LOST JEEPS
http://www.lostjeeps.com/forum/phpBB3/

2.5 crd usa spec, high fuel consumption and not pulling righ
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=3&t=90948		 Page 1 of 1
Author:  ztig [ Fri Feb 07, 2020 10:05 am ]
Post subject:  2.5 crd usa spec, high fuel consumption and not pulling righ
Hello, my friend has a 2004 cherokee 2.5 crd and it has high fuel consumption, around 12.2l/100 km or 19.3 mpg us. I think there is an issue with the wastegate but now the weather doesn't let us do anything outside. I bought a boost gauge and want to put a T on the wastegate pipe and measure the boost but we don't know how much boost it should make.
I suspect the wastegate because there are no hissings or other sounds coming from the engine bay and the piping looks fine. Also, if you WOT from 1500 rpm, you feel the car starting to pull 'properly' after 2500 rpms..but still there doesn't seem to be any torque kicks. I think this is not normal as max torque is supposed to be at 2000 rpm.

Does anyone know at how much boost should the wastegate begin to open?

Any help is appreciated, thanks
Author:  layback40 [ Fri Feb 07, 2020 4:17 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
ztig wrote:
Hello, my friend has a 2004 cherokee 2.5 crd and it has high fuel consumption, around 12.2l/100 km or 19.3 mpg us. I think there is an issue with the wastegate but now the weather doesn't let us do anything outside. I bought a boost gauge and want to put a T on the wastegate pipe and measure the boost but we don't know how much boost it should make.
I suspect the wastegate because there are no hissings or other sounds coming from the engine bay and the piping looks fine. Also, if you WOT from 1500 rpm, you feel the car starting to pull 'properly' after 2500 rpms..but still there doesn't seem to be any torque kicks. I think this is not normal as max torque is supposed to be at 2000 rpm.


Does anyone know at how much boost should the wastegate begin to open?

Any help is appreciated, thanks



Have you tried disconnecting the line to the wastegate actuator, plug the supply line & see if it behaves differently? Dont go WOT during test. You risk blowing it up if you over boost.

If you do the test you want to do, expect pressures of up to about 15 psi. It may go a little higher under certain conditions.
If you hold the leaver on the actuator you should be able to feel the spring tension holding it shut but you should be able to move the leaver a little. If you apply carefully about 30 psi to the actuator you should see the leaver move. This is best done with a hand pump. Do this with engine cold & not running. The waste gate could be jammed open.

Be very aware that the turbo is different to the 2.8

Also would be worth checking the EGR to make sure it has not failed open or leaking.
Author:  ztig [ Fri Feb 07, 2020 5:37 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
I was informed of this just a few days ago..will try to plug that line and see, or better connect the gauge.

Hm, forgot to say that we plugged the egr vacuum but we'll check the egr and also maybe try to make a flange to delete the egr completely.
I know this is different from the 2.8 as its not vnt, i have some experience with vnt but none with wastegate as its not common at all here.
Hopefully the weather will get better, will report back after we can connect the gauge and do what you said. Thanks.
Author:  layback40 [ Sat Feb 08, 2020 7:21 am ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
I have used a piece of metal food can as a blank on EGR's. Some of the export XJ's came with a diesel (VM425 not CRD). I had one that had the EGR fail internally & send small pieces of metal through the engine. Also have had a turbo waste gate jam shut. I could get 30psi boost. Not good for the engine though.
Author:  ztig [ Sat Feb 08, 2020 12:15 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
Ok, so we've put the boost gauge on the wastegate pipe..it got up to 1.5 bar boost, we were afraid to go higher cause the point was proven.. the wastegate is closing properly and the egr doesn't remain open. It seems like its pulling the same...so I really don't know, maybe this is how its supposed to pull..but it gets a too low mpg. Do you happen to know the average mpg for this engine?

Now, I forgot to read the codes before this operation..we got a cel. The codes are: p0836, p1685, p0579 and p0235( i suppose this triggered the cel?).

I usually do logs to check everything fuel and boost related..but I don't know any cabale capable to do this on the jeep. Is there any?

Thanks.
Author:  layback40 [ Sat Feb 08, 2020 5:54 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
You can google the codes.
Do you have black smoke out the exhaust pipe?
Author:  ztig [ Sun Feb 09, 2020 6:11 am ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
I've googled them..only p0235 is boost related
Turbo/Super Charger Boost Sensor A Circuit

Basically, my question was.. Was the cel triggered by this error or not? We never drove over a mile with the wastegate closed..but after half a mile the cel was there.... So did this error trigger it or not? It's not an overboost error so i suppose it could have been there before.

Nothing you can notice in the mirror, i've seen a puff not long ago, but nothing in the mirror.
Author:  layback40 [ Sun Feb 09, 2020 7:53 am ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
Have you cleaned the MAP sensor? You can with sensor cleaner. It could be causing the cel. Have you checked the turbo for movement in the shaft?
I am just going through a couple of standard things.
Author:  ztig [ Tue Feb 11, 2020 2:48 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
No, the weather is all bad again...
Did not check the turbo, all we did was to put the gauge and then removed it. Honestly, I no longer think there might be an issue other than the high fuel consumption..

He did 0-62 and it was slower with 0.5 sec-1 sec(14-14.5) than official data, but he had the trunk full with tools. Nonetheless, I've edited the ecu software a bit and now its a second faster with no tools(12.5) than official time(13.5).

Are you aware of any diagnostic tool that is able to display live data on the 2.5 crd? I've looked at a lot of tools but even the OBD Jscan app shows just Cherokee/Liberty KK so no point in buying a scanner compatible with that.
Author:  Billybob [ Wed Feb 12, 2020 12:50 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
Hi ztig, I answered your other post here. in the Liberty CRD Love That Torque section.

Check the following for bad power:

Check the rubber CAC hoses going from turbo to Intercooler and from Intercooler to Intake manifold do not have any splits, cracks or holes in them.
These do fail and usually a break causes low power and lots of black smoke coming out the exhaust.
This happened to me....limped home and saw a big split in one house....taped it up with Duct tape until I could get new ones from the Agents.....this was years ago!

Most CRD owners do not use the OEM hoses but get SAMCO or Mishimoto silicone hoses...more robust and you can get different colors.....these are not available here in SA!

If you do try to get non OEM hoses as above be aware that the diameter of our Export 2.5 CRD hoses is smaller than for the 2.8 CRDs so make sure you get the correct ones.

Your Intercooler may be blocked up with oil and gunge thereby stopping the flow....I will leave it to the real experts here to advise you on how to correct this.

Make sure your MAP sensor is indeed very clean. Our 2.5 CRDs use a Bosch Map... Bosch PN is on the sensor. It is held on by two medium size Allen bolts....USA models have a different MAP held on by a single larger Allen bolt. Make sure the rubber O ring under the MAP sensor is OK.
This is a very delicate sensor...do not use brushes or cloths on it...best to spray it with Brake Cleaner.
This Map measures Boost Pressure as well as Air Intake Temperature. I had a bad wire for this second wire going from pin #2 on the sensor to the ECM....gave me major loss of power and the Engine Icon lighting up on the Right Top of the cluster...I will check which code I got.

Make sure your fuel and air filters are clean...I had a mouse make a home inside my Air Filter Housing!

Next to the air filter housing you will see a small black plastic solenoid with a small paper filter hanging down from it and a two wires connected from it....this solenoid actuates the "wastegate" and you cannot disconnect the wires going to the solenoid. You can however pull of one of the small rubber hose going to it...preferably the outer hose. Now take a small self-tapping screw and block this outer plastic nipple then re-fit the rubber hose over the screw head.
This stops the wastegate/EGR from actuating and gives you more power.

Ok I do not have 2004 Jeep KJ Service Manuals...the 2003 will be close enough but wire colors may be different.
But download the 2003 Jeep KJ Service Manuals here but very important is to download the section: "2.5_2.8 export diesel" as it contains very useful information for our Diesels such as the Error Codes and what to do about them...tells you voltages to measure etc. but we do not have the Dealers OBIII reader that they refer to!

You can get stored CEL codes with the "key" trick:

Without starting the engine rapidly turn ignition ON/OFF 4 times.
After the 4th ON action leave the ignition ON.
The Odometer Display will read out stored codes from the oldest...which may no longer be relevant...to the newest. Codes are only stored once so multiple errors of P0123 will only show once.
You cannot erase the codes with the Key trick.

I will look into your codes and get back to you. :wink:

Read SAMS NOOB GUIDE at the top of Love That Torque section...mainly covers 2.8 USA models but some good info there...such as my EGR disable trick! :)

http://www.colorado4wheel.com/manuals/Jeep/KJ/

These manuals give you some info. on how things work and section 8W has the wiring diagrams.

OK using the 2.5_2.8 export diesel manuals above:

P0836 Transfer Case Plausibility....this is the switch that senses if you are in 2 wheel or 4 wheel drive.

P1685.. SKIM invalid. This means the ECM was not happy with the SKIM code sent to it by the SKIM module on top of the steering column which reads the chipped code.

P0579.. Speed control switch plausibility. I presume you have Cruise Control fitted.

P0235.. Boost Pressure Sensor....could be the MAP sensor.

Go to the page number that these codes direct you to in the same manual. :wink:
Author:  WWDiesel [ Wed Feb 12, 2020 4:00 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
Your Codes:
P0235 - Turbocharger Boost Sensor 1 Circuit
P0579 - Cruise Control Related Malfunction
P0836 - Four Wheel Drive (4WD) Switch Circuit
P1685 - JEEP - Invalid SKIM Key

Replace the MAP sensor, clear the codes and see if any return. :idea:
A bad or misreading MAP sensor can certainly affect fuel mileage!
Author:  ztig [ Wed Feb 12, 2020 6:23 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
@Billybob thank you for all the info, i'll look over the manual. I'll clean the map sensor asap, all filters were recently replaced. And there is no heavy smoke, the hoses were visually checked and seem ok, no splits, cracks or holes visible.
@WWDiesel thank you too.

To be noted, as I previously said, we put a boost gauge and left the wastegate completely closed and after half a mile, check engine light lit up. I never read the codes before, so I thought P0235 is related to the overboost it had with the closed wastegate?! Can you confirm or deny?

Is there any way I can delete the P0235 and see if it appears again?
Author:  Billybob [ Thu Feb 13, 2020 2:32 am ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
ztig wrote:
@Billybob thank you for all the info, i'll look over the manual. I'll clean the map sensor asap, all filters were recently replaced. And there is no heavy smoke, the hoses were visually checked and seem ok, no splits, cracks or holes visible.
@WWDiesel thank you too.

To be noted, as I previously said, we put a boost gauge and left the wastegate completely closed and after half a mile, check engine light lit up. I never read the codes before, so I thought P0235 is related to the overboost it had with the closed wastegate?! Can you confirm or deny?

Is there any way I can delete the P0235 and see if it appears again?


Pretty much impossible to clear Codes on the early Export CRDs because PCI Bus is used.
There have been many threads on this matter that I have been reading since I bought my 2002 Export 2.5 L CRD.

Nobody that I know of has found a way to clear these codes...Bosch Agents here in SA shook their heads after taking one look at the Bosch ECM.

So you would need to drive into a Jeep Dealer and ask them to only clear the codes for you with their DBIII reader. :wink:

Dealers here in SA are useless. In about 2009 before I even joined any Jeep forums I had the Battery light come on solid. Owner's Manual said it was the Alternator not charging. I measured the battery voltage and charging voltage and they seemed OK
to me so I took the Jeep to an Auto Electrician who tested the alternator as OK. He suggested I take it to the Jeep Dealers and ask them to reset the Battery lamp...this I did.
After sitting in the waiting room for an hour I slipped into the workshop area and found a young "Technician" scratching his head with the main wiring harness all exposed in the engine bay! This Technician said that he thought that the ECM was faulty but they did not have one in stock.

There were two other CRDs standing nearby in for a Service but the "Technician" said he could not "borrow" their ECMs as they were the wrong models! :roll:
Nice to know that if you take your Jeep to the Dealers they will borrow parts off your Jeep to fault-find another Jeep next to it! :shock:

I told the idiot to wrap it all up...which he did badly...and paid for his time.
I then got onto the internet on various Jeep forums including this one and found a link to the 2002 Jeep KJ Service Manual and soon traced the wiring to the Battery Temperature Sensor under the battery...this was missing its ground somewhere inside a splice in the main harness. I added my own ground to chassis.

That was the start of my journey into fixing my own Jeep and helping other Jeep owners with their problems.....especially Wiring Issues!

I qualified in Electrical Engineering Light Current in 1972 and worked in Support for IBM for 8 years and then a Hitachi Mainframe company for 24 years...including large Industrial Robots!

So I know my way around the KJ wiring and have been very happy to help out fellow Jeep owners around the world with their problems...keeps my mind more or less working in my retirement! :wink:

I have now pulled off about 13 wiring errors on my Jeep after a front collision damaged the main harness.

The Local Jeep dealers only touched my Jeep when I needed the Cam Belt to be replaced....this dealership has gone out of business but unfortunately the Jeep/Fiat franchise has moved to an even worse bunch! :x
Author:  Kirkwall [ Fri Feb 14, 2020 5:27 pm ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
I know that such things happen unexpectedly. Somehow I forgot to cover the car, and at night the frost hit and I thought that I would no longer drive it. And what infuriates me, this often happens unexpectedly and not all weather forecasts talk about it. I found a good site with a forecast, while it seems to be very critically wrong https://world-weather.info/forecast/usa/boyce/. (I'm from Boyce)
Author:  layback40 [ Sat Feb 15, 2020 4:52 am ]
Post subject:  Re: 2.5 crd usa spec, high fuel consumption and not pulling
Kirkwall wrote:
I know that such things happen unexpectedly. Somehow I forgot to cover the car, and at night the frost hit and I thought that I would no longer drive it. And what infuriates me, this often happens unexpectedly and not all weather forecasts talk about it. I found a good site with a forecast, while it seems to be very critically wrong https://world-weather.info/forecast/usa/boyce/. (I'm from Boyce)

Thanks for that Kirk. It even works for small towns in Australia. Much better than our local government service.
Page 1 of 1 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/