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wolfgang36
Member
Date registered: May 2009
Location: Memphis, TN, USA
Vehicle(s): 1999 G500, 2009 e350
Posts: 44
| Re: G500 Terrible misfire, flashing CEL
Thanks guys!
I appreciate the thoughts and feedback. I replaced the MAF and will keep the original. After the change the issue startup issue continues. I am going to swap out the K40 with my spare and see if that changes anything.
ODBII is only providing random misfire codes when it occurs. One had suggested that perhaps it could be timing chain or tensioners. Would they need replacement at 150K? Would that explain why the startup issue occurs when cold and gets better after the oil pressure rises? Seems to run well at all other speeds and oil is changed at every 7,500 miles with synthetic. I tried the high mileage 10W 30 on the last change to see if it helped with a minor leak. Could that change in viscosity affect the tensioners on startup?
Thanks again for your thoughts.
John
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| Re: G500 Terrible misfire, flashing CEL
wolfgang36 - 2/8/2018 5:45 PM
Thanks guys!
I appreciate the thoughts and feedback. I replaced the MAF and will keep the original. After the change the issue startup issue continues. I am going to swap out the K40 with my spare and see if that changes anything.
ODBII is only providing random misfire codes when it occurs.
John
John,
I have found any readings from the OBDII plug on my 2000 G500 to be pretty much useless. If you have a Europa Int'l G500, the OBDII circuits were added during Federalization to meet US requirements, and they only do minimal posting. To get a real measure of what's happening on your truck you need a STAR diagnosis connected to the large round multi-pin plug in the engine compartment. |
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wolfgang36
Member
Date registered: May 2009
Location: Memphis, TN, USA
Vehicle(s): 1999 G500, 2009 e350
Posts: 44
| Re: G500 Terrible misfire, flashing CEL
Dutch,
I will be taking it in to the local MB dealer to connect it to the star diag. after I spend some more time chasing down the wiring grounds. After changing the various parts, and keeping the old ones as future replacements, the symptoms have reduced significantly. Odd really as the last part I replaced was a failed door lock actuator. Perhaps there is a poor ground and/or bad connecting sending voltage or loss of grounding for my ecu.
Some other electrical gremlins that have occurred but don't occur consistently...
Right turn signal failure - I can hear the clicking of the relay, but no lights.
Fuel gauge, temperature and tachometer in gauge cluster - delayed reading at start
I will of course report back on progress, however this is one gremlin that remains elusive thus far.
John
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JCH4
Regular
Date registered: Jun 2010
Location: Charleston, SC
Vehicle(s): 2003 G500, LR 1972 IIA, LR 1962 IIA, Husqvarna 350
Posts: 99
| RE: G500 Terrible misfire, flashing CEL
I am having this same problem on my 2003 G500. No question it is worse in rain or humid/wet weather. |
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wolfgang36
Member
Date registered: May 2009
Location: Memphis, TN, USA
Vehicle(s): 1999 G500, 2009 e350
Posts: 44
| RE: G500 Terrible misfire, flashing CEL
Update on progress...
After removing the spark plugs to investigate further, the plugs in cyl 7 were wet. I removed the fuel injectors and noticed that #7 was leaking and was wet, so I purchased some reconditioned injectors and replaced all 8. Big improvement in engine function and throttle response, however the starting issue remained.
After driving and living with the rough start idle issue for the past month, it has diminished in frequency and intensity. The idle is still slightly rough, when cold, but smooths out as the engine warms and runs. I will be checking the o2 sensor on that bank. I am imagining that leaking raw fuel into the combustion chamber hasn't been good for the sensor or cat. I will continue to investigate and report back.
Thank you Dutch and others for your suggestions.
John |
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wolfgang36
Member
Date registered: May 2009
Location: Memphis, TN, USA
Vehicle(s): 1999 G500, 2009 e350
Posts: 44
| RE: G500 Terrible misfire, flashing CEL
Photo of the leaking injector...
 (IMG_9495.jpg)
Attachments
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 IMG_9495.jpg (84KB - 0 downloads)
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NHDave
Extreme Veteran
Date registered: Dec 2013
Location: Seacoast NH.
Vehicle(s): 2004 AMG
Posts: 464
| Re: G500 Terrible misfire, flashing CEL
Interesting find. I too have a slight roughness with the idle during cold starting and sitting at a stop light all warmed up. I may have the same issue, leaky injector!
There are times I start the car after sitting "warm" for an hour or so, and the engine instantly revs to near 2K rpm for a split second. Always thought..a leak in the vac lines but didn't consider injectors.
Time for more piper payments and bloody knuckle scraping I guess!
Cheers all! |
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