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-   -   Very high Fuel consumption on 4.0L TJ (http://www.wranglerforum.com/f282/very-high-fuel-consumption-on-4-0l-tj-129431.html)

JAYH.TJ 12-25-2011 03:42 PM

Very high Fuel consumption on 4.0L TJ
 
Hello this is my first post on this wrangler forum.



Recently fitted a new mopar oem fuel pump on my tj due hard starting problem and it has cured the problem . but its gone really bad on fuel consumption ive got the 19 gallon tank fitted and im only getting 200 miles out of it until the reserve light comes on. what could it be?

jeep has stock supspension with no lift, 29" bf goodrich allterrain tyres and also has a k&n air intake kit . the jeep has been stored for the last 5 years and only has 23,000 miles on it .

JBD 12-25-2011 03:58 PM

Did you get all of the old fuel out? When you put the new pump in did you change the level at which the light comes on? There may be more fuel in the tank then you think. Try a tuneup, plugs wires, cap, air filter etc.

XJ Knight 12-25-2011 04:07 PM

To add to the above That K&N isn't helping you out either

JAYH.TJ 12-25-2011 04:27 PM

when i got it out of storage i had changed the oil+filter ,fuel filter, plugs and put the k&n kit on it , i also changed the throttle position sensor due to not idling properly i had been using it for about six months so it had fresh fuel in it. when i replaced the fuel pump i replaced it with a new complete unit because when it got to a quarter left it was on empty and now the needle goes all the way to empty .
i was thinking about replacing the HT leads .

Thanks for the reply

AntiTrust 12-25-2011 04:56 PM

have you checked your injectors? just a thought because if they sit for a really long time it has been known to cause defects.

JAYH.TJ 12-25-2011 05:21 PM

I think the injectors are ok because the jeep runs great lots of power and there is no faults codes or no rough running,

JDsDream 12-25-2011 05:36 PM

Welcome to the Forum

There are several factors that can effect mileage including the octane rating or the ethynol content of the fuel itself. I have an 06, 4.0 I6 and 200 to 230 is about all that I get out of mine.

AntiTrust 12-25-2011 05:45 PM

almost smell the exh and make sure its not running rich, IE no high fuel smell :)

Joshpeb2 12-25-2011 06:45 PM

Quote:

Originally Posted by JDsDream (Post 1857947)
Welcome to the Forum

There are several factors that can effect mileage including the octane rating or the ethynol content of the fuel itself. I have an 06, 4.0 I6 and 200 to 230 is about all that I get out of mine.

Mine is an 05 but, thats about all I get outta mine too. If I push for 235 I'd be walking. Mine could use some new plugs though.

rrich 12-25-2011 07:00 PM

Check for an exhaust leak ahead of the O2 sensor.
The exhaust pulses, pressure to vacuum. A leak lets Oxygen get to the O2 sensor, causing it to run rich.

Dribble a little oil down the throttle body to make it smoke a little, stuff a rag in the tailpipe to pressurize the exhaust, then go underneath with a strong light to see where smoke's coming out.

sknybkr44 12-25-2011 07:03 PM

I get about the same with mine

Mr_RPM 12-25-2011 07:04 PM

when you fill back up does it take close to 19 gallons?

my light sometimes turns on at 200 miles but I usually still have 4-5 gallons left. the fuel gauge lies and says its empty waaaay before it is.

ejxjohnson 12-25-2011 07:15 PM

Quote:

Originally Posted by Mr_RPM (Post 1858082)
when you fill back up does it take close to 19 gallons?

my light sometimes turns on at 200 miles but I usually still have 4-5 gallons left. the fuel gauge lies and says its empty waaaay before it is.

what he said! when my light comes on i usally ave around 200 and i drive around for another day or so and get gas and most of the time im only putting 16 or 17 gallons in for a full tank.

1jeeplvr 12-25-2011 07:21 PM

I think you should figure what your actually getting for fuel mileage.My XJ only gets 15-16 mpg.

AntiTrust 12-25-2011 08:35 PM

16.5 for my JK :)

zdragon 12-25-2011 09:30 PM

Quote:

Originally Posted by AntiTrust (Post 1858264)
16.5 for my JK :)


that's above average gas mileage for a Jeep.

sevenservices 12-25-2011 09:35 PM

^yeah. Also make sure you don't have a low tire somewhere... causes a lot of extra drag. Same w/brakes if they are dragging in the back or something.

Rubicondon53 12-25-2011 10:03 PM

200 miles is about right,,, that's what mine does with 4:11s and 33s. It seems early, but it's happening around 1/4 tank, as I usually put 14 or 15 gallons in at that point..

Remus_Redbone 12-25-2011 10:07 PM

Figure you actual mileage. If the float / sensor it out of whack and the low fuel light is coming on when you have 4 or 5 gallons left in the tank as mentioned by a couple replies, you are getting 13 to 14 mpg and sadly that's not all that far off for 4.0L Jeep.

Black98 12-25-2011 10:11 PM

Gotta calculate MPG using the good old trip/amount required to refill back to full. Using the fuel guage in anyway on these Tjs will mislead and worry you. I always calculate MPG on every tank because dips in MPG often can help show a problem before any idiot code ever appears.

XJ Knight 12-26-2011 12:16 AM

Is it winter in England? Winter grade gas perhaps could be a contributing factor if they use that in england. It will hurt your mpg a bit.

WaterDR 12-26-2011 03:48 AM

Not unless there is ethanol in it. And if there is, it will still be mostly gasoline.

Rubicondon53 12-26-2011 09:08 AM

Quote:

Originally Posted by Black98
Gotta calculate MPG using the good old trip/amount required to refill back to full. Using the fuel guage in anyway on these Tjs will mislead and worry you. I always calculate MPG on every tank because dips in MPG often can help show a problem before any idiot code ever appears.

Agreed 100%. My kids think I'm anal about MPGs, my Rubi " averages " 15 mpg, with medium grade gas. If it dips, I know something needs fixing, way before idiot lights will warn me, and way before it just quits running.. I learned to clean the throttle body, the idle control, and all the sensors because of dips in MPGs.

Shelby427 12-26-2011 09:10 AM

And don't forget the one thing you can control, your right foot.

How you drive will greatly affect your mileage.
When my wife drives she's lucky to get 200 miles on a tank. Me? I've gotten over 300.

navyspence92 12-26-2011 11:43 PM

It's a jeep. If you're worried about gas mileage you've got the wrong vehicle lol

JeepWrangler4x4 12-27-2011 12:07 AM

sounds about right too, all depends on how you drive basicly.. but i average about 200 with 19 gal tank before the light comes and then i run it 2 more days and only end up putting in like 16.5 gallons, but i got a program on my phone called aCar and it does all my MPG for me, most ive ever gotten out of a tank was 17 something during the summer, and when my thermostat was stuck open it dropped it to 12.5 to 13mph, with it being winter and such it get about 14-14.5mpg all depends on if im doing city or highway driving and if im doing 60-65 on the hwy or 75-80 on highway

I also run 87 rating with no ethanol, i also run lucas fuel injector cleaner and such if i have some in my jeep at the time

00tj2 12-27-2011 09:39 AM

Where do you get gas without ethanol???i wish I could get some of the "old gas" here in lower ny. I lost about 5 mpg average ( went from 18c-24h to around 17mpg everywhere) when they changed the fuel.

JeepWrangler4x4 12-28-2011 07:17 AM

we have a couple gas stations that offer no ethanol around here, one of them is a R-store and they just started it a few months ago and the other is fleet farm which is a all purpose store with a gas station but not sure if they still do haven't got gas from there in a while since its a 25 min drive. But my last MPG was 15.169mpg with about 75% highway driving on that tank from the holidays.

WaterDR 12-28-2011 09:23 AM

You have to just ask around. If you stop at a marina you will find someone that knows likely. People with 2 stroke boat motors can't use it. While around here I would say that 90 percent has ethanol in it, many stations have pumps that are marked no ethanol near where people boat.

thetoadLJ 12-28-2011 09:47 AM

fwiw im running 32s on 3.73s and get about 200 avg per tank depending on city/highway driving and my light comes on i have about 3 gallons left im guessing. i always fill about 16 gallons into my jeep when i hit the pump.


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