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Slight engine 'bobble' and consistent misfires (P0300 / 302/303)

5K views 12 replies 5 participants last post by  C32JET 
#1 ·
So my 2002 C32 - 138K miles - jet is having some issues.

Couple issues - it idles oddly at stop lights and has for some time. Its just an annoying 'bobble' that should not be there. Have yet to put my finger in exactly what is causing it.

Recently changed the fuel filter. Changed the plugs. Tested the plug wires - all seem good.

I have used seafoam several times and never had any issues. I have used it to clean the engine internally prior to oil change and also probably 5 times or so in the gas tank. I also recently used the 'spray in the throttle body' method a full can of the stuff. Thinking if the injectors were jacked, this might help. Sprayed, let it sit 30 min - then hard run - some white smoke as expected but not tons. Quick burst and then done. Probably went half mile and turned around and completely gone by time back at my garage.

Thinking it could be a couple issues.

1 . Plugs - doubt it - changed them.

2 . Plug Wires - doubt it - tested all of them. Got new ones.

3 . Cats - ?? - not sure. Some say seafoam or other 'additive' cleaners will mess them up. How to test which one?

4 . Vacuum leak - need to research more on DIY method to do this and where to input the smoke....could be this and just not sure where to look. Have tried spraying starting fluid around the engine several times and locations... nothing really stood out.

5 . Injectors - not tested - suspicious this could be the issue - hence the bottles of seafoam... after many foams... still bobbles. Still not sure on if I should pull them. Also not sure how a shop would test them. I called and got an estimate for like 150 bucks. They say they do it on the car. Not sure how that works but must be super easy for that little of money.

6 . Coil packs - not tested. Tested, swapped side to side... P0300/302/303 issue did not move with them.

Video of bobble at idle.


A bit hard to see the bobble. Sounds like a rickety mess in this video, does not usually sound that shaggy today (more on that below). I have commented over the years how clickety the engine has always sounded. The engine bobble at a stop light is enough to bug me, so much so that I put it in neutral on occasion to make it go away. Thinking is a easy fix and research will will the day.

Ticking 1 - 100K Miles..
https://www.youtube.com/edit?o=U&video_id=8Pn90fgbrkw
Ticking 2 - standing beside car
https://www.youtube.com/edit?o=U&video_id=PqRuJoitjJY
Ticking 3 - relatively cold start
https://www.youtube.com/edit?o=U&video_id=iBSx78qJ83w
Ticking 4 - I thought part of the oil filter broke off... have now accepted that this is how it sounds... after much research here on the forum(s)
https://www.youtube.com/edit?o=U&video_id=NYtp738E904
Ticking 5 - oh man... the clicking is brutal in this vid... haven't watched in a long time... 5 years ago.
https://www.youtube.com/edit?o=U&video_id=zJdgN2EGvVM


Fast forward 5 years..

I did pull a bunch of gunk from my plenums. Not sure this is/was the bobble issue. Cleaned them out nicely and still have the bobble.
Still need to check my intercooler. Never wanted to get so far into a project where I could not drive the call for longer than a weekend. I still think the inter cooler has leaked over the years as I have had coolant loss when driving it hard and in hot temperatures. Have not had to add coolant in a long time, probably as I don't drive it as much and in my mind the leak may have sealed itself somehow given all the gunk in the plenums.

Video - Plenum Gunk


Now that you've seen that video, please comment and let me know if this is completely normal - it had 130K miles on it at the time that video was taken. Does all that crap 'confirm' that my super charger is leaking / has leaked... or just that this is what an engine looks like when you pull the plenums after 130K miles having never cleaned them before.

Blinking Check Engine Light - Oct 2017
I get blinking check engine light now at WOT on freeway and have to pull over to reset the car. The engine stutters badly after I kick it and pop the check engine light. I have intentionally done this twice to replicate the problem consistently. Something bad is up. I know this because I researched 'blinking check engine light'. Bad bad, stop, serious engine issue.

So I checked EGR valve
https://www.youtube.com/edit?o=U&video_id=MoNBj5X2L0M

Not sure if this is the issue. After inspection and hitting it with some brake clean, I do not believe this is the issue. I am curious if this is how they should look or if additional testing can be done on this one.

Here are the current codes - P0300 / P0301 / P0302 / P0303 - and some I do not know what to do with... what they are... lately a P0420.


For the "8 Ready" - I have no idea what those are. Not sure how to use the reader thing fully...

Also saw a video of changing the super charger oil. Should I do that? Did not know that you could / should. How many have done that? Stumbled on video on youtube - never seen it brought up here in the forum. Update... I changed the super charger oil.. mine was a bit smelly but nothing terrible. Was an easy thing to do.

I assume the engine is supposed to sound like that. What I would call clickety / shaggy... not super smooth. Most videos I see on the web of AMG super charger engines of 2002 - 2007 sound similar (32s' and 55s really)
 
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#2 ·
Trying again... any ideas on what would consistently cause a P0300 / P0301 / P0302 / P0303. I can pop the CEL at will now with some strong acceleration. I am on the right track thinking its likely a clogged catalytic converter?
Could it be any of the following:
Purge Control Valve?
EGR?
Crankshaft Position Sensor?
Camlobe Separation? What is this exactly? I found a thread where it has happened on the 2002's.
Oxygen Sensor?
Injectors?
Fuel pump?
Rings / Valves?

I feel good that I have ruled out - Plugs / Wires / Air Filter / Coil Packs / Fuel Filter

2002 C32 - 147K miles.

Thanks for your thoughts...
 
#4 ·
Trying again... any ideas on what would consistently cause a P0300 / P0301 / P0302 / P0303. I can pop the CEL at will now with some strong acceleration. I am on the right track thinking its likely a clogged catalytic converter?
Could it be any of the following:
Purge Control Valve?
EGR?
Crankshaft Position Sensor?
Camlobe Separation? What is this exactly? I found a thread where it has happened on the 2002's.
Oxygen Sensor?
Injectors?
Fuel pump?
Rings / Valves?

I feel good that I have ruled out - Plugs / Wires / Air Filter / Coil Packs / Fuel Filter
2002 C32 - 147K miles.

Thanks for your thoughts...


So the culprit of the consistent codes P0300 - P0303 was that the passenger side front catalytic converter has disintegrated and clogged up the rear passenger cat.





Now fixed. Still after the engine 'bobble'.. will report back when I figure it out.
 
#3 ·
Still working on engine bobble... thinking possible fuel pressure regulator. Is this what a fuel pressure should look like? Wondering if my $20 harbor freight gauge is just cheap.. or.. is this 'movement' of the gauge is meaningful in some way. It holds a solid 50 PSI for 10 min or more after a run. Thoughts?

New video of fuel pressure gauge ==>


 
#5 ·
Ok, team since I have been chatting with myself here... might as well continue... the engine bobble turned out to be a funky fuel pressure regulator in the fuel filter. I had bought a new cheap fuel filter while trying to diagnose the CEL and misfires from the bad cat. Someone had commented on my youtube videos - 'DO NOT BUY A CHEAP EBAY FUEL FILTER - GET OEM/Bosch'. So given they are not expensive I got a new Bosch unit and boom, purrs like a kitten now. The bobble is gone. Figured I would share once I figured it out.
 
#6 ·
Thank you very much for following up and posting a solution. The AMG forums in general are not super active, and that's likely because the cars are not common, but the more problems and real solutions that are posted, the better. It's what an owner forum is all about.
 
#8 ·
Yes, I had disconnected it so I could lift up the air filter to hear the clicking better. It still clicks like a monster even today and still drives like a champ.

Also, wanted to post what a well functioning fuel pressure regulator looks like with the pressure gauge on it to complete the loop (aka the before and after). Engine bobble is gone - whew. This is the first crank after replacing the fuel filter with the OEM Bosch unit.
 
#10 ·
One more update team... the engine bobble did come back ever so slightly... I replaced the MAP sensor and the hit it with a few cans of seafoam. I had run across a post pointing to the MAP sensor as the problem and another one at the same time that maybe it could be a clogged injector. I did both at the same time and should not have. I am going to go with the MAP sensor being the real fix as I've put a few can of Seafoam and injector cleaner in before with no resolution to the bobble. Hard to say exactly... so if this is your issue... try one... then the other... and you'll have a better answer than 'not sure which one was the fix'. She really does puurrr now while sitting at a stop light.

I still have a noticeable vibration at around 40 MPH and have done much trouble shooting. I just replaced the center bearing with no improvement. I have had all four tires balanced recently. I checked the parking brake and looked good. I have always wondered if I had the leaking radiator issue causing an issue with the torque converter. That is what I have elected to tackle next. I have the Valeo radiator and the c32Jet does need coolant now and again... so I've pulled the old gem out and awaiting the new Behr to arrive tomorrow. Will pull the trans fluid and redo it a time or two and see what happens.
This has long been an issue and it sounds/feels like a grinding and I cannot tell where its coming from. It may wind up being a rear bearing or possibly even the differential. Fingers crossed on my radiator fix.
 
#11 ·
I am damn glad you are a stick to it gitter dun kinda guy. Most would have blasted out of here due to the lack of participation. I just posted a very similar issue in my clk55 and hope I get a better response lol. After reading your posts, i am starting at fuel filter and press regulator, see how it hoes from there. Plan to have cats deleted completely by next weekend. Thanks for you percerverenc.
 
#12 ·
Looking at the sludge in the plenum ,,,the question I ask is have you ever replaced valve cover gaskets and cleaned and resealed the breather covers ? They are your PCV system and need all hoses and ports to be clean and clear..
Re the vibration ,,if you think it may be trans related ,,have you ever changed the fluid .filter ,connector bushing etc ?
That may help ...
 
#13 ·
Yes, I have replaced the gaskets, cleaned and resealed the breather covers... twice I think. Over the years as I have been chasing the 'bobble' (MAP Sensor fixed it) and working to diagnose the misfires and CEL (was the clogged/disintegrated Catalytic converter) and noticed some oil leaking while pulling plugs, hoses, and stuff.

Update - I now have a new passenger side catalytic converter, new radiator (BEHR) , new front upper and lower control arms (Lemforder), new center bearing. Runs like a CHAMP. Probably will pop on a new super charger bearing (NSK) soon as its been five years or so.

Still chasing the everrrrrr so slight vibration at 40-50 MPH. Yes, could be the transmission as after I ruled out the center bearing I had a slight leak on my transmission pan. So with the new trans pan gasket came two rounds of new trans fluid which were about 500 miles apart. Seemed to improve the vibration a bit.

My new search is for what seems to be a rubbing noise. Can't tell if it is a wheel bearing in the back or where it's coming from. The journey continues...
 
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