Dealer wants to "De-Carb" and clean MAS

zoomie · **Joined:** Tue Jun 15, 2010 2:12 pm **Posts:** 47

Did a search but didn't find this specifically.

Dealer wants to do a "De-Carb" and Mass Airflow Sensor clean on my 2010 KK with 37,000 miles and they want over $250 for the service. The truck is running fine.

They also wanted to changed the tranny fluid but when I checked the book it says to check the fluid and change if necessary. I didn't have them do that.

Does this de-carb thing sound legit? Is it just a can of injector cleaner that I can do?

Cheers

Scar0 · **Posted:** Tue Jan 10, 2012 6:41 pm

The 2010 Jeep Liberty does not have a mass airflow (MAS/MAF) sensor, it uses a combination of a manifold absolute pressure (MAP) sensor (in the manifold), intake air temperature (IAT) sensor (in the tube from the air-box to the carb), and 4 oxygen (O2) sensors. These sensors communicate with the engine control unit (ECU), which calculates the correct amount of fuel to inject into the cylinders.
The MAP sensor on the 3.7 is located on the front bottom of the intake manifold. Not sure how it would get dirty?
Sounds like a scam to me! Dump in a can of injector cleaner and off you go.

tjkj2002 · **Posted:** Tue Jan 10, 2012 6:59 pm

A fuel induction cleaning is well worth it.Just adding injector cleaner in the gas tank is only one part of a fuel induction cleaning.There are 2 other steps.In mordern FI engines no fuel travels through the intake as one injector is located right above each intake valve.When you turn the engine off some of the intake valves will be open and the combustion gases left in those cylinders will back up into the intake(and TB/IAC) and leave a layer of carbon.After time thise layer of carbon builds up and does effect your performance and mpg's,it's a gradual reduction so you will never really "feel" the effects.A proper induction cleaning cleans all that carbon build up from inside the intake manifold,cleans the TB and IAC ports,and the last step is a injector cleaner in the gas tank to clean the injectors.Seafoam is not a good induction cleaning agent,to harsh for the plastic and not really that good of a cleaner for carbon build up.

There are many engines that do use MAF sensors and some do not,the dealer just labels the cleaning for MAF systems which are directly effected from carbon build up and oiled air filters.I have not run into it yet on a 3.7 but I know carbon build up on the GM's 4.2 I6 has a major effect on it's MAP sensor,there's even a TSB for it and the fix is a induction cleaning.

gren71 · **Posted:** Tue Jan 10, 2012 7:27 pm

how often does this really need to be done though?

My wife's dealer wanted to clean her fuel injectors and i said not to do it. She only has 15k on her truck...seems like they should be no where near that dirty.

tjkj2002 · **Posted:** Tue Jan 10, 2012 7:37 pm

gren71 wrote:

how often does this really need to be done though?

My wife's dealer wanted to clean her fuel injectors and i said not to do it. She only has 15k on her truck...seems like they should be no where near that dirty.

Depends on driving style.

Lots of stop and go and/or short trips I'd say once a year or 15k-20k miles.Do alot more highway driving or very long trips do right before plug change(every 30k).

Scar0 · **Posted:** Wed Jan 11, 2012 12:57 am

Makes sense, but what are the 2 other steps?
How do you clean the inside of the intake manifold without removing it?
Some kind of spray in the throttle body?
If seafoam is bad., what should we use in the tank?

zoomie · **Joined:** Tue Jun 15, 2010 2:12 pm **Posts:** 47

tjkj2002 wrote:

A fuel induction cleaning is well worth it.

Thanks for the feedback guys.

What is a reasonable charge for this? Does it have to be done at the dealer or is it something I can do?

racer1 · **Posted:** Wed Jan 11, 2012 6:39 pm

There are do it yourself kits, but the good ones are not cheap. I used the Justice Brothers pro system and it worked good. I will have to say that I did some horse trading with a salesman so I didn't really pay out of pocket. There chemicals work quite well.

Dave

remdawg · **Joined:** Fri Nov 12, 2010 2:05 pm **Posts:** 204

It's probably like a $30 DIY project. I did mine at 60k.

Two cans of sea foam (one for gas tank, half for oil and other half in brake booster) and a can of sea foam deep creep for the throttle body.

You can find how to's on YouTube. I would change oil and spark plugs shortly after doing this.

tjkj2002 · **Posted:** Wed Jan 11, 2012 9:10 pm

Scar0 wrote:

Makes sense, but what are the 2 other steps?
How do you clean the inside of the intake manifold without removing it?
Some kind of spray in the throttle body?
If seafoam is bad., what should we use in the tank?

The 2nd step is introducing a cleaner into the manifold via vacuum port in a very fine mist,16oz over a 30min period with the engine running at about 1200rpm's.The 3rd step is t take the air tube off the TB and clean it(while running),making sure to get the IAC ports.

zoomie · **Joined:** Tue Jun 15, 2010 2:12 pm **Posts:** 47

tjkj2002 wrote:

The 2nd step is introducing a cleaner into the manifold via vacuum port in a very fine mist,16oz over a 30min period with the engine running at about 1200rpm's.The 3rd step is t take the air tube off the TB and clean it(while running),making sure to get the IAC ports.

That's the stuff, Thanks Guys.

Scar0 · **Posted:** Fri Jan 13, 2012 5:32 am

Great info tjkj! Thanks!

zoomie · **Joined:** Tue Jun 15, 2010 2:12 pm **Posts:** 47

tjkj2002 wrote:

A proper induction cleaning cleans all that carbon build up from inside the intake manifold,cleans the TB and IAC ports,and the last step is a injector cleaner in the gas tank to clean the injectors.Seafoam is not a good induction cleaning agent,to harsh for the plastic and not really that good of a cleaner for carbon build up.

Tjkj, what agent do you recommend for a diy job? Also can you fill us in on what vacuum hose to use when introducing the agent in to the injectors?

tjkj2002 · **Posted:** Mon Jan 16, 2012 8:08 pm

zoomie wrote:

tjkj2002 wrote:

A proper induction cleaning cleans all that carbon build up from inside the intake manifold,cleans the TB and IAC ports,and the last step is a injector cleaner in the gas tank to clean the injectors.Seafoam is not a good induction cleaning agent,to harsh for the plastic and not really that good of a cleaner for carbon build up.

Tjkj, what agent do you recommend for a diy job? Also can you fill us in on what vacuum hose to use when introducing the agent in to the injectors?

http://www.edwardsracingengines.com/qmi.html

Scroll to the bottom of the page in the link above.What we use at work and will need to bottle to the left also to properly deliver into the intake.Most common place to tie into is the main vacuum line right off the brake booster.Besides having to buy that bottle it's not very expensive to do yourself,heck we only charge like $80 for the service at work.

zoomie · **Joined:** Tue Jun 15, 2010 2:12 pm **Posts:** 47

tjkj2002 wrote:

Besides having to buy that bottle it's not very expensive to do yourself,heck we only charge like $80 for the service at work.

Thanks again TJ - That's what I need. My dealer here in Guelph Ontario is pretty aggressive. I get them to do oil changes when it's really cold and they always come up with some service I need. The time before this It was change the oil in the tranny at 37k miles. My book says just check it and change when needed. When I called them on it they said I was right. They want over $200 to the de-carb service.

Diggerfreek · **Posted:** Wed Jun 20, 2012 1:31 am

[quote="psrose"]I have not run into it yet on a 3.7 but I know carbon build up on the GM's 4.2 I6 has a major effect on it's MAP sensor,there's even a TSB for it and the fix is a induction cleaning.

bagwell · **Joined:** Tue Nov 29, 2011 11:40 pm **Posts:** 64

everything I have heard about seafoam has been positive as far as being a good cleaner....it was a must-do procedure on a Mini Cooper S intake that I owned.

tjkj2002 · **Posted:** Thu Jun 21, 2012 4:58 pm

bagwell wrote:

everything I have heard about seafoam has been positive as far as being a good cleaner....it was a must-do procedure on a Mini Cooper S intake that I owned.

Seafoam as a automotive cleaner is like comparing dail handsoap and dawn dishsoap,it sucks when compared to much better cleaners on the market.You think it's working from all the smoke it makes but in reality it really does not clean very good.

Dealer wants to "De-Carb" and clean MAS

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