Intermittent stop - start jerking

[afnan]

I have an eco diesel 2013 GC. I have a very strange problem which two dealerships are unable to diagnose and resolve. When car moves from stop to start it intermittently jerks around 1000-1300 RPM. So far I have spent 400$ in diagnosis without any outcome. The dealer was able to see the problem and said since there is no DTC they don't know where to start.

My findings are as follow:

1. If I disconnect the EGR Valve (attached to EGR Cooler) these symptoms do not happen
2. I have tried performing EGR Valve actuation test but fails
3. I purchased New Mopar EGR Valve and tried to perform the same EGR actuation test (without installing it on the cooler) it fails for that as well. This means that its not the EGR

What my thoughts are now
I noticed that at Idle and low speeds the EGR valve does open. If I disconnect the EGR valve it means that it does not open and the air to fuel mixture is perfect and as soon as the EGR valve opens the engine does not like it. This is seconded by the fact that when RPM goes to 1400 or so the EGR valve closes and the car comes back to life.

So, if its not EGR valve the problem is somewhere with EGR gasses mixing in and maybe O2 is lazy? What should be my next thing to do to find the problem?

[OLMATE]

Originally Posted by afnan

So far I have spent 400$ in diagnosis without any outcome. The dealer was able to see the problem and said since there is no DTC they don't know where to start.

Text Book Mechanics !!! If its not on paper they got no bloody idea

Stick your head up under the dash and check the connecting plug on the ETC (Electronic Throttle Control), then check plug for firm fitting/ corrosion on the throttle body, remove the MAF sensor and give it a good clean if its covered in soot,
If I were you, you need to do a system of elimination before pouring money on non essentials.

[afnan]

Originally Posted by OLMATE

Text Book Mechanics !!! If its not on paper they got no bloody idea

Stick your head up under the dash and check the connecting plug on the ETC (Electronic Throttle Control), then check plug for firm fitting/ corrosion on the throttle body, remove the MAF sensor and give it a good clean if its covered in soot,
If I were you, you need to do a system of elimination before pouring money on non essentials.

I can see throttle smoothly increasing while pressing in the scan tool. I did elimination by un plugging the EGR and the car ran perfectly. I said WhOO got the culprit.

I will clean the Map and check

[afnan]

Originally Posted by Farwest

And the reason finding a GOOD mechanic is very important....NEVER a Dealership....sorry you werent informed...once again....give All Grand Cherokee in Springvale VIC a call with all the details you have....he may have the answer over the phone....if you live in Vic...book it in with him

We don't have many qualified mechs in Sunshine Coast QLD.

[afnan]

Originally Posted by OLMATE

Text Book Mechanics !!! If its not on paper they got no bloody idea

Stick your head up under the dash and check the connecting plug on the ETC (Electronic Throttle Control), then check plug for firm fitting/ corrosion on the throttle body, remove the MAF sensor and give it a good clean if its covered in soot,
If I were you, you need to do a system of elimination before pouring money on non essentials.

By the way, I noticed that when car is on Ignition, the electronic throttle constantly whine like it was crying- is that normal?

[afnan]

Good guess with MAP. I did remove and clean the map. It had black gunk all over it and I noticed that it was also covered in oil. I am not sure if the Oring is leaking or not but it was not 100% dry from the outside and was oil on the circumference of the connector NOT in the connector.
After the MAP clean it definitely has smoother idle and revs smoothly through. I will find out more when I take it from daily drive tomorrwo

Originally Posted by OLMATE

Text Book Mechanics !!! If its not on paper they got no bloody idea

Stick your head up under the dash and check the connecting plug on the ETC (Electronic Throttle Control), then check plug for firm fitting/ corrosion on the throttle body, remove the MAF sensor and give it a good clean if its covered in soot,
If I were you, you need to do a system of elimination before pouring money on non essentials.

[drover]

If your MAP looked like this it could be the reason, the black is soot from your EGR and the wet is oil coming from the stupid PCV set up.........