Really BAD fuel mileage :-( Advise PLEASE!!!

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

I hope I am posting in the correct place. If not, moderator, please move this to the correct heading.

I have a 2005 CRD. It was getting GREAT mileage numbers (23-30+) until this last spring when the check engine light kept coming on and I took it into the dealer to see why the light was coming on. They put it on the computer and it said the EGR and the PGM (?) was bad and needed to be replaced.

They replaced these things and my mileage went to crap (15-17 at best)

I took it back to them and they did something that brought it back up, but only temporarily. Within a week or so, the mileage was back down in the basement again.

Then the check engine light started coming on again. I took it back and they said the EGR was bad AGAIN. They replaced it, but the mileage continues to be crap.

I met one of the members on here one day while I was out in town. He said to do the ORM and that should fix the mileage problem. I did this but, the mileage still has not improved.

I need to get this problem fixed asap. It's costing me a ton of money in fuel. It seems from reading on here that most Jeep dealers don't know as much as they should about the CRD. I need to take it back to a dealer and get them to fix this but I don't even know where to start asking them what might be causing the problem.

Somebody please give me some advise about what is causing this and what needs to be done to get it fixed!

bugnout · **Posted:** Fri Oct 05, 2007 12:31 am

Clean the MAP sensor. (this is not even in the service schedule, but most have found that without the ORM mod, it becomes horribly fouled.)

Do the ORM mod. (unplug the MAF sensor at the air box)

Try that and see if it makes a difference.

Sir Sam · **Posted:** Fri Oct 05, 2007 12:48 am

also check the airfilter(duh)!

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

bugnout wrote:

Clean the MAP sensor. (this is not even in the service schedule, but most have found that without the ORM mod, it becomes horribly fouled.)

Do the ORM mod. (unplug the MAF sensor at the air box)

Try that and see if it makes a difference.

What should I clean it with?

The MAP sensor that is what I unpluged when I did the ORM. correct?

The airfilter is new.

I know it seems I'm a little "blond" here, but I really don't know much about these engines.

Sir Sam · **Posted:** Fri Oct 05, 2007 12:52 am

jwalker wrote:

bugnout wrote:

Clean the MAP sensor. (this is not even in the service schedule, but most have found that without the ORM mod, it becomes horribly fouled.)

Do the ORM mod. (unplug the MAF sensor at the air box)

Try that and see if it makes a difference.

What should I clean it with?

The MAP sensor is that I unpluged when I did the ORM. correct?

No, you unplugged the MAF sensor, but that disables the EGR. The map sensor is up on the intake plenum, its becomes clogged with soot pretty quick. Clean it with some electric parts cleaner or MAF cleaner, both can be had at a local auto parts store.

bugnout · **Posted:** Fri Oct 05, 2007 12:54 am

You remove the MAF (Mass Air Flow) sensor for the ORM mod.

The MAP (Manifold Air Pressure) sensor is on the top of the engine near the firewall. Its job is to sense the amount of turbo boost your getting and adjust fuel pressure as required.

Its is attached with a single hex bolt, but can be hard to get to because of the wiring harness that sits on top of the engine.

See this thread http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=22630

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

thanks a bunch guys.

I'll give it a try

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

One other thing I was curious about...

Why would the mileage just suddenly go from excellent to really bad?

One day it was fine, then the next it was awful. The only constant was the dealer changing the EGR.

Thoughts?

bugnout · **Posted:** Fri Oct 05, 2007 1:18 am

good question, but hard to answer. How many miles do you have on your CRD? How is it driving right now? what other indications do you have besides bad fuel mileage

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

bugnout wrote:

good question, but hard to answer. How many miles do you have on your CRD? How is it driving right now? what other indications do you have besides bad fuel mileage

Currently 30,000

It drives fine. It's never driven badly or seemed to have any problems other than the check engine light coming on then the dealer replacing the EGR twice.

It just gets bad mileage.

bugnout · **Posted:** Fri Oct 05, 2007 1:51 am

I'm not a mechanic, but I would suspect a sensor,

Low quality fuel can give you the same symptoms. Some parts of the country have 50 Cetane available, we only get 40 in my neck of the woods and I get significantly lower fuel mileage than when I run 50.

Do you notice more smoke from the exhaust? More smoke might indicate to much fuel, to little air, another clue it might be a sensor.

Maybe look at your turbo hoses for restriction. One of the other common mods is the EHM or Elephant Hose Mod. It disconnects the crankase vent from the turbo charge hose preventing oil from being introduced into that hose.

AZScout · **Posted:** Fri Oct 05, 2007 1:53 am

When they replaced the EGR, did they replace the Flow Control Valve as well? I seem to remember a thread that stated both should be changed at the same time.

dgeist · **Posted:** Fri Oct 05, 2007 8:23 am

AZScout wrote:

When they replaced the EGR, did they replace the Flow Control Valve as well? I seem to remember a thread that stated both should be changed at the same time.

That was my thought as well, Flow control, EGR, and MAP all need to be either fouled or in good working order. I'm imagining a picture of a functional EGR with a flow valve that's stuck, causing a starvation condition in combustion, along with a turbo spool-up that is messed up due to inaccurate pressure readings.... all goes back to that darned CCV getting oil all over everything :wink:

gmctd · **Posted:** Fri Oct 05, 2007 10:22 am

If the MAF is not dirty\plugged or simply defective, then I agree on the AFC\TV - would need to know the exact "EGR" DTC - if the AFV is stuck, ECM will sense restricted air flow thru the MAF, returning an EGR-ralated DTC such as 'EGR out of range for expected X value' - it has been reported that MrMoservice will replace the EGR assembly, rather than the AFV, that being the easier of the two.

Could also be a plugged soot-trap - way those things work is: the honey-comb matrix traps the soot and particulate, as exhaust gasses pass thru - nothing happens if the matrix temperature remains below a specific level - soot just piles up in the honeycomb until it eventually plugs up, restricting out-flow.

Take the vehicle up on the hiway for an extended jaunt at normal hiway speeds, EGT increases, the matrix heats up to cremation temp, the soot\particulate devolves into 'harmless' low-mass ash (say that three times in a row!), which then exits the tailpipe with the hot gasses and voila! - the engine can breathe again, air\fuel ratio improves, power and response improves, customer satisfaction is restored, and life is good

'Nuther words - maybe ya just need to blow'er out..............

dgeist · **Posted:** Fri Oct 05, 2007 11:03 am

gmctd wrote:

Take the vehicle up on the hiway for an extended jaunt at normal hiway speeds, EGT increases, the matrix heats up tp cremation temp, the soot\particulate devolves into 'harmless' low-mass ash (say that three times in a row!), which then exits the tailpipe with the hot gasses and voila! - the engine can breathe again, air\fuel ratio improves, power and response improves, customer satisfaction is restored, and life is good

I guess that's similar to the "blow its nose" method of bringin the engine up to operating temp for a little while, then pegging the tach up to about 3k+ for 10 or 15 seconds

gmctd · **Posted:** Fri Oct 05, 2007 11:11 am

Yep - that's good fer a gasser (patooie!), but not suitable for a Diesel system - soot is much larger and denser than the carbon powder that plugs the catalytic convertor in those systems - takes considerably more temp and duration to get the job done in a soot-trap, particularly, one that's only seen inner-city or inner-suburb jaunts with little hiway useage - takes a good hiway jaunt to burnit up 'n' blow'er out

Remember the stuff you cleaned off the MAP sensor - that's what's in the soot-trap...........................

Just an added note here, FYI - the SEGR ORM cures a lot of ailments in this Diesel system - word to the wise - or, in street-ese: word up...............

Joe Romas · **Posted:** Fri Oct 05, 2007 11:37 am

dgeist wrote:

gmctd wrote:

Take the vehicle up on the hiway for an extended jaunt at normal hiway speeds, EGT increases, the matrix heats up tp cremation temp, the soot\particulate devolves into 'harmless' low-mass ash (say that three times in a row!), which then exits the tailpipe with the hot gasses and voila! - the engine can breathe again, air\fuel ratio improves, power and response improves, customer satisfaction is restored, and life is good

I guess that's similar to the "blow its nose" method of bringin the engine up to operating temp for a little while, then pegging the tach up to about 3k+ for 10 or 15 seconds

Sometimes known as a Itilian Tuneup :lol:

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

Thanks for all the advice guys (gals?). I'm going to print this out and take it to the mechanic so he will know what to look for to get the problem resolved.

I can clean the MAP myself, but all this other stuff is a bit beyond my understanding. Hopefully, the mech will know what all this means.

I do love my CRD!

gmctd · **Posted:** Fri Oct 05, 2007 11:45 am

Hint: heading for the mechanic, take the long way around, via hiway - could be more than half the cure................

Guess it would be prudent to ask, right about now - I don't suppose the fuel economy dropped at about the same time as you started pulling the RV trailer?

jwalker · **Joined:** Wed Aug 29, 2007 7:43 pm **Posts:** 41

We don't pull a trailer with the CRD. We tow it behind a big ol' honkin' RV

The problem started last spring after we took it to the dealer to see why the check engine light kept coming on. That's when they said the computer diagnostic said it was a bad EGR. Since then, the EGR has been replaced twice.

It's gotten crappy mileage ever since then and the crappy mileage started litereally overnight after the senors were replaced.

We have driven it mostly on the interstate since then, so the "blowing it out" wouldn't seem to be the issue. We usually drive it at least 70-75 mph when we are on the interstate.

From reading on this forum, it would seem that some dealers don't have a good grasp on how the CRD actually needs to be maintained. I am hoping this has been the issue with my problem and a simple "education" is in order to fix the problem.

Really BAD fuel mileage :-( Advise PLEASE!!!

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