I Increased My XJ Gas Mileage To Over 20 MPG

[RichP]

The only downside is I keep getting flipped off, by chicks talking on their cell phone with their window down as I accelerate past them.

Damn that happend to me yesterday when I had blackfoot tunes playing in the TJ topless thru the new pioneer speakers, so I turned it up when train came on..then the light changed and I was gone..

 

[MudDawg]

Schweeeettt Rich....All hail the gone but not forgotten Shorty Medlock.

 

[boycelaforest]

Just read this post, tune up = better gas mileage, who wold have known?

 

[PapaPump]

btw about the sub-topic introduced in this topic about running without a muffler: don't believe the lies, it will sound like ass...seriously ASS. yeah it sets off car alarms...but you will hate it after a short road trip. if you thought the bumble bee sounds the ricers make were shitty, just wait until you hear an unmuffled jeep.

 

[ATMA weapon-XJ57]

Well it's been a process of trying to get some more HP out of it as well as increasing MPG. My original jump came 2 yrs ago when I bought a high flow tube and air filter off of ebay (it was about $50) and a 160 degree therostat. I picked up some power and went from 15 to 17mpg (of course I did the normal things like the intake cleaner in the gas tank and synthetic oil in the crankcase.

But my big jump came about 2 months ago when I decided to give it a good tune up. I started out by replacing all of my major hot and ground wires under the hood (Wal-Marts 2 guage battery wire is almost 600 strands of twisted wire and cheap, just cut them to size). This didn't make a noticable change in MPG but my windows started going up faster and my headlights were brighter. This has to mean more voltage to the coil. I then started to replace plugs, wires, and cap and rotor. I decided the more electricity the better the burn in the cylinder. I bought Excel 300+ wires that have only 150 ohms of resistance per foot (these list for over $100 but I bought a brand new set off of ebay for only $50). I also used platinum plugs which I thought were just as good as the Iridiums. And then I finished it up with the best cap and rotor autozone has (I compared it to Excel and all the important features are there which most importantly brass posts). All total about $100.

I've also realized that my xj with 135,000 miles likes a mid grade 89 octane gas over regular 87 octane (I still come out ahead with the increased mpg). And I've saved about $35 in fuel cost over the last 2 months. 4 more months my upgrades are paid for and then it's all savings!

Oh and by the way, the increased HP gets my boat (3000lbs) and jeep up to 60 mph by the time I'm getting on the highway (on the average grade ramp). This is a bonus that makes the price of the upgrades well worth it.

did you test out your MPG rating before and after the tuneup? and how did you test? with changing the wires, are you draining more battery or alternator power? i assume the wires used were a different guage correct?

 

[TiRod]

of course I did the normal things like the intake cleaner in the gas tank and synthetic oil in the crankcase.

Good for changing the cables - after 15-20 years the factory ones are guaranteed to have lost volts to corrosion resistance.

But what other things did you do besides the synthetic oil?

 

[Loose_Nuts_Enterprises]

and smoke the 35" mt's ( front and rear ) on dry pavement and i only run 87 octain, can you imagin that?:confused1

You have no idea how bad I want to watch you do that, Troy! :explosion

I need to change my flux capacitor, and a new stick of plutonium, so I can get 400mpg:laugh:

-Dan

 

[Mr.OverKill]

You have no idea how bad I want to watch you do that, Troy! :explosion

I need to change my flux capacitor, and a new stick of plutonium, so I can get 400mpg:laugh:

-Dan

i said can you imagine that, i can! ( imagine it i mean )


P.S. PM sent

 

[xjgrn]

When my Xj was brand new in '96 it too got that low to mid 20's on the hiway. Ever since I began lifting it, bigger tires, and such, it has settled on 15-16 mpg's. tune ups always help a bit, but eventually the numbers fall off.

 

[krakhedd]

I dunno if anybody said this yet, but.....THIS THREAD IS POINTLESS! Basic stuff to increase mileage, that's all........probably would have had the same effect replacing stock ignition components, save maybe for the coil, with the wiring upgrades......better grounds/etc. = more spark which, generally, results in more complete combustion....

I dunno how higher octane results in better mileage, except if knocking/pre-det was a problem in the first place.....higher octane = lower BTUs/unit volume.....only better mileage for a motor tuned for higher compression, which may work if you've got a cam and/or have tweaked the ECU....

As for me, I'll continue to blame my lead foot for my horrible mileage - I can get 18MPG or better reliably on the highway, but generally during these summer months have been seeing between 16 and 17. I'm sure that replacing the trash stock grounds/etc. would help considerably in this department as well, as may restoring a small amount of backpressure to my exhaust - though I'm still about 45% or less that this would help....

For the record, I've got a Poweraid TB spacer, home-made K&N w/IAT relocate, Borla cat-back, Bosch Platinum +4s, hollowed stock cat, and since it's an '01, I have the coil-on-plug ignition. Everything listed except the cat were on my nearly-identically-equipped 99, good for 18.6MPG (maybe 18.7) on a 250-mile trip, averaging 83MPH (God bless Canada/Southern Ontario - wide open expanses, easy to catch speed traps).

I also am far more inclined to blame the gas in the area. We have some of the highest prices, and being that politicians in New York just LOVE to "improve" everything through legislation.........

EDIT: oh, and almost-stock-size GY Wrangler Silent Armors....245/75s if I recall correctly......no lift....

 

[ncjeepfreak]

hey that deffinately can't hurt, new parts do usually help. maybe you could send me a full list of the parts you orderd. it would be much appreciated. i currently get 18 mpg out of my 99 xj, but it has 180k on it so i don't think putting a few new parts on it would hurt.

 

[Ecomike]

I was somewhat shocked to read over half the negative posts in this thread, but although the idea of replacing the main Renix ground wires with heavier gauge wires and fresh connections, and replacing the wiring harness hot wires from the ECU to the ignition modual (which Is what it sounds like he did) while not entirely new, is new to me with respect to the huge effect it could have on stock ignition performance and specifically the final MPG results.

While I and 5-90, et.al., have preached about fixing ground problems to solve all sorts of idle, ignition....gremlins and problems with the Renix XJ's, it never occured to me that I might be missing say 20 to 30% of my peak electron flow to the spark plugs because of a slightly overloaded ground system when all my power items are turned on, like head lights, electric radiator fans, A/C blower...etc.

I may just have to recheck my other grounds and look at upgrading my cleaned OEM stock ground wires, with larger wires, larger surface contacts on the connectors, and look at the +5 volt signal wire and ground wire to the ignition coil itself. I have already solved some Renix problems with things as simple a new direct TPS ground wire to the battery to eliminate a 13 ohm ground problem on my TPS caused by the wiring harness.

Frankly, I am impressed his results!

 

[rocknxj]

I, for one, am glad he's out of the 15 MPG club. It was getting too crowded in here anyway.

 

[tkjeeper]

I, for one, am glad he's out of the 15 MPG club. It was getting too crowded in here anyway.

HA! Too funny! But too true!

 

[88manche]

I get 12 - 15 mpg, and a 4 cyl!!!:scared::scared:

 

[cdn_xj]

Wow...I have to confess that I, too, am shocked at the number of posts that are mocking/belittling the OP. He discovered something that, obviously, was news to him and he decided to share it with the rest of us. I admit the coy-ness of the original post was probably unnecessary, but the degree of contmpt displayed in the negative reaction is pretty poor form.

 

[RyanM]

2 years ago.....!

 

[cdn_xj]

2 years ago.....!

LMAO

Didn't even notice.

Blame Ecomike for digging this one out of the archives lol

 

[joshv98xj]

Wow...I have to confess that I, too, am shocked at the number of posts that are mocking/belittling the OP. He discovered something that, obviously, was news to him and he decided to share it with the rest of us. I admit the coy-ness of the original post was probably unnecessary, but the degree of contmpt displayed in the negative reaction is pretty poor form.

Yeah, apparently he didn't receive it too well. It looks like the only 6 posts he ever had were in that thread. What's even more, his last post was 6-16-06, so he didn't even read the end of the only thread he started! You guys are bad.:twak:

 

[scottmcneal]

Heres a post i found one day... Makes you think, what else do people talk about?

I asked if they'd been on ::...they had 3 XJs in the party so I figured a resounding yes was due. They grunted and groaned and said they'd had enough of the cocky, know-it-all, badmouthing types that coomprises 80% of ::. I voted they tried a round two with some of the local guys in the NWC, we'll see..

Like i said, i FOUND this running around an reading...Why would you want to join, when all you get is chit?????? I try to nice to everybody but some of these guys can be RUDE...