2007 E550 Sulfur smell
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Joined: Jan 2016
Posts: 162
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From: Rochester NY
07 E550 4M - 11 Audi TT - 99 Expedition EB
2007 E550 Sulfur smell
I've mentioned this issue in another thread I made about correct spark plugs but thought I would start a thread specifically for this issue in the event someone has some other ideas.
I've got a 2007 E550 that currently has about 118k miles on it. It runs great, has good power still and I'm getting 22-23mpg on the highway. On hard acceleration (full throttle for more than a few seconds) I get a pretty strong sulfur (rotten egg) smell coming from the exhaust.
Fuel trims are slightly negative even with E10 93 octane fuel from several different sources over the course of thousands of miles. With 10% ethanol in the fuel, I would expect to see positive 4-5% fuel trims. I'm currently seeing negative 2 or 3% trims (across both sensors) so I'm guessing something is causing a minor rich condition. I'm seeing 12-12.5:1 AFR at full throttle. I'm also seeing catalytic temperatures hitting 1750 degrees Fahrenheit (across both cats) at full throttle. If anyone else with the m273 engine is logging their driving, could you verify your cat temps at full throttle?
Things I've done so far that could be relevant include:
Tehron in fuel tank several times.
B12 Chemtool in fuel tank several times
Top engine cleaning with seafoam via vacuum induction (not a good idea for this car).
All four O2 sensors replaced with Bosch parts.
Maf sensor replaced with Bosch part.
Map sensor replaced with Bosch part.
Air filters replaced with Mann filters. (car came with K&N filters)
Thermostat replaced with new OEM.
Coolant temperature sensor replaced with new OEM.
Full PCV system replaced with OEM parts.
Spark plugs replaced with Bosch plugs.
Plugs re-gapped from .32 to .4 as per the manual. (this might have made smell slightly worse)
At this point, I'm considering doing one or more of the following:
Remove and clean/replace fuel injectors. (Possible leaking injector over fueling Cats?)
Purchase a rather pricey performance tune in hopes of leaning out the fueling at full throttle a bit.
Replace all 4 cats either with 4 new or 2 new and 2 rear deletes. I'm reluctant to do this as it's quite costly and if the problem isn't resolved, the potential over fueling could destroy the new cats as well.
Hoping someone has some advice based on experience, or possibly knows of a recall or ECM update that might solve this. Thanks for reading.
I've got a 2007 E550 that currently has about 118k miles on it. It runs great, has good power still and I'm getting 22-23mpg on the highway. On hard acceleration (full throttle for more than a few seconds) I get a pretty strong sulfur (rotten egg) smell coming from the exhaust.
Fuel trims are slightly negative even with E10 93 octane fuel from several different sources over the course of thousands of miles. With 10% ethanol in the fuel, I would expect to see positive 4-5% fuel trims. I'm currently seeing negative 2 or 3% trims (across both sensors) so I'm guessing something is causing a minor rich condition. I'm seeing 12-12.5:1 AFR at full throttle. I'm also seeing catalytic temperatures hitting 1750 degrees Fahrenheit (across both cats) at full throttle. If anyone else with the m273 engine is logging their driving, could you verify your cat temps at full throttle?
Things I've done so far that could be relevant include:
Tehron in fuel tank several times.
B12 Chemtool in fuel tank several times
Top engine cleaning with seafoam via vacuum induction (not a good idea for this car).
All four O2 sensors replaced with Bosch parts.
Maf sensor replaced with Bosch part.
Map sensor replaced with Bosch part.
Air filters replaced with Mann filters. (car came with K&N filters)
Thermostat replaced with new OEM.
Coolant temperature sensor replaced with new OEM.
Full PCV system replaced with OEM parts.
Spark plugs replaced with Bosch plugs.
Plugs re-gapped from .32 to .4 as per the manual. (this might have made smell slightly worse)
At this point, I'm considering doing one or more of the following:
Remove and clean/replace fuel injectors. (Possible leaking injector over fueling Cats?)
Purchase a rather pricey performance tune in hopes of leaning out the fueling at full throttle a bit.
Replace all 4 cats either with 4 new or 2 new and 2 rear deletes. I'm reluctant to do this as it's quite costly and if the problem isn't resolved, the potential over fueling could destroy the new cats as well.
Hoping someone has some advice based on experience, or possibly knows of a recall or ECM update that might solve this. Thanks for reading.
