. All on the US gallon. All the gas I've run through her except the tank I got the day I bought her and a couple $20 bumps (those tanks discluded from total) is on fuelly.

Not true. There's an efficiency point that moves around depending on load and a few other variables. Usually it's significantly below peak torque. Best mpg I've ever had was cruising at around 1800 rpm. If I go much faster, my fuel economy makes a steep downward curve. onlyinajeep726, where did you get that list and what exactly are the numbers? As in where do they come from / how were they determined? For the engine, the torque peak RPM is absolutely the most efficient operating speed. Torque is mundanely defined as "horsepower per revolution." so the engine speed that produces the most power per revolution is the most efficient engine speed. [...]sitic losses above that speed. It's not that I don't believe your evidence, it's that I know your conclusion is flawed and I'm still uncertain how your evidence supports it. Think of it this way. When you're accelerating, you have the gas pedal pushed down. When you hit your desired speed and want to stop accelerating, you have to lift off the gas pedal. The throttle closes, less air gets in, and to maintain a proper fuel/air mixture, fuel flow is also reduced. Suddenly you're using less fuel, and you didn't change your engine speed at all. You knew that already. Torque, as you know, is dependent on engine speed, and remains constant so long as the engine speed does. Horsepower, on the other hand, is the rate at which the engine converts energy into motion. As you know, horsepower peaks don't occur at the same point as torque peaks. The amount of power an engine puts out is dependent on the amount of power consumed by the load, or in other words, power is the energy required to maintain a certain engine speed at a certain load. All the energy in the engine comes from fuel. More energy required means more fuel required. Torque is simply a rotational force, and really doesn't have much to do with how much energy is converted. If you have very little load on the engine, you consume very little fuel. If there's a big load on the engine, you use a lot of fuel. No matter where you're at in the rev range. Torque, as I said, is a rotational force. It follows that peak torque is obviously the point where your engine is making the most force. If I'm walking, my muscles are applying less force than when I'm running, mostly because when I'm running I bend my knees a lot more which gives me better leverage. Actually, if I'm pushing against something I end up in a position very similar to when I'm running, because I can better apply torque that way. As I'm sure you know, walking takes substantially less energy than running, even though there's much lower torque. The point I'm making is that you can waste a lot of energy just trying to maintain a high level of torque. Yes, cars and people aren't quite the same, but the physics of force and energy don't change. As far as this rule of max torque= max efficiency, several hundred years of physicists say otherwise, and it completely goes out the window with my experience. My best fuel economy in my MJ was a there-and back trip along the exact same stretch of road (massive tailwind wasn't a factor), at around 1800 rpm (massive tailwind wasn't a factor) at roughly 55mph. I've made the exact same trip going different speeds, from 60 to 80 mph, and never managed within 20% of that one best. The next best fuel economy I've had was only about 7% down from best on different roads but running at the same speed. Another, even more drastic example of the lack of correlation between peak torque and peak mpg's is in my dad's old 3.4 Impala with a 4-speed auto. He gets his best fuel economy around the 50-55 mph mark in overdrive. Something like 36mpg. Peak torque is around 4000rpm. Don't even try telling me he's anywhere close to that in overdrive at 50 when second gear is good for 90+mph (which I know from being a teenager). I've seen you say peak mpg is at peak torque several times in the past, giving the same arguments, even down to the huge snow tires, yet I have still have trouble seeing how they support your conclusion. The larger tires are a nice lesson in gear ratios and drag, but don't have anything at all to do with your argument. Now, I'm not saying that lower rpm always equates to better fuel economy (my dad is still perplexed at how I manage to get better fuel economy in his van than he does when I drive it harder than him) or that it's not possible for peak economy to occur at peak torque, but if it does, it's merely a happy coincidence. The maximum fuel efficiency point is where the energy required to maintain engine speed at a constant load is at a minimum. As speed increases, energy requirements go up. As speed decreases below peak torque, torque goes down. If you plot the two on a graph, where the two lines meet is peak economy. At higher engine speeds, you're just wasting energy making it turn faster. At lower engine speeds, you're not making enough torque to generate enough power to keep going without adding more fuel. You knew torque came into it somewhere, right? Also, as load increases, the point moves upwards, towards peak torque (I honestly don't know if the max economy point can ever go higher than peak torque, but I don't think so.) Reduce load, and it goes back down again. It's not a fixed point, even on cars where it can be at peak torque. While not entirely related, this also explains why it's more efficient to accelerate at peak torque, as hypermilers will tell you. When you accelerate, you load the engine, which pushes your peak economy point up towards peak torque. But once you hit cruising speed, you stop accelerating, remove the load from the engine, and the economy point goes back down.

That's a lean code. My mechanic friend suggested MAF sensor or low fuel pressure. Also something that came to mind, how trustworthy is the gas gauge? I'm guessing you've made sure it has gas already...

Yeah, like biotex said, that chart only shows what rpm you'll be running at 65mph. Useful for doing gear ratios, but not really for figuring out you best mpg.

Not true. There's an efficiency point that moves around depending on load and a few other variables. Usually it's significantly below peak torque. Best mpg I've ever had was cruising at around 1800 rpm. If I go much faster, my fuel economy makes a steep downward curve. onlyinajeep726, where did you get that list and what exactly are the numbers? As in where do they come from / how were they determined?

Just a thought, when the security systems in GM cars (passlock) starts misbehaving, it can sometimes do weird $#!&. Usually it's only temporary. I'm guessing the car can't get running long enough (or at all) to start throwing codes?

Potentially one member had a "bad" link in their sig? Few people got referred to the "wrong" site from the forum, and the forum got hit for spam? Just a guess on my part. All I can say is that y'all have been doing a good job of keeping up with it. Haven't personally seen any spam for almost a week.

New pads and rotors... brakes started grinding. Pads were good, but when I checked the rotors, they were groovy, baby! Looks like the PO ground the pads down past the rivets once and did nothing to the rotor, since the pads had lots over a 1/4" still on them, just had worn to match the rotors. Guess I musta picked up a rock that made it grind, but I'm glad I checked. Braking is a lot less squirrelly now.

I also see that story as sensationalized media with a political agenda. Directed towards the conservative, often the older generation, trying to stir up a reaction. Unfortunately news stories are a commodity, and the media is really only there to make money. Everything is sensationalized so they can sell more of it to make more money. There's a reason newspapers and such are only written to a grade five reading level, and it's not because they want kids reading it. If anything newspapers are worse than tv, because they all are biased politically in some way or another, and people are more inclined to believe what they read in print.

Had a catch-22 like that myself not that long ago... locked my keys in the truck (room and MJ keys) and my spare key was locked in my room. The steel bedroom doors they have in my college dorm would take a cutting torch to get into. And I wasn't about to show the world how to break into my MJ. Fortunately(?) the campus police have keys for the bedrooms...

Yeah, I hear you. I meant you can claim the snow piled on the bumper in front of the plate is there by accident. That way, Officer Popo will just get you to brush it off.

Yeah, I've got some fairly major rust re-repairs planned for the summer (bondo falling out of rockers...) which may or may not result in new paint. The dark blue I've got is kinda starting to grow on me, though... My biggest concern is that I've never really been big on standing out too much. On the other hand, that's not an issue with properly done camouflage, now, is it? ;)

That's what snow's for. You can pretend it was an accident ;)

Heheh, I was replying to istaywikkid. Good to know I solved your problem, though!

Nice! I've thought long and hard about doing a camo paint job, and always somehow manage to talk myself out of it... Well done!

Well I was trying to avoid just throwing that out there...

Carfax gets their info from whoever's willing to sell it. Not all shops keep detailed records, not all shops sell them. Lots of stuff goes unreported. On another note, it's quite likely a good chunk of the damage on it happened when it was stolen. A good portion of auto theft in Canada is kids going joyriding. Jeeps are allegedly easy to steal, and thus are common targets. The XJ was the most stolen vehicle in Manitoba until six or seven years ago when MPI said enough was enough and simply refused to insure/register them unless they had an immobilizer. The number that I remember seeing was something like 1 in 6 of all registered were stolen...

I recently had to press six for english. But it was the first option given. I guess I don't really get much of that issue living where I do. When I was at school in Ontario, though, it did piss me right off. Spanish is one thing cause I kinda speak it, so it was sort of cool listening in on conversations, but all the brown languages... Not too many people who weren't desperate to get away from their country stick around. Mexicans don't really like our winters for some reason...

My dad picked up an old travel van that sat in a garage for ten years, exposed to sun on only one side. Interior was originally pretty close to the second set, but on the bits that saw sun, it's faded to about the same as the first set, and even worse in some spots.

Starter needs rebuilt. I want to say your brushes are bad, but I don't remember exactly which part(s) this "fixes".

5%'s not all that dark. I've seen lots of cars with that walmart stuff on them, and I've never really been impressed. Mostly it's the poor quality install (air bubbles, parts of the window left uncovered, etc) but it's been enough to turn me off the idea. Truth be told, I don't remember ever seeing a properly done install.

Mexico's part of North America...

An MJ is essentially identical to an XJ in front of the doors. You might even be able to find one from the same year with the same engine as yours but runs better. If it's a six cylinder, you can swap that in, too. Anything after 91 uses a different electrical system, which would complicate things, but it's been done. Post 96 goes to OBDII, complicating things more, but again, it's been done. Either way, you should be able to find a write-up on here somewhere.