Engine knock-brought it to the dealer today

[zxd9]

Quick update here: I took the truck to another dealer because I knew something was wrong, and they called me 3 hours after dropping it to notify me there was a rocker/lifter failure and that parts were already ordered.

So the question is: Did they not want to work on it or are the inept at their job? Hmmm....

Guess it pays to get a 2nd opinion.

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[1rider]

So the question is: Did they not want to work on it or are the inept at their job? Hmmm....

Guess it pays to get a 2nd opinion.

Given that the service manager first called me three times, saying it was a big job, and ultimately saying everything was fine leads me to believe they didn't even try.

 

[1rider]

Picked up my truck today; they replaced 6 rockers, lifters, and one cam.

 

[zxd9]

Well....back in the shop today after cam shaft replacement on 3/5. Check engine light came on with the following codes:

P000A - 'A' Camshaft position slow response Bank 1
P0300 - Random/Multiple Cylinder Misfire Detected

Wonder how long this is going to take to figure out.

 

[Lost1wing]

Well....back in the shop today after cam shaft replacement on 3/5. Check engine light came on with the following codes:

P000A - 'A' Camshaft position slow response Bank 1
P0300 - Random/Multiple Cylinder Misfire Detected

Wonder how long this is going to take to figure out.

Every tech has to do their first cam, lifter replacement. You got that guy it seems. They will put little Jimmy's mentor on it now.
Sorry you have to go through this.

 

[tnjarhead]

Every tech has to do their first cam, lifter replacement. You got that guy it seems. They will put little Jimmy's mentor on it now.
Sorry you have to go through this.

Excuses are like ASSHOLES

 

[Stan H]

Well....back in the shop today after cam shaft replacement on 3/5. Check engine light came on with the following codes:

P000A - 'A' Camshaft position slow response Bank 1
P0300 - Random/Multiple Cylinder Misfire Detected

Wonder how long this is going to take to figure out.

Camshaft position sensor is my guess sensor on bank 1 took me 5 minutes to change . If thats what it is.

 

[Lost1wing]

Excuses are like ASSHOLES

The saying is " Opinions are like assholes". Sorry if I offended you. A seasoned tech would have done the job and checked his work. That obviously didn't happen. My "opinion" is that the tech rushed through a job that he wasn't familiar with. That dealership even stated that it was a big job for them.

 

[Stan H]

Excuses are like ASSHOLES

They are always behind you ??

 

[zxd9]

Today's update: Adjusted cam position sensor and got rid of one fault. the P0300 is still occurring but they have been unable to determine which cylinder(s) it's happening on. And we wait.....

 

[Stan H]

Here are some causes which can trigger the P0300 error code.

Damaged spark plugs
Damaged Ignition coil
Faulty injectors
Vacuum leak
Malfunction of the oxygen sensor
Burnt exhaust or intake valve
Defective catalytic converter
A defective throttle position sensor
Faulty PCM
Leakage of the head gasket

The misfire of an engine cylinder causes the engine speed to fluctuate. If this fluctuation increases, it affects the crankshaft position sensor, and the engine management module (ECM) can detect that one of the cylinders is misfiring. It will then store the p300 code

 

[ShadowsPapa]

Here are some causes which can trigger the P0300 error code.

Damaged spark plugs
Damaged Ignition coil
Faulty injectors
Vacuum leak
Malfunction of the oxygen sensor
Burnt exhaust or intake valve
Defective catalytic converter
A defective throttle position sensor
Faulty PCM
Leakage of the head gasket

The misfire of an engine cylinder causes the engine speed to fluctuate. If this fluctuation increases, it affects the crankshaft position sensor, and the engine management module (ECM) can detect that one of the cylinders is misfiring. It will then store the p300 code

Or not store the code.
if it's transient, it may well not store it.

add to the possible misfire issue - CCDIFF isn't learned. This normally causes a misfire after a hot restart, not a cold start. The fix is to force a CCDIFF relearn .Check the PCM for values there - if there are no values, there's a problem.

Misfire on a Grand Cherokee 3.6 we had was due to spark plugs, but code was not stored, and MIL wasn't set.
Similar for my JT's hot restart misfire. MIL sometimes, not other times, and at times it would flash on and off.
I believe the relearn should be done any time cam related parts - cam, timing chain, etc. - are replaced.

 

[Stan H]

Or not store the code.
if it's transient, it may well not store it.

add to the possible misfire issue - CCDIFF isn't learned. This normally causes a misfire after a hot restart, not a cold start. The fix is to force a CCDIFF relearn .Check the PCM for values there - if there are no values, there's a problem.

Misfire on a Grand Cherokee 3.6 we had was due to spark plugs, but code was not stored, and MIL wasn't set.
Similar for my JT's hot restart misfire. MIL sometimes, not other times, and at times it would flash on and off.
I believe the relearn should be done any time cam related parts - cam, timing chain, etc. - are replaced.

What I am figuring is if the sparkplug or injector were malfunctioning enough then He might possibly get a P0302 code or similar instead of a general all encompassing code like P0300 . With the oxygen sensor being one of the possible causes , it's literally an 82.00 part for the bank 1 upstream master O2 sensor .
I personally had a code 2 months ago "failure to complete a closed loop fuel circuit" now My code was rather Ambiguous also encompassing the crank sensor, master bank 1 O2 , the MAP sensor,( which was very dirty), the PCV valve, and water Temp sensor.
Sooooo.... i looked up the price for all of them weighed that against a computer hook up , labor and parts and figured my cheapest option was to buy and install them all. I did and now the code is gone. Barring the internal things like burnt valve as one of the possibilities, if it was me I would start replacing parts and see if something sticks.
I know it isn't the exact way but even at that for longevity purposes everything may be renewed on that bank . Just saying. What ya think . ? Now if He wants to take it to a garage and have it done fine and dandy .

 

[Stan H]

Another thing is a burnt valve can be diagnosed with a compression tool. I happen to have one . That one on the list not every person would have a compression tester gauge .

 

[ShadowsPapa]

Another thing is a burnt valve can be diagnosed with a compression tool. I happen to have one . That one on the list not every person would have a compression tester gauge .

Burned valve will be very rare in these.
The causes have been all but eliminated. It used to be not uncommon in the days before positive valve seals, better guide tolerances (tighter guides) and greater oil consumption that was common in engines of the past.

You can also often tell by exhaust sound, and on a slowly idling engine, by using a dollar bill, or tissue, at the end of the tail pipe. A faulty exhaust valve - either by burning or by being held up by carbon, will allow reverse flow in the exhaust system and pull the tissue or dollar bill TOWARD the pipe every so often

He might possibly get a P0302 code or similar instead of a general all encompassing code like P0300 . With the oxygen sensor being one of the possible causes

Misfires on one bank caused by "something in common between the 3 cylinders) will still usually cause a 0300 because a sensor will impact all cylinders of that bank.
A code for a single cylinder will usually mean something specific to that cylinder, not something shared.

Here's your "compression tester". (mine is showing age at 50 years!)
There are so many means of diagnosing a misfire - I usually only use this to nail down other issues, like rings, piston issues and so on.

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