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

MAP Sensor cleaning issues...BE VERY CAREFUL!
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=51867
Page 1 of 4

Author:  GreenDieselEngineering [ Wed Apr 14, 2010 9:48 am ]
Post subject:  MAP Sensor cleaning issues...BE VERY CAREFUL!

We have been assisting several CRD owners the last few months with general issue resolution, CELs and maintenance. During that time it has become clear that the MAP sensor removal and cleaning routine is a potential problem. Many owners have had a check engine light for the fault code P0069. This generally occurs after cleaning in most cases.

P0069 is an implausibility fault on the MAP sensor that can occur after it completes a comparison check with respect to the atmospheric pressure sensor. If the exposed resistor is touched, bumped, rubbed, etc. during the cleaning process it is easily damaged and can shift the MAP pressure reading. Many folks on LOST claim a performance increase by cleaning the MAP, but the risk of damaging the sensor when cleaning is high as it is a very sensitive component. It is important for this sensor to be accurate or it may be possible to have overboosting of the turbo and a reduced lifespan due to overspeeding. Be very careful when cleaning this sensor!

FAULT DETECTION AND REACTION
This error puts the vehicle in limp-home mode as a protection for the turbo. The fault is only detected at idle (below 850 rpm) and the MAP reading must be +/- 2 psi different than the atmospheric sensor for more than 15 seconds in order to set the fault. The fault is healed if the difference between the readings is less than 2 psi for more than 0.5 seconds. The diagnostic check can only occur at this operating zone since the manifold air pressure at idle should be very close to atmospheric pressure.

If the MAP sensor has shifted to read almost 2psi higher, the actual level of boost in the intake manifold in driving conditions will be 2psi lower than when the sensor was new. This lower boost will negatively effect fuel economy, increase smoke levels and reduce performance feel. If the MAP sensor reading has shifted to read almost 2psi lower, the actual level of boost in the intake manifold in driving conditions will be 2psi higher than when the sensor was new. This higher boost will increase fuel economy, reduce smoke slightly and provide a little increase in performance. The problem with a shift in this direction is a potential for overspeeding the turbocharger at wide open throttle conditions. Example: Let's say the desired boost is 19psi gage at WOT, with a negative shift the MAP will read about 17psi, so the turbo must spin faster to achieve the setpoint boost pressure of 19psi and the real boost will be around 21psi. In certain situations this requires the turbo to spin roughly 10,000 rpm faster than it would normally be spinning with a MAP sensor that reads correctly.

If you experience this error code it may require purchasing a new MAP sensor. The service manual has some discrepancies regarding the MAP part number and picture. The part could be 5101120AB - MAP sensor at $45.51 or it could be 68031593AA - Air temp sensor at $84.30. There have been some topics regarding part number issues for the MAP sensor in the past, but we are having issues finding them at this time. Maybe someone who ordered a MAP sensor in the past could post up the correct part number to help clarify the situation.

Awareness and preventative maintenance is always a good idea with the CRD, we just want everyone to be aware of the potential issues associated with cleaning the MAP sensor.

Thanks, GDE

Author:  flman [ Wed Apr 14, 2010 10:18 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

I leave my alone for the most part, cleaned them once around the time I got the GDE tunes, and I will leave them alone until they exhibit a problem. After all they are really just thermistors that sense temperature? If I am wrong correct me please.

You know the old saying, "If it aint broke, keep fixing it until it is".

Author:  linewarbr [ Wed Apr 14, 2010 11:27 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

The part number for the CRD's MAP sensor is 68031593AA. A member posted this in the Tech section: viewtopic.php?f=98&t=44901

Author:  geordi [ Wed Apr 14, 2010 11:34 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

And if you get it from a dealer, I WISH that had been the price! $171 was what I was charged... For something that did nothing to fix the problem I've been having. :banghead:

BUT: You won't need to clean the dang thing anymore, if you simply do an EHM or provent. Get that oil mist outta the intake, and it won't glop up the MAP anymore. Mine has been Shiny Special Clean for several thousand miles now, since the EHM... When it had been a wet oily mess (but not solid chunks) with just the SEGR.

Author:  Joe Romas [ Wed Apr 14, 2010 12:25 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

geordi wrote:
And if you get it from a dealer, I WISH that had been the price! $171 was what I was charged... For something that did nothing to fix the problem I've been having. :banghead:

BUT: You won't need to clean the dang thing anymore, if you simply do an EHM or provent. Get that oil mist outta the intake, and it won't glop up the MAP anymore. Mine has been Shiny Special Clean for several thousand miles now, since the EHM... When it had been a wet oily mess (but not solid chunks) with just the SEGR.



Geordi.

Did you per chanch try mopoarts (or whatever their namd is) online? The reason I ask is 2 months ago the ignition lock went bad on my Cherokee. I bought one at a local dealer as I needed it then. After I finished putting it on I looked on line and found they had charged me DOUBLE THE MSRP :shock: They charged me $128 and the online place has the msrp as $64 and their price is $53 :oops:

So the dealer screwed me but it won't happen again.

The moral of the story is to shop around because it looks like they are price gouging on parts to stay open :goink:

Author:  BVCRD [ Wed Apr 14, 2010 2:08 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Cleaned mine way back at 18,000 miles. Since ULSD came out, haven't had to clean it sense.

Author:  geordi [ Wed Apr 14, 2010 5:47 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Joe Romas wrote:
geordi wrote:
And if you get it from a dealer, I WISH that had been the price! $171 was what I was charged... For something that did nothing to fix the problem I've been having. :banghead:

BUT: You won't need to clean the dang thing anymore, if you simply do an EHM or provent. Get that oil mist outta the intake, and it won't glop up the MAP anymore. Mine has been Shiny Special Clean for several thousand miles now, since the EHM... When it had been a wet oily mess (but not solid chunks) with just the SEGR.



Geordi.

Did you per chanch try mopoarts (or whatever their namd is) online? The reason I ask is 2 months ago the ignition lock went bad on my Cherokee. I bought one at a local dealer as I needed it then. After I finished putting it on I looked on line and found they had charged me DOUBLE THE MSRP :shock: They charged me $128 and the online place has the msrp as $64 and their price is $53 :oops:

So the dealer screwed me but it won't happen again.

The moral of the story is to shop around because it looks like they are price gouging on parts to stay open :goink:


Short answer is no, I didn't check them first. I was on the road and the stupid thing kept going into limp mode while driving. I have since come to the conclusion that the wiring to the AIRBOX map sensor (that stupid Mercedes logo sensor) was somehow broken internally, and YES, it DOES MAKE A DIFFERENCE even at highway speeds.

What that thing is doing at that point, I will never know. But with intermittent wiring, it was pissing off the computer enough that it kept cutting the power at speed. I would reboot the computer (key-off while in gear) and it would be fine once I went back to key-on for about 5-6 minutes... And then I would feel the power cut again.

Considering that the power-loss-with-big-smoke-clouds happened right after replacing that sensor, I decided that the sensor wasn't the cause. But apparently at the time, just messing around under the hood moved the wiring harness enough to stop it from limp-moding at speed.

That was several months ago, and I have since replaced the airbox map and maf sensors. Still have the problem, but less severe now. If I ever DO get it solved, I'm expecting race-car performance and 400 mpg from this thing for all the work and money I've shoved at it.

These things are more work to support than a supermodel girlfriend!

Author:  dritchie [ Wed Apr 14, 2010 8:59 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Hmmmm, I've had that code 5 times since I got the eco tune 2 weeks ago. Never saw it before, but like I said in a previous post, I have always had a check engine light on from the MAF sensor being unplugged, but P0069 never showed up on my scangauge when I checked it before the tune. :?:

Dave

Author:  kapalczynski [ Wed Apr 14, 2010 11:02 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

I have cleaned it only once. This was after having issues with loosing all boost during vehicle operation. Engine shutdown/restart and issue dissapeared temporarily, cam back later on. After cleaning this issue has not occurred again. I now have the GDE tune adn don't expect cleaning to be necessary as often as factory. I only used chemical spray cleaner, never a brush, etc. Hopefully this way will not disturb the sensor operation.

On another note, unfortunately my turbo may have been overspeeding from factory with the intercooler defect that was bleeding off boost. Factory intercooler haqd a hole in it I believer to be a factory defect. Sensor will still attempt to achieve proper boost, this could have been overspeeding the turbo to attempt to achieve the boost due to the boost leak.

Be sure to check your intake system for leaks every once in awhile. :)

Author:  Big Montana [ Wed Apr 14, 2010 11:08 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

kapalczynski wrote:

Be sure to check your intake system for leaks every once in awhile. :)


On that note, what would I look for? I got out of my Jeep quickly the other day after turning it off, and I heard a hissing noise from the front end. I even put my ear to the grill. It only lasted about 3-4 seconds. I remembered your problem and I was wondering if that was the air escaping from the intercooler. I really don't see how it can hold pressure after the air shuts off, but I was wondering.

Author:  geordi [ Wed Apr 14, 2010 11:35 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

I will say that with both a boost gauge and an EGT gauge (that I didn't have before the engine replacement) I am less worried about a turbo overspeed than I might have been before. If something happens to this turbo, I will know about it instantly, and cut the motor off before it has a chance to pump any oil out into the exhaust. I can replace a turbo fairly easily now, having done it already.

However... Should it do that to me for some reason... It will probably be the last failure I will endure with this vehicle. I'm not pushing the limits on it, not asking 500+ lbs of torque or flogging it constantly while towing 10k lbs. If it is this fragile, maybe there is something else going on, like a design flaw. Probably related to that dang EGR system, if anything.

Author:  BrianUnderwood [ Thu Apr 15, 2010 12:05 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Yeah... Don't use a toothbrush to "help" clean the sensor, or any brush for that matter. I wasn't thinking, and now the sensor is totally busted. P0069 code is intermittent, will come on, then clear in a day or so, then come on again. New sensor coming in tomorrow. Any advice on installation? Thanks GDE for all your efforts in educating morons like me!

Author:  LibertyCRD [ Thu Apr 15, 2010 7:38 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

What about just spraying it down real good with electrical parts cleaner from Radio Shack and calling it a day? Won't that work without damaging anything?

Author:  Goglio704 [ Thu Apr 15, 2010 7:40 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

flman wrote:
I leave my alone for the most part, cleaned them once around the time I got the GDE tunes, and I will leave them alone until they exhibit a problem. After all they are really just thermistors that sense temperature? If I am wrong correct me please.

You know the old saying, "If it aint broke, keep fixing it until it is".


It is my understanding that the MAP sensor detects both temperature and pressure. I think a thermistor probably handles the temperature portion of this sensor, but there has to be some kind of pressure transducer to measure pressure doesn't there? Inquiring minds want to know.

Author:  linewarbr [ Thu Apr 15, 2010 10:43 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Big Montana wrote:
kapalczynski wrote:

Be sure to check your intake system for leaks every once in awhile. :)


On that note, what would I look for? I got out of my Jeep quickly the other day after turning it off, and I heard a hissing noise from the front end. I even put my ear to the grill. It only lasted about 3-4 seconds. I remembered your problem and I was wondering if that was the air escaping from the intercooler. I really don't see how it can hold pressure after the air shuts off, but I was wondering.


That is most likely the vacuum reservoir for the turbo making that noise. It is behind the airbox, and has a little filter on it that looks like an inline fuel filter. When you cut off your engine, the solenoid will pull air through that filter and into the vacuum reservoir to use the next time you start it.

You would hear a leak from the intercooler if you stand there with the hood open and listen while someone revs the engine - even then it would be tough because the turbo won't spool as much at idle as it will under load. A more likely sign of an intercooler leak would be engine oil (introduced by the CCV, if it is still active) somewhere on the aluminum parts of the intercooler.

Author:  linewarbr [ Thu Apr 15, 2010 10:49 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

LibertyCRD wrote:
What about just spraying it down real good with electrical parts cleaner from Radio Shack and calling it a day? Won't that work without damaging anything?



Good ole' #2 or chlorine-free brake parts cleaner.

I've only pulled mine once since getting the GDE tune and installing a CCV diverter. It was just as pristine as when I pulled and cleaned it prior to the modifications, so I have not removed it since then. That was about 30,000 miles ago.

Author:  flman [ Thu Apr 15, 2010 12:14 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Goglio704 wrote:
flman wrote:
I leave my alone for the most part, cleaned them once around the time I got the GDE tunes, and I will leave them alone until they exhibit a problem. After all they are really just thermistors that sense temperature? If I am wrong correct me please.

You know the old saying, "If it aint broke, keep fixing it until it is".


It is my understanding that the MAP sensor detects both temperature and pressure. I think a thermistor probably handles the temperature portion of this sensor, but there has to be some kind of pressure transducer to measure pressure doesn't there? Inquiring minds want to know.


I was thinking it was comparing air temp at the air filter intake to the temperature at the map sensor, and the computer does the rest of the math? It does not look at that complex, and just a little bit off crud would throw of the pressure if that was the case. But I will not swear by it :?:

Author:  Squeeto [ Thu Apr 15, 2010 1:39 pm ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Quote:
Many owners have had a check engine light for the fault code P0069. This generally occurs after cleaning in most cases.


I am curious how many have had a P0069 fault code after cleaning their boost (map) sensor and don't have the GDE tune?

Author:  WolverineFW [ Fri Apr 16, 2010 12:51 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

Squeeto wrote:
Quote:
Many owners have had a check engine light for the fault code P0069. This generally occurs after cleaning in most cases.


I am curious how many have had a P0069 fault code after cleaning their boost (map) sensor and don't have the GDE tune?



I am curious which method all the people that developed this problem had cleaned their MAP sensor and what substance they used to clean it?

Author:  TJ2 [ Fri Apr 16, 2010 3:33 am ]
Post subject:  Re: MAP Sensor cleaning issues...BE VERY CAREFUL!

WolverineFW wrote:
Squeeto wrote:
Quote:
Many owners have had a check engine light for the fault code P0069. This generally occurs after cleaning in most cases.


I am curious how many have had a P0069 fault code after cleaning their boost (map) sensor and don't have the GDE tune?



I am curious which method all the people that developed this problem had cleaned their MAP sensor and what substance they used to clean it?


+1 I cleaned the MAP/boost pressure sensor right after I got the Liberty. No 0069 code. I got the Eco-tune. . .no 0069 code.

It has been stressed that stuff containing chlorine may be bad. I used 'carby cleaner' as the Aussies suggested and haven't seen any problems.

Page 1 of 4 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/