[BusterOz]

Update: Engine hunting and vibration seems to start once the car has warmed up.

 

[aleisa_az]

if it was my ride, I would just flush the engine + change engine oil and filter + fuel filter + cleaning the injectors + cleaning the MAF sensor (my self!) + cleaning throttle body (my self!) + replace the engine air filter.

then if non of the above works I would take the catalytic converter off (just for testing)

then if non of the above works that is the time for the mechanic

I remember I had a toyota camry 4cylnder it kept doing that all the time it feels like the engine would die when it was shifted on (D) and I was stopping all what I did was cleaning the throttle body! (the dealer says it was normal)

 

[tripplec]

I am not certain about the Compass but as a long time Jeep owner the Computer does not like a low battery at all and engine management goes south with weird things happening. Having the battery checked and/or if 4 years or more old replace as its end of life anyway with the lugs well cleaned for a 1st rate connection.

Having it scanned for codes take a lot of the guess work out. If no codes then as stated some basic maintenance which is likely long overdue anyway.

 

[aleisa_az]

Update: Engine hunting and vibration seems to start once the car has warmed up.

aha, advice check:
1- MAF sensor: if it is oprating as it should + clean it
2- Throttle body: clean it
3- Catalytic converter off (just for testing)

if no change:
4- replace sparks to factory advised type! Maybe previous owner used wrong once.

 

[BusterOz]

Just had a major service (48,000 km) by a reputable mechanic, still occurs, BUT only once warmed up!

Any other Jeep owner ideas??

 

[aleisa_az]

yes yes yes,, there is a sensor in the throttle body I recall it control the RPM to heat the engine up when you start it SO the RPM is higher than it should Than in normal idling or driving mode! therefore you r noticing this symptoms!

A- Please turn the car ON leave it or drive it until it shows you the same vips then (keeping the engine ON) please disconnect the MAF sensor connector = Any change?
if YES - the MAF is working (go to B)
if NO - the MAF is dead! (replace)

B- Clean the throttle body and it sensors - try it and report please

Stay Cool you have a nice problem well be soon solved

 

[BusterOz]

But there's no vibration or hunting when in Neutral!

 

[aleisa_az]

But there's no vibration or hunting when in Neutral!

because there is no load!

Now when your problem starts and you compass is not moving but the gear is on (D) do you feel the vibration? but when you shift to (N) it is gone and the RPM raised a little?

if yes I totally think your problem is the engine!
Check the EGR valve, To check the EGR, remove the vac line to it and plug it off. If the problems go away the EGR is bad or dirty.

symptoms of what appears to be a stuck EGR valve
Rough idling, hesitation, poor performance, weak vacuum and backfiring all seem to indicated that the EGR valve is at least partially stuck open. Additionally, you can hear what sounds to be exhaust notes coming from the open throttle. Lastly, applying vacuum to the EGR valve has no effect on it.

I remember on time one of my trucks after I installed a new CAI I forget a small hose venting hose caused a lot of hunting especially on high gear oh it was frustrating then after the few checking I noticed it and connect it..

 

[BusterOz]

Maybe the answer, I'll chase up with mechanic!

http://www.wkjeeps.com/misc/Patriot/TSB/tsb_1801708a.pdf

 

[aleisa_az]

Maybe the answer, I'll chase up with mechanic!

http://www.wkjeeps.com/misc/Patriot/TSB/tsb_1801708a.pdf

what is the news??

 

[BusterOz]

:spinning: Booked in next Thursday, Austime, I'll let you know if they find anything

 

[BusterOz]

Okay, my Jeep Service Centre took a look at my 2.4L CVT Compass today and they "cleaned the spark plugs" - not sure what else, but seems to have lessened the shakes and no hunting, plus auto seems to shift smoother with less groaning from under the bonnet. :eyebrows:


Told me to see how it goes and let them know. :wigglesmiley:

Keep you posted!

 

[tripplec]

Okay, my Jeep Service Centre took a look at my 2.4L CVT Compass today and they "cleaned the spark plugs" - not sure what else, but seems to have lessened the shakes and no hunting, plus auto seems to shift smoother with less groaning from under the bonnet. :eyebrows:


Told me to see how it goes and let them know. :wigglesmiley:

Keep you posted!

With the price of them and only 4. Why did they not just replace them. I don't know how many mile you had on them since they were last changed but. If they were that fouled up either very bad gas was used or oil is burning as well build deposits on them. I may happen again in a short while.

 

[BusterOz]

Major service (48,000km) done 2 months ago by reputable service centre (non-Jeep), plugs "replaced" (with non-genuine ones).

Apparently they were blackened when Jeep Service looked at them - yeah, I think I'll get them to replace them with genuine Jeep ones.

Compression test was okay, so no engine oil getting into combustion chamber.

I always run 98 octane fuel.

I am not convinced that isue has gone away - next few days/weeks will tell.

 

[tripplec]

Well black means its not burning completely or hot enough. 98 octane is way to high for the engine. Stick to the spec's the engine is designed for. 87 octane maybe 89 at the most. High octane requires a different fuel programming ignition and mixture ratio.

 

[BusterOz]

Australia only has 3 choices; 91, 95 or 98 - some with 10% ethonol

 

[tripplec]

Well your engine will not be spec's to require anything higher than 91 for sure. Ours are 87 octane and I seriously double the engines are engineered different to handle the higher octane. That far too high of a jump and you're actually damaging the engine and emission sensors by using 98. Look in you owners manual and/or contact your local dealer. Few engines are engineered for more than the regular grade of gas. Those that are tend to be performance engines with high compression. I always say stick to name brand gas station SHELL as an example and stay away from no-name generic named stations.

 

[BusterOz]

Thanks tripplec,

I use only Shell, I'll drop back to 91 Octane or 95 as I don't want to use 10% ethenol, I think 91 only comes with 10% not straight?

See how she goes.

 

[BusterOz]

What Octane fuel should I run?

Did some research:

Australia, like Japan and Europe use a system called RON or Research Octane Number to determine the octane rating of our gasoline, while the USA use a system called AKI or Anti-Knock Index to determine gasoline's octane rating... Apparently, the AKI system is derived from the average of the RON system and another more complicated system referred to as MON or Motor Octane Number... So the methodologies for measuring gasoline's octane rating are different, but share some common elements...
So, with the commonality of RON in mind a good rule of thumb is as follows, multiply the foreign RON Octane rating by 0.95 and you will have the US AKI equivalent.

( RON Octane Rating x 0.95 = AKI Octane Rating )
91 RON Octane x 0.95 = 86.45 AKI Octane (US measure)
95 RON Octane x 0.95 = 90.25 AKI Octane
98 RON Octane x 0.95 = 93.1 AKI Octane
100 RON Octane x 0.95 = 95 AKI Octane

So, I think I'll run 95 RON and see how she goes.

Replace the spark plugs with genuine Jeep ones too!!!

 

[tripplec]

We have ethanol in ours the same 10% while the new engines are designed for it older ones are not. Paying premium dollars for a cheap liquid which gives poorer gas millage and ultimate using more fuel is a rip off to the consumer. If the computer could adjust the timing etc for higher and better quality of gas it would be great. But continuous use of a much higher octane will have negative result since it too far off the spec's of the engine design. Shell has a email forum you could ask them or other specialists. For us going from the default 87 to 89 octane is not huge and more tolerable and may only be 5% ethanol from the advertising but it come at noteworthy cost!!