05 liberty crd boost hesitation

gibsonsk · **Joined:** Mon Nov 13, 2017 6:36 pm **Posts:** 7

Ok guys I have read a lot on here, days in-fact. When I got this puppy it had a turbo that screamed when it came in, as in screeching noise. Replaced turbo after the rebuild kit failed. Did EGR delete. Replaced the Intake hose and both intercooler hoses. and both vacume control valves on the right fender.
Here is the problem when you hit the pedal the turbo actuator moves but not far you have to pump the pedal to get the turbo to spool up. sitting still or driving. If I bypass the vac control solenoid with the filter on it the turbo spools up but just doesn't put out what it should. Any Ideas

flash7210 · **Posted:** Sun Dec 16, 2018 8:57 pm

The problem is most likely the MAP sensor on top of the engine.
(Not the MAF sensor on the air filter box lid)

Turbo boost is controlled by the computer.
The MAP sensor senses boost pressure in the intake manifold.
If the MAP sensor is sending a faulty reading, you won’t get the appropriate amount of boost.

You need to scan for codes. A overboost condition with put it into limp mode with reduced power and set a code.

Also, it’s almost impossible to diagnose a turbo boost problem without a boost gauge.
The easiest way to do that is with a OBD scan tool that can read live sensor data from the MAP sensor.

WWDiesel · **Posted:** Sun Dec 16, 2018 9:29 pm

flash7210 wrote:

Also, it’s almost impossible to diagnose a turbo boost problem without a boost gauge.
The easiest way to do that is with a OBD scan tool that can read live sensor data from the MAP sensor.

But if a MAP sensor is defective and giving erroneous pressure signals to the ECM, then the only way to read true boost pressure is with a mechanical boost gauge connected to the intake manifold to compare pressure readings.... :juggle:

flash7210 · **Posted:** Mon Dec 17, 2018 8:08 am

WWDiesel wrote:

flash7210 wrote:

Also, it’s almost impossible to diagnose a turbo boost problem without a boost gauge.
The easiest way to do that is with a OBD scan tool that can read live sensor data from the MAP sensor.

But if a MAP sensor is defective and giving erroneous pressure signals to the ECM, then the only way to read true boost pressure is with a mechanical boost gauge connected to the intake manifold to compare pressure readings.... :juggle:

True but it’s better than nothing.
And if you know you should be getting 17-19 psi under hard acceleration, but only seeing 10-12 psi, then you definitely know something is wrong.
Rather than just a feeling that it’s down in power and guessing that it’s the turbo.

gibsonsk · **Joined:** Mon Nov 13, 2017 6:36 pm **Posts:** 7

Thanks Guys I will check first thing tomorrow and let you know what I come up with. Off the top of you head do you know that part # for the cheap MAP sensor?

WWDiesel · **Posted:** Tue Dec 18, 2018 11:30 am

gibsonsk wrote:

Thanks Guys I will check first thing tomorrow and let you know what I come up with. Off the top of you head do you know that part # for the cheap MAP sensor?

GM 55206797 :google:

ID Parts and others all can furnish one.
https://www.idparts.com/map-sensor-libe ... -2859.html

gibsonsk · **Joined:** Mon Nov 13, 2017 6:36 pm **Posts:** 7

Wanted it today just got it from advance auto 35 bucks. It will be here at 3:00

gibsonsk · **Joined:** Mon Nov 13, 2017 6:36 pm **Posts:** 7

Well wrong part lol. ordered from JEGGS

gibsonsk · **Joined:** Mon Nov 13, 2017 6:36 pm **Posts:** 7

Ok new MAP sensor no change
must hit pedal two or three times to get the turbo to spool up. then all the power in the world. a lot of black smoke while it is bogging. wondering if I am getting air in fuel changed the filters

WWDiesel · **Posted:** Wed Dec 26, 2018 10:15 pm

gibsonsk wrote:

Ok new MAP sensor no change
must hit pedal two or three times to get the turbo to spool up. then all the power in the world. a lot of black smoke while it is bogging. wondering if I am getting air in fuel changed the filters

What you are describing is a lack of proper boost a.k.a. low turbo boost up when you first hit the go pedal. Black smoke is caused by lack of proper boost!
Now that you have replaced the MAP sensor,
Could be a low vacuum problem to the turbo boost controller located on top of the right hand passenger side finder or turbo boost modulator controller or the turbo boost solenoid.
Need to check these items out and make sure they are all functioning properly.
What you describe is not normally inline with the symptoms experienced with air in fuel issues....

MtnClimber · **Posted:** Sun Dec 30, 2018 10:30 pm

gibsonsk wrote:

Replaced turbo after the rebuild kit failed.

Your turbo lag and heavy black smoke sounds similar to what I'm currently dealing with. What turbo did you install?

Mines the upgraded Sasquatch turbo with the High-Flow Billet Compressor Wheel. I've a.so replaced the MAP sensor and have bypassed the turbo vacuum modulator which did provide a slight improvement. Currently installing the Weeks Stage 1 FCV/EGR delete kit and going over the CAC hoses looking for any leaks.Also running a GDE Full Torque ECO Tune - Now wondering if I need a more aggressive tune like the GDE Hot Tune or equivalent YETI Tune??

05 liberty crd boost hesitation

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