fuel mileage question

Joe Romas · **Posted:** Tue Nov 04, 2008 11:27 am

CounterCulture wrote:

I Forgot one thing. When is it necessary to prime the fuel pump? I've never actually done it, is this bad?

When you have symptoms that may point to lack of proper fuel flow. I know, not a good answere

Try pushing the plunger and see if it's firm. If so fine. If not then bleed the air out and see if it changes anything.
Mine had a air problem and a intank pump resolved it. Besides the "studdering" or "bucking" it seemed to resolved what many think, and I don't, is the so called turbo lag from a stop. At it's worst mine would pause two seconds before responding at all and it varied and you never knew when :shock:

.
Pull the MAP and see how cruded up it is. I clean mine on very oil change. First time is a bear because you need to remove the two clips holding the wire loom then you'll find the allen head screw way too tight. Get some 6mm nuts to hold the wire loom instead of the clips :wink:

DarbyWalters · **Posted:** Tue Nov 04, 2008 11:42 am

NEW EPA ratings for the CRDs is 19 city/21 mixed/23 hwy.

If you have a lift/armor/heavier tires/ect., you should be happy to be getting these numbers.

I am getting an average (tracked religiously over the past year) of 20.5 with basically 85% city Stop n Go. I do have an OME lift and 235/75/16 tires. My odomoeter reading with the taller tires is 5.7% less than actual miles traveled (GPS and MIle Marker verified). So most here with taller tires can add 6% to their hand calculated MPG numbers. I can get 28 MPG on strictly Hwy at 65 MPG (GPS).

Hjalti · **Posted:** Tue Nov 04, 2008 5:50 pm

At the moment I'm getting 14.2 mpg (16,7 l/100 km) mostly urban around 40 °F (5 °C). Last time I filled up it was around 13 mpg (18 l/100 km) it was a bit colder then and also urban, there is good correspondence between the computer and hand calculated. I have a new MAP sensor and everything seems to be in good working order. I think the exhaust smell is a little different from many European common rails I know, hard to describe. Also worth noting is black smoke when flooring it but that is something that appears to be common on the CRDs. But isn't black smoke an indication that it is getting too rich fuel mix?

KJ79 · **Posted:** Tue Nov 04, 2008 6:03 pm

(Happy Election day!)

Y'all should be pleased with your fuel consumption.
My NEPA (Non-EPA) rating is 14 mpg in the mixed driving cycle, that is no stop-and-go but 50% suburban 'round town and 50% highway driving, strictly highway is marginally better at about 15 mpg.
Movement of fuel gauge from a total fill up - needle well past F mark down to the F mark is about 40 miles. From F to 3/4 about 50 miles, 3/4 to 1/2 about 50 miles as well. Down to 1/8 mark 239 miles and 17 U.S.gallons to fill'r up last week. Yup 14 mpg.

Do I now qualify for worst CRD mileage ever? Any other winners out there?

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

Have you guys done the usual maintenance checks for MPG? Clean air filter, clean MAP sensor, ORM mod, fuel filter in good shape? Black some in a CRD that isn't running a tuner of some kind sounds to me like something is gummed up.

geordi · **Posted:** Tue Nov 04, 2008 7:49 pm

Wow, that really sucks for you. My VW Jetta TDI managed a glorious 10mpg for about an 800 mile trip, but there was a good reason: One of the high pressure fuel lines had burst and I was driving on only 3 cylinders. That #2 cylinder was happily getting it's fuel sprayed onto the front of the engine while I drove. Not the best of situations.

Are you sure you don't have a seriously stuck injector? BTW: My CRD now doesn't smoke at all, unless I have the Edge TrailJammer in high-power mode and I FLOOR it from a dead stop. Otherwise... It's just powerful like crazy.

geordi · **Posted:** Wed Nov 05, 2008 3:13 am

Turbo lag on the autos is felt only from a dead stop or slow roll in first gear. Once you are moving, so is the turbo, and its easy to rip it up to 30,000 rpm with a push of the go button.

The lag on the autos has two causes that I have been able to determine: Turbo and bad torque converter design.

What the lag feels like is you stomp on the pedal and the car starts to move slowly for about a half-second to a full second while the engine roar increases... Then just about the same time the engine reaches that magic 2000 rpm and the converter FINALLY starts to put some power to the tires, the turbo boost kicks in, and you get an arse full of seat.

If the converter was designed with a MUCH lower stall, say around 12-1400 or so, the power would come on faster b/c the engine can't make boost unless it is burning the fuel. Try revving it up at idle and see what your boost gauge says. You will be lucky to find 5 psi. When the engine is loaded, then it burns fuel to make the hot gasses for the turbo's fuel... And you get go-power.

mackruss · **Posted:** Wed Nov 05, 2008 3:43 am

Joe Romas wrote:

CounterCulture wrote:

I Forgot one thing. When is it necessary to prime the fuel pump? I've never actually done it, is this bad?

When you have symptoms that may point to lack of proper fuel flow. I know, not a good answere

Try pushing the plunger and see if it's firm. If so fine. If not then bleed the air out and see if it changes anything.
Mine had a air problem and a intank pump resolved it. Besides the "studdering" or "bucking" it seemed to resolved what many think, and I don't, is the so called turbo lag from a stop. At it's worst mine would pause two seconds before responding at all and it varied and you never knew when :shock:

.
Pull the MAP and see how cruded up it is. I clean mine on very oil change. First time is a bear because you need to remove the two clips holding the wire loom then you'll find the allen head screw way too tight. Get some 6mm nuts to hold the wire loom instead of the clips :wink:

That's an interesting point you make.

With my manual CRD, i've always felt a slight lag when engaging second gear but not the other gears funnily enough. I've only owned two diesels before, my first one was a Mitsubishi TDI and now the CRD and prior to that about 12 gassers ( PATOOIE ) and that is why i thought the in line Facet pump that i fitted would be the answer to my problem which turned out not to be the case.

I don't know if i'm experiencing turbo lag or fuel starvation but what i do know is that there was a noticeable difference when i free flowed the exhaust system but that irritating lag in second gear was still there.

The auto boxes may be different, i don't know as i have never driven a CRD auto but i would be interested to read more about turbo lag and the symptoms associated to it.

WolverineFW · **Posted:** Wed Nov 05, 2008 4:00 am

KJ79 wrote:

(Happy Election day!)

Y'all should be pleased with your fuel consumption.
My NEPA (Non-EPA) rating is 14 mpg in the mixed driving cycle, that is no stop-and-go but 50% suburban 'round town and 50% highway driving, strictly highway is marginally better at about 15 mpg.
Movement of fuel gauge from a total fill up - needle well past F mark down to the F mark is about 40 miles. From F to 3/4 about 50 miles, 3/4 to 1/2 about 50 miles as well. Down to 1/8 mark 239 miles and 17 U.S.gallons to fill'r up last week. Yup 14 mpg.

Do I now qualify for worst CRD mileage ever? Any other winners out there?

Gotta be something not right. I get about 19-20 mpg driving about 90% stop and go in the city. The highway is another story though......I have hit 30+ mpg on trips to Kelowna on the Coquihalla. I think I hit 34 mpg once coming back from Prince George into Vancouver.

Joe Romas · **Posted:** Wed Nov 05, 2008 7:19 am

WolverineFW wrote:

Gotta be something not right. I get about 19-20 mpg driving about 90% stop and go in the city. The highway is another story though......I have hit 30+ mpg on trips to Kelowna on the Coquihalla. I think I hit 34 mpg once coming back from Prince George into Vancouver.

Are you using "US Gallons" in your figures or "Imperial gallons"? One Canadian gallon is 1.201 US gallons :lol:

See here for conversion calculator.
http://www.clipmarks.com/clipmark/7DEE3 ... 69E19CFD6/

DarbyWalters · **Posted:** Wed Nov 05, 2008 11:28 am

Hjalti wrote:

At the moment I'm getting 14.2 mpg (16,7 l/100 km) mostly urban around 40 °F (5 °C). Last time I filled up it was around 13 mpg (18 l/100 km) it was a bit colder then and also urban, there is good correspondence between the computer and hand calculated. I have a new MAP sensor and everything seems to be in good working order. I think the exhaust smell is a little different from many European common rails I know, hard to describe. Also worth noting is black smoke when flooring it but that is something that appears to be common on the CRDs. But isn't black smoke an indication that it is getting too rich fuel mix?

Where in Iceland are you?...I am from Reflavik. Are you talking US gallons? Thick black smoke is not normal...

WolverineFW · **Posted:** Wed Nov 05, 2008 3:25 pm

Joe Romas wrote:

WolverineFW wrote:

Gotta be something not right. I get about 19-20 mpg driving about 90% stop and go in the city. The highway is another story though......I have hit 30+ mpg on trips to Kelowna on the Coquihalla. I think I hit 34 mpg once coming back from Prince George into Vancouver.

Are you using "US Gallons" in your figures or "Imperial gallons"? One Canadian gallon is 1.201 US gallons :lol:

See here for conversion calculator.
http://www.clipmarks.com/clipmark/7DEE3 ... 69E19CFD6/

US Gallons.....hand calculation and off the EVIC which displays US gallons. Looks even nicer in Imperial Gallons.

KJ79 · **Posted:** Thu Nov 06, 2008 3:29 am

In response to the questions above: As the Imperial gallons in Canada have gone the way of the dodo bird, I am stricly using US Gallons (3.81litres) - this makes it much easier to compare with 95% of the "other" CRD owners in North America.

WolverineFW · **Posted:** Thu Nov 06, 2008 4:43 am

KJ79 wrote:

In response to the questions above: As the Imperial gallons in Canada have gone the way of the dodo bird, I am stricly using US Gallons (3.81litres) - this makes it much easier to compare with 95% of the "other" CRD owners in North America.

Except for car dealers......who like to use imperial gallon mileage figures in their advertising for looks..

geordi · **Posted:** Thu Nov 06, 2008 2:44 pm

They might be doing that in America too soon, just to try and sell more cars.

mackruss · **Posted:** Thu Nov 06, 2008 3:20 pm

geordi wrote:

They might be doing that in America too soon, just to try and sell more cars.

Give your new Pres a chance, shame on you....

geordi · **Posted:** Fri Nov 07, 2008 12:10 am

Not at all a dig at Obama. I voted for him, bc I NEED change in my gov't. Getting 4 more years of the same bad policies... No thanks.

No, I actually trust car dealers LESS than I trust any politician. Every once in a while, a politician will actually do something that will HELP the customer (the public) while a car salesman will NEVER do that.

widowmaker · **Posted:** Fri Nov 07, 2008 3:09 pm

mackruss wrote:

Give your new Pres a chance, shame on you....

Seeing that you are from South Africa, that comment hit me wrong. Maybe I'm still a little sore about the election, so I won't hold it against you...but I found this on wikipedia:

Since the ANC-led government took power, the United Nations Human Development Index of South Africa has fallen, while it was steadily rising until the mid-1990s.[15] Some of this could possibly be attributed to the AIDS pandemic and the failure of the government to take steps to address it,[16]some of it can also be pinpointed to a government policy of redistribution of wealth

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

Not sure what any of this has to do with fuel economy.

Also not sure I'd go with South Africa as a test case to back up the whole "he'll redistribute the wealth" fear mongering. That always struck me as having a pretty clear subtext of taking wealth from successful white folk and giving it to lazy minorities. Its the same philosophy that was used to justify Apartheid in the 70's and 80's, which prevented 80% of the country's population from having a say in how the nation was run.

Better example might be the King of England back in 1776 noting how those whacky colonists wanted to redistribute the wealth, taking it away from the Crown and British trading companies and giving it instead to low-born commoners.

The sooner Americans start behaving like Americans, and not allowing ourselves to be manipulated by political hacks, the better off we are going to be. We've got big problems, and slogans and sound bites ain't gonna fix em.

KJ79 · **Posted:** Sun Nov 09, 2008 2:29 am

My mileage has now improved from 16 to 16.4 mpg ! At least this is better, rather than worse, mind you this for 20% city and 80% highway. So in reality it might be worse cause usually I check for a 50/50 driving mix.
Since there is No CEL, no codes everything is fine. FINE?!*
Could it be that the ECM is 'neutered', such that half or more of the fault codes are not stored or transmitted? Hence the dealer is not compelled to do anything, as Chrysler will not authorize any work unless a code shows up?

fuel mileage question

Who is online