Why runs rough when hot
#1
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Join Date: Sep 2020
Location: Southern CA
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500SL 450 SL 230 SL E320
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Help!
My E320 wagon runs great when cold but runs rough and misses after 10 minutes when reaches full temperature.
What are possible casues ?
My E320 wagon runs great when cold but runs rough and misses after 10 minutes when reaches full temperature.
What are possible casues ?
#2
Junior Member
Possible fuel venting issue. When it is doing that, pull in to a gas station and slowly undo the gas cap and see if you have a lot of vacuum. Charcoal canisters can cause this.
#3
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500SL 450 SL 230 SL E320
#4
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Wondering if it's a "simple" vacuum leak. The cold start circuit is dumping more gas to mask the lean effect of an open vacuum sucking more air. When it warms up and the system goes back to less fuel delivery, then you could be going into a lean mixture. Or, like all electrical, something is breaking down electrically as it heats up. Even a coil or plug wire can give this type of issue. (less likely) The Charcoal canister issue if the culprit, will give you a very strong smell of raw gas when parked and a rich mixture from the recovery system won't allow it to idle without hunting for a steady idle RPM.
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This is still OBD I??
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