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OUCH!! Hope this isn't permanent.........

Posted By: SattyNoCar

OUCH!! Hope this isn't permanent......... - 02/22/15 08:29 PM


I've had the Dakota about a month now. I filled the tank up about a week and a half after I bought it.

Topped the tank off again today partly because the needle floats so bad, I wasn't sure how much I had.

First full tank of gas, MPG came back at 9 MPG. Yes, NINE.

Whiskey Tango Foxtrot???

Granted, I haven't given it a full tune up yet, just changed the oil and filters so far, BUT, with that being said, its not belching black smoke, it starts and runs very smoothly, brakes aren't dragging.......

I will admit a majority of my driving is in town, but still, NINE from the V6? I was hoping for around 14.

As soon as I get a clear weekend, I'm going to take a closer look at a few things (like the plugs), but, if this is the best I'm gonna get out of it, I'm gonna have to sell it off. The 440 in my wagon does (did) better.

Kinda bummed and shell shocked right now.......

Posted By: stumpy

Re: OUCH!! Hope this isn't permanent......... - 02/22/15 08:47 PM

You can't really judge the mileage from one tank. You need to get used to driving it and watching how you accelerate etc. To be honest the best I got from my 1998 3.9 6cyl auto was 12mph. That truck is heavier than it looks.
Posted By: moretoys

Re: OUCH!! Hope this isn't permanent......... - 02/22/15 10:16 PM

if you have access to a scan tool you need to read the sensors and see whats going on.oxygen sensors, and air and coolant temp sensors, maybe a thermostat if engine is running cold, cold engine requires more full. NO code will set if it is within operating parameters. The v-6 is not a fuel efficient engine. you are probably only off by 1 or 2 mpg's. I've had my 2000 dakota since new,best I ever saw was 14. Michigan is colder than you are,and I use remote start, I am seeing about 9mpg's right now. driving is about 50 /50 between city and freeway.
Posted By: Grizzly

Re: OUCH!! Hope this isn't permanent......... - 02/22/15 10:36 PM

Start with pulling out your O2 sensor and clean with oven cleaner. Put it back in and try another tank. Usually awful fuel mileage is a plugged air filter or the O2 sensor. Plugged cats is also an issue on these trucks as well, so good chance that's the prob.

During the Magnum era, the V10, 360, 318, and V6 are all within 1mpg of one another.

It was -5F yesterday and I got 14.8mpg out of my 360 Mag in a full-size quadcab, all highway, about 60mph. If it was town it would probably be 12mpg in this kind of cold.

Edit* Shoulda' got that white one.......
Posted By: TrxR

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 12:16 AM

I use to get better mileage out of my 96 1500 4x4 318 auto than my buddies 98 swb 4x4 dakota 3.9 5spd.
Posted By: SattyNoCar

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 12:31 AM

I'm wondering if there is a temp issue. It hasn't been hot out, but, the factory gauge barely moves, and the heat is never really hot (even the hoses to/from the heater are just 'warm') no matter how long its running.

If it is indeed running cold, my short (5 mile) commute to work sure ain't going to get it fully up to temp.

As for the catalytic convertor, when I bought the truck, there were two installed inline, the original one, and back where the stock muffler was supposed to be, another one. The new one was less than two months old, so, when I had a stock muffler installed, I had the shop replace the old stocker with the new one already on the truck (moved it from the back up to the stock location).

I know this thing will never be a Neon in terms of MPG, but, single digits is unacceptable.

Grizzly.....shuddap.
Posted By: stumpy

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 01:05 AM

Replace the thermostat. Cheap and easy to do. Go with the high temp one. I think it's 205-210*. The newer engines like the higher temps.
Posted By: 79powerwagon

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 01:11 AM

I'm getting 18mpg with mine, all country/rural driving, 7 mile each way commute. I think a nice, fresh bottle of sea-foam added to your tank, new tune-up stuff, and a front end alignment will do you wonders! Plus, drive the crap out of too! Mine sat for a long time before I bought it, and I made a point to use up the first tank of gas that first week-end! LOL! It just keeps getting better and better! Even starts reliably at -22°f!

Mine too warms up slowly, but it does warm up. I have a new thermostat for it, I just didn't get it installed soon enough for winter. I'll do it in the spring.
Posted By: 71yelladustr

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 02:08 AM

If its not getting up to proper operating temp it will most certainly use more fuel. The computer will never go into closed loop to reach optimum air/fuel mixture. Put a new 195* thermostat in it and see what happens. FWIW, My 93 3.9 4x4 ex cab auto Dakota got a best of 13 MPG. 12 was common. The funny thing is that I swapped in a 5.9 and got 1 more MPG and a heck of a lot more power.
Posted By: Grizzly

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 02:25 AM

2 cats? Geez, might as well have just stuffed a rag in the pipe to "clean" the air. Good you got that out.

What 71Yella sez: it's running open-loop on you because the ECM thinks it's cold.

Easy fix, but there's a bit of crap to get out of the way to get at the t-stat. A/C doesn't have to be discharged-it will lift out of the way.
Posted By: poorboy

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 06:29 AM

My 3.9 4x4 auto gets a consistent 13-14 around town in the summer, and around 10 in the winter. My old carbed 360 4bbl 80 Dodge 4x4 got 8-9 all the time. I was and am thrilled with 10-14 mpg. Its all in perspective.
On the highway, for the first few miles, it seems like I really have to push the truck to get up to 65, but after a few miles, it loosens up and runs. After a 1/2 hour of highway driving I need to watch my speed, it runs easily at 70+. I'm getting 17 + on the highway. I really never have driven for great gas mileage, I seem to be in a hurry all the time, or maybe its my lead foot..

Don't blame the truck because of a bad thermostat, or short drives, and don't make a judgement call on one tank of fuel. Gene
Posted By: hp383

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 07:05 AM

One of the biggest issues with the magnum engines is the intake plenum gasket.

When that starts to leak, the mileage goes down the toilet.

When I first bought my 92 Dakota with a 5,2 it got 9mpg. I did a tune up, thermostat, and temp sensor change, no better mpg.

Then I learned about the plenum gasket issue, sure enough that was the problem. Fixed that and I was averaging 17mpg with 95% highway driving, with 26" tall tires and 3.55 gears.

I now have 4.30 gears and the same tires, and still get 15mpg.

Attached picture 8438183-92Dakota.jpg
Posted By: Rhinodart

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 07:05 AM

My 92 shortbox 5-speed got great mileage, I bought it new and can remember 18-20 around town and 25 on the highway. 92 was the best year for the V6 though, and I am sure the 5-speed helped. Still wish I never sold that one...
Posted By: mopars4ever

Re: OUCH!! Hope this isn't permanent......... - 02/23/15 06:07 PM

I had a 94 Dakota with V6 and auto trans and it got really crappy mpg`s. If I recall correctly the V8 trucks got the same or slightly better mileage at the time.
Posted By: SattyNoCar

Re: OUCH!! Hope this isn't permanent......... - 02/24/15 03:13 AM


So far it doesn't seem like its using any oil, I may get the plenum repair kit from Hughes just as preventive maintenance.

I'll work with it a bit and see if I can get the number to come up some. Heck, it took three years of fiddling to get my Caravan's MPG back up to what it was supposed to be. The main difference between the two vehicles though was that the Caravan had obvious issues. The hard part was finding the not so obvious issues the obvious ones caused.

I really don't want to kick this truck to the curb, I like the truck too much. I've wanted a Dakota for quite some time, and hope to be able to keep this one for many years.

Thanks for the replies...
Posted By: mopars4ever

Re: OUCH!! Hope this isn't permanent......... - 02/24/15 04:25 PM

If you have mechanical issues you may be able to get better mileage but I bought my truck new and the mileage was poor right out of the gate.
Posted By: HotRodDave

Re: OUCH!! Hope this isn't permanent......... - 02/24/15 08:18 PM

Your t-stat is an obvious issue, either it is old and failing or someone drilled a bleed hole in it. Get a 205 stat for MPG 195 for a compromise and 180 if you want more of the same.

Also seems like you had possible trans issues when you bought it, that can kill the mpg also. Might want to do a full service on it, fluid, filter, adjust bands, tighten line pressure a bit, type F fluid. Can you feel the lock up engage?
Posted By: stumpy

Re: OUCH!! Hope this isn't permanent......... - 02/24/15 08:42 PM

Also try turning the OD off and on while holding steady throttle to see if it is working. If it's working you will feel it shift and the rpm will go up.
Posted By: BIGGERED

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 01:25 AM

I'm pretty sure the od locks out until it comes up to temperature too

This could be part of your issue

Red
Posted By: stumpy

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 01:27 AM

Temp has nothing to do with trans od. Wrong. My bad see my post down a ways.
Posted By: BIGGERED

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 01:36 AM

Stump

Actually it does

When tranny temp is cold od is delayed

Red
Posted By: NITROUSN

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 01:59 AM

Quote:

Temp has nothing to do with trans od.




Are you 100 percent sure on that?
Posted By: volaredon

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 02:40 AM

my 93 with a 318 is better on MPG than my 94 with a 3.9/ but I have never had one 9 MPG-bad. except my 88 D 100,318, 1st year they had TBI.
My 94 (3.9 auto reg cab short bed 3.55s) got a best ever of 18-once- usually 17 on a solid highway run, 14 in the winter in mixed driving, my 318 one (club cab, converted to 5 speed by me, also 3.55s) gets 20 on the highway and 17-18 in mixed driving. never did worse than 15, even towing, with this one. both trucks 2wd,
my 90 (3.9 pre magnum long bed also 2wd, 3.55s) got 16 in town/20 highway, like clockwork.
Posted By: 79powerwagon

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 02:41 AM

Quote:

Temp has nothing to do with trans od.




It sure does when it's WAY below zero! Mine is merely a 3 speed with no lock-up when it's beastly cold out. When it gets to be 10° above zero or higher, it works as it should.

You should hear the rear end SCREAMING in the cold! It sounds like a UFO!
Posted By: stumpy

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 03:08 AM

I stand corrected after some research. I thought the trans temp sensor only caused the trans to drop out of OD when it got too hot. not when it was cold. Isn't that a 1998 and newer thing?
Posted By: SattyNoCar

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 03:47 AM


Yes, the OD is working, and so is the lock up. In certain situations, its noticeable enough that it feels like a 5 spd.

As I mentioned in another thread, I think the previous owner thought the trans was 'bad' because the truck doesn't have the 'snap' of a new vehicle. To me, it feels fine. It shifts as it should. To me, it actually shifts better than the 2002 I used to have. With the '02, I practically had to mat it to get it to drop a gear and pull (like if I slowed way down and wanted to get back up to speed quickly). With this,same scenario, and it drops down a gear without even coming close to matting it, pulls hard up to speed, upshifts, OD kicks in and you're at cruising speed. No fuss, no muss.

Posted By: 85_Ram_4speed

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 03:52 AM

My '96 ext cab v-6 got around 15ish around town, 19-20ish highway. I once--and only once got 22 on a 600 mile round trip after it was given a full tune up. I owned the truck from 54,000 miles to 135,000 miles(9 years). Obviously the older the truck got, the worse it got, but it was pretty consistant to the end.

Sounds as if the T-stat is a little faulty, replace it---factory 195 is adequate IMO.
Posted By: Golden-Arm

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 03:57 AM

my '89 dakota goes into overdrive, as soon as i get up to speed. temp is not a factor.
Posted By: hp383

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 05:46 AM

Quote:

my '89 dakota goes into overdrive, as soon as i get up to speed. temp is not a factor.




My 92 also shifts to OD no matter how cold it is.

The lockup function seems to have a bit of a delay when the trans is cold, but after the engine reaches full temp it works fine.

I am also using a Mopar Performance 166k lockup converter, not sure if that has anything to do with it.
Posted By: WO23Coronet

Re: OUCH!! Hope this isn't permanent......... - 02/25/15 08:55 PM

Any of the Dodge trucks I've owned with an OD trans will not shift into OD when it's cold. I've had a 90,95,96 all do this, even my 05 does it. My brothers 96 and my dads 98 do it as well. And by cold I mean -25C (which is about -13F) and I haven't let it warm up at all (yes I know that's not good for a vehicle but sometimes you have no choice)
Posted By: Blusmbl

Re: OUCH!! Hope this isn't permanent......... - 02/26/15 02:40 AM

On my 05, if it's colder than about 25F outside the converter stays unlocked for the first mile or two of freeway driving.
Posted By: 79powerwagon

Re: OUCH!! Hope this isn't permanent......... - 02/26/15 02:55 AM

It's good to hear that my old is behaving "normal"!

Are these trannys any more complex than a 727 (besides the OD)?
Posted By: hp383

Re: OUCH!! Hope this isn't permanent......... - 02/26/15 03:39 AM

The internals of the transmission no not really. They use the same clutches, and hard parts.

Main difference is in the valvebody with the OD solenoid, and electric lockup (If applicable).
Posted By: SattyNoCar

Re: OUCH!! Hope this isn't permanent......... - 02/26/15 04:19 AM

And by cold I mean -25C (which is about -13F)

If it ever gets that cold around here, the OD or even the truck itself will be the LEAST of my problems.....
Posted By: WO23Coronet

Re: OUCH!! Hope this isn't permanent......... - 02/26/15 06:30 AM

Quote:

On my 05, if it's colder than about 25F outside the converter stays unlocked for the first mile or two of freeway driving.




Sorry I should have added that once it warms up after a couple of miles it will kick into OD
Posted By: GO_Fish

Re: OUCH!! Hope this isn't permanent......... - 03/04/15 04:06 AM

Quote:

Replace the thermostat. Cheap and easy to do. Go with the high temp one. I think it's 205-210*. The newer engines like the higher temps.


I bought a new '90 3.9 Dakota off the dealer lot. First year I drove it, it wouldn't put heat in the cab. Then one day I caught it smoking black at idle. Pulled the thermostat, stuck open. Heat finally worked and truck ran better (normal) after that fix. I want to say it got around 14mpg average, extended cab, 2wd.
Posted By: DaytonaTurbo

Re: OUCH!! Hope this isn't permanent......... - 03/04/15 06:11 PM

Over in the Q&A section, I had a lot of guys disputing me that the V6 does crap for mpg. Less power than the 5.2, same mpg. I think it just takes a certain amount of hp to drive these things down the road. But 9 is bad, worse than it should be. You should at least be seeing teens mpg. Have you checked it fill to fill straight highway driving? Town driving, warm-up, short trips, etc will kill mpg.

FWIW, my buddy and I took his 97 ram 1500 extended cab 5.2 4x4 auto on a 3000 mile round trip. When we were on the flat lands in North Dakota, we ran a tank full of gas at 75mph on the interstate, got 13.5mpg. Slowed down to 55-60 for the next tank and mileage perked up to 18.5mpg. We stayed around that speed the rest of the trip. On the way back home (1500 miles) we were towing my boat/trailer, combined weight about 2200lbs. The poor 318 struggled with the extra weight and drag behind it on the hills coming up through the Missouri, Iowa, Nebraska area. Constantly shifting up/down unless I let it slow down going up the hills or went fast enough to keep it reving higher in 4th. Either way mpg was crap, don't think we broke 14mpg towing. Maybe once we hit the flat lands it had the chance to pick up a little.

My 94 Ford Explorer 4.0L 5sp manual 4x4 would do 17mpg on the highway when towing the same boat. She was real low on power doing it but got the job done. Good thing the highways here are flat and boy did the 5sp ever make towing better. That would have been a miserable tow rig if it would have had the auto trans.

My 99 Ram 2500 5.9 cummins 24v auto 4x4 long box extended cab truck towed the same boat at a consistent 17-19mpg on the highway.

Then later on same buddy bought a minty low mileage 2001 ram 2500 v10 5sp 4x4 extended cab long box. I borrowed it when going to pick up a dart sport I was buying. On the hour drive dragging the tow dolly out there, the overhead console showed a typical 12-13mpg. On the way back with the car on the dolly the mpg remained unchanged and I sure never felt the car on the back.

So basically if you're only getting 9mpg, that's worse than a 3/4 ton v10 truck with 3x the power and towing capacity.
Posted By: SattyNoCar

Re: OUCH!! Hope this isn't permanent......... - 03/06/15 02:38 AM


We had three days of temps in the upper 70's, my gas gauge basically didn't move for three days.

Today, the temps dropped back into the 30's and my gas gauge is just free fallin' towards empty.

Gee, could it be a temp issue?


I got my tax refund, so, I went ahead and ordered the hughes kit (not burning oil, just preventive measures while I have the $$$). I'm also gathering up the rest of the parts for a tune up and to change the T-stat out.

Now I just need a couple of clear days.
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