Can Comanches be reliable daily drivers?

[johnny quest]

yea the coasting will certainly help, especially on the way home since more than half of my drive is coast-able at highway speeds :)

[Pete M]

the engine uses practically nothing to idle. it is not advised that you shut off your engine on downhills or at any time while on a road. you lose your power brakes and steering and in the event of an emergency situation, you will be at a severe disadvantage.

 

the best mileage from the older jeeps comes from maintenance and good sensors and driving like my grandma.

[jeepcoma]

the engine uses practically nothing to idle. it is not advised that you shut off your engine on downhills or at any time while on a road.

 

You don't get much fuel savings with EFI either, only carbs. Most (not actually sure about the HO or Renix programming) EFI engines shut off the fueling when coasting and other certain conditions. Even though the engine is "on" while coasting, no fuel is being used (meaning, you actually use less fuel coasting in gear than by putting it in neutral). A carb on the other hand meters fuel whenever there is airflow, so yes you'd technically be using gas with the throttle closed and going downhill.

[Comanche County]

You can find plenty of upkeep info in the stickies in the Tech and DIY sections. Read those, read the manual linked below and know it. The renix is easy to diagnose with a DMM 90 % of the time, any problem you can't figure out, the good folks here usually can narrow it down for you quickly.

 

I've got two high mileage Renix 4.0Ls (180K + 210K) and wouldn't hesitate to drive either one to Alaska and back.

 

Maintenance links: :wrench:

http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm

http://jeep.zerok.ru/index.php?page=21

[RockMJ]

If your starter is good and on a down hill or something, you can turn off the engine, coast, and then crank back on when you need it.

 

Future Darwin award nominee :roll:

 

RockMJ

[Comanche County]

Not sure if all this talk about a Renix not using fuel while coasting is entirely accurate. When I lived in CO, I had an 8 mile downhill on the way to work at 4:00 in the morning. I coasted with the engine off almost every morning. There was no other traffic on the road, otherwise I would crank the engine on for safety reasons.....also, I never coasted with the engine off if there was ice or snow....only in dry pavement conditions. Yes, the computer will reduce fuel delivery while coasting, but it still provides fuel to allow the engine to idle or else the engine will die, engines don't run if there's no freakin fuel. If your engine is on, it is burning fuel!

 

As far as power brake effectiveness when the engine is off --- your brakes will still work, you just have to apply more pressure, boosters would never have been approved for use on a public highway if they completely depending on engine vacuum. When you coast, just don't be a jerk about it.....adjust your braking and driving style, coast slower, a steep hill will allow you to naturally gain a lot of speed, you don't have to use it all, just keep going fast enough to make it down the hill. Go ONLY slow enough to make it down the hill and no more! Brake as necessary. If you coast down a hill without power until you reach 70-80 mph then wonder why you can't stop quickly then there needs to be a mental examination. Sure coast as much as you can, don't do it in traffic, don't do it in wet/slippery conditions, increase your stopping distance by a very wide margin, ensure there's an open road, if there's any doubt, start your engine, drive normally and don't risk safety. Don't do it with other cars around you.

 

Yes, you can coast and save fuel with the engine off. That is a fact,,,just don't be a retard when you do it. Coasting for short distances won't help, it uses a lot of fuel just to start it up. I'm talking about a several mile down hill distance. If you've got a very long downhill, like coming off the freaking great divide like I was every morning, then you will save gas - FACT! I was getting well over 25 MPGs going to work in the wee hours of the morning with a lifted MJ on 33s, coming home going over 3,000 feet uphill was a different matter.

[CGross]

If your starter is good and on a down hill or something, you can turn off the engine, coast, and then crank back on when you need it.

 

Future Darwin award nominee :roll:

 

RockMJ

 

There's a difference between "No one on the road at 3:30am so I can coast it" and "It's 5:00pm on Friday in the middle of the interstate". It's 95% common sense when doing those kinds of things.

 

The only power thing I have in my MJ is the brakes. And I think somethings up with that even since it's not actually the best in the world. :hmm: So I don't notice a difference too bad.

[glundblad]

I have an '87 and although it is no longer my daily driver, I wouldnt hesitate to treat it as such. It has the same behavior and characteristics as it did when I bought it new. Mechanically, I don't think it has aged a day. It is a renix and takes 7 cranks to start it. The same as when new.

 

I would hesitate a bit in winter due to the salt on Indiana roads however.

['87 fuel-miser]

1 week a month , i give my '99 xj a break and drive my '87 mj ( 2.5 / 135000 miles 4 -sp ) back and forth to work , a total of 80 miles round trip ( x 5 )... NO PROBLEM ! it's much better on gas and it's a smoother ride ! THE VERDICT : yes , they can be reliable ! as long as you don't drive like Steve McQueen and do regular maintenance :banana:

[johnny quest]

what kind of terrain are you driving (hills vs. flats vs. city) and what kind of mileage are you getting??

[big66440]

I'm planning on driving everywhere with this baby, from the lows of death valley to the highest peak in the states, ice cold morning starts to 3 digit hill climbs in mid summer, I'm aware of the possibility of "surprise" problems with anything automotive ( I fix cars for a living) but the whole purpose if possible is to "pinpoint" the weaknesses of these awesome rigs :brows: to try and prevent them, I'm a mopar guy through and through and know they can build bullet proof vehicles and this is the one I personally think is unique and worthwhile,,,just out of curiosity how much of this 89 4.0/AW4 D35 SWB manche is mopar I know the trannys Aisin Warner (japanese/german) built but what about the rest?

[bentnotbusted]

just out of curiosity how much of this 89 4.0/AW4 D35 SWB manche is mopar I know the trannys Aisin Warner (japanese/german) built but what about the rest?

zip, zilch, nada.

 

Somebody may enlighten me as to some small tidbit that I've forgotten but I don't think an '89 has any mopar in it at all (pentastar on the key maybe, lol). By the '90 model year a few bits and pieces (brake calipers for one) started to sneak in, with the chrysler electronics coming in '91. Kind of ironic really given how many other manufacturers are in there. Chev steering column, alternator, and some other stuff here and there. Ford distributor and retractable underhood light (if equipped). The previously mentioned Aisin transmission, which I too will vouch for, I'm a die-hard mopar guy as well and I actually swapped out a t-flite for one in my truck. And, of course, the Renault/Bendix fuel injection system. It's an odd mismatch of pieces really, but it's all dead reliable with a little basic maintenance. I DD my car in the summer for the fuel mileage but our winter DD's are an '87 XJ with 320K kilometers (200K miles) and my MJ with unknown mileage well in excess of 500k Km. Both fire up on the first turn of the key, regardless of how cold it gets.

[big66440]

Oh, guess i got a little too excited with the pentastar logo on the emissions sticker :hmm: