E55 Rough Idle- Any thoughts
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2017 Alfa Giulia gone, 2004 e55 amg gone,2014 E550 coupe white,2010 E550 coupe white, 2018 giulia ti
E55 Rough Idle- Any thoughts
Two days ago I developed a slightly rough idle(tremble) , whether cold or warm. in park, drive etc when sitting still. There is a very slight stumble when initially stepping on the gas. Car has full power otherwise and runs like a beast. No check engine light or current codes for missfires. Stored codes for cat efficiency which I have had for about a yr and half off and on.... The car was tuned up a few months back with one step colder plugs, new wires and coils packs Reason being was random missfire codes in extremely cold temps. Check engine light would come on and i would also have a code p1999. Could the cats be causing the idle issue? Bad plugs all of a sudden? Thought about switching out for a replacement set of stock plugs. All vacuum hoses seem to be intact. I am scheduled for a dyno tune next weekend but now need to get this sorted out. Any thoughts?
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Maybe clogged fuel injectors. I had a issue where I didn't have a steady idle, turn out to be a bad crankcase ventilation valve. Honestly do not know!!
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05 E55, 98 CLK320
I have no cats and car runs a bit rough when I first start it. Gonna take it to my trusty mechanic and see what he comes up with. Only codes are for o2 sensors on the cats.
Getting valve covers, wires, and plugs serviced next week, running some techron through it now as well, but I can't drive it much bc one of my tires is in bad bad shape (waiting on new ones to come in tuesday). So i'll let you know if that solves the problem
Getting valve covers, wires, and plugs serviced next week, running some techron through it now as well, but I can't drive it much bc one of my tires is in bad bad shape (waiting on new ones to come in tuesday). So i'll let you know if that solves the problem
Last edited by MACEDON; 04-21-2017 at 01:27 PM.
#5
Two days ago I developed a slightly rough idle(tremble) , whether cold or warm. in park, drive etc when sitting still. There is a very slight stumble when initially stepping on the gas. Car has full power otherwise and runs like a beast. No check engine light or current codes for missfires. Stored codes for cat efficiency which I have had for about a yr and half off and on.... The car was tuned up a few months back with one step colder plugs, new wires and coils packs Reason being was random missfire codes in extremely cold temps. Check engine light would come on and i would also have a code p1999. Could the cats be causing the idle issue? Bad plugs all of a sudden? Thought about switching out for a replacement set of stock plugs. All vacuum hoses seem to be intact. I am scheduled for a dyno tune next weekend but now need to get this sorted out. Any thoughts?
How many miles... I picked my E up with 120k on the clock and the passenger cat was so clogged it just blew in half after about a week of driving. The portion leading down from the exh runner "log" to the cat looked like an upside down funnel :-/ So I could see this as a possibility
Do you have anyway to see Afr to see if you could have fouled the plugs up by running dog rich during driving
Fuel, air, spark... shouldnt be that hard to triage I would think
Check to make sure all your bolts are firmly seated that hold the coil packs in that is how they are grounded
If you do not have a wideband just pull one of the front plugs and inspect if you can
#6
Usually ,long tubes will make a little tuff at idle due to the amount of flow going threw the system.If the car is very shaky and can feel it even when the car is in drive ,check your coils,plugs and wires to make sure it's all ok.At 70k and up i would change all the 02 sensors to be on the safe side and there all reading correct afr mix.
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2017 Alfa Giulia gone, 2004 e55 amg gone,2014 E550 coupe white,2010 E550 coupe white, 2018 giulia ti
Thanks guys. I know have 98k on the odo. I'm going to look into this tomorrow... Was trying to today but had too much to do. Was speaking with one of my techs. Was told there is no pcv valve being that it's
supercharged.. Definitely going to inspect cyl #8 as the missfire got worse early this afternoon while running errands and a fault came up with that particular cyl finally on my scan tool.. I know all wires are tight and intact because I checked before. Perhaps the coil went bad ( even though its fairly new) or the plug cracked? Not sure but will find out soon enough.. Once I cycled the key off and back on it went back to the slight tremble at idle but I don't want to do any damage to the engine so I must handle this tomorrow.
supercharged.. Definitely going to inspect cyl #8 as the missfire got worse early this afternoon while running errands and a fault came up with that particular cyl finally on my scan tool.. I know all wires are tight and intact because I checked before. Perhaps the coil went bad ( even though its fairly new) or the plug cracked? Not sure but will find out soon enough.. Once I cycled the key off and back on it went back to the slight tremble at idle but I don't want to do any damage to the engine so I must handle this tomorrow.
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Update..pulled the plugs first from cyl 8. They were completely fouled out, totally black. I had NGK's one step colder installed in the beginning of March. Took out the remaining plugs.. They ranged from sooty black to brownish and they were all wet.. Went back to the stock NGK's LFR6AIX. Idle is a little smoother. I'd say 93% improved, but not 100%.. What gives?
#11
***Wet in my past was no good and indicated a blown or weeping head gasket. I have a hard time believing both banks blew and are spewing oil... maybe time for a compression test just to be on the safe side***
You are running too rich under load, what AFR do you see at WOT?
What are your IATs after blasting in 3rd and about 5k rpms in 4th?
IATs are prolly skyrocketing causing the ECU to pull timing and you are just dumping loads of fuel fouling it up... it will happen again unless you verify IATs/AFR and isolate the failure
You are running too rich under load, what AFR do you see at WOT?
What are your IATs after blasting in 3rd and about 5k rpms in 4th?
IATs are prolly skyrocketing causing the ECU to pull timing and you are just dumping loads of fuel fouling it up... it will happen again unless you verify IATs/AFR and isolate the failure
Last edited by BoostedAero; 04-24-2017 at 02:02 PM.
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#12
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while you are doing all this replace the fuel dampener. it can get clogged. possible the tune you put in is way off.
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new plugs, wires, coils
98-2010 Mercedes Benz Spark Plug Ignition Wire Set Of 16PCS $102 shipped
1 step colder NGK (2309) LFR7AIX Spark Plug - Pack of 4 $26.65/4
Bosch 00107 Ignition Coil $55
98-2010 Mercedes Benz Spark Plug Ignition Wire Set Of 16PCS $102 shipped
1 step colder NGK (2309) LFR7AIX Spark Plug - Pack of 4 $26.65/4
Bosch 00107 Ignition Coil $55
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05 E55, 98 CLK320
Getting sparkplugs, covers, wires, and flexdiscs done at the shop tomorrow let's see how it turns out.
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with the valve covers and baffles back in the beginning of March.. Just removed the plugs sun and installed factory heat range since the colder ones were all fouled out