benznewcomer

Hello, I was hoping someone can assist me on what might be wrong on my vehicle. When driving home i saw a flashing and then solid check engine light and soon there after there was smoke coming out from the exhaust with limited power....when the vehicle was idle there would be significant vibration and shaking, as if there were multiple cylinder misfires....I was able to slowly drive home.

Upon trying to start up the vehicle, it would crank but not start. Upon trying a 2nd time a shortwhile later the vehicle cranked and started but there was a significant and consistent stream of smoke coming out from the exhaust with the smell of gasoline.

Upon using a basic code reader, i see the following codes:
P0300 random/multiple cylinder misfire detected
P0301 Cylinder 1 misfire detected
P0302 Cylinder 2 misfire detected
P0303 Cylinder 3 misfire detected
P0304 Cylinder 4 misfire detected
P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1) (This fault shows as a PENDING fault rather than a CURRENT fault)

Given that there are multiple cylinder misfires i am thinking it is not a coil or spark plug issue but rather a O2 sensor that has failed?

Any thoughts or assistance regarding this would be appreciated thank you.

machild

No idea what model car you have. You know that you have a number of firing issues/dead cylinders and an O2 senosr seems to be dead. Unless you intend to do the repairs yourself, I would suggest having the car towed to your favortie tech. Do not start the engine again!

benznewcomer

My car model is a 2003 E55. Has anyone encountered these codes before together? Would a faulty o2 sensor cause those specific cylinder misfires? I will look at towing the car

machild

A bad O2 sensor on its own will not cause misfiring. There is more going on than just a bad O2 sensor. All the cylinders (1-4) on the right side of the engine are misfiring. Something significant is happening on that side of the engine.

UncleBenz55

Do you still have the OEM pre cats?

benznewcomer

hi there i am not sure if they are OEM as there were few owners before me....do you think it might be a serious issue? i will tow vehicle on friday to mechanic

UncleBenz55

If your catalytic converters are dissolving it can be a very serious issue

benznewcomer

would those codes above show up for a catalytic converter failure? or an O2 sensor failure? from reading through this forum it seems when there are multiple cylinder misfires on the same bank its one of those issues

UncleBenz55

yeah if they dismantle and clog up the bank, it can cause those error codes

jmb614

It certainly is possible that a dead or really lazy O2 sensor can cause the misfiring. From what I have experienced, if the ecu isn't getting a signal or is getting a lazy signal, it may revert to a fueling map that is rich, as without the primary O2 providing its data, the ecu reverts to a failsafe. Usually when this happens, due to the rich mixture, black sooty smoke and misfiring can occur.

Odd story, the mech that was working on my exhaust reinstalled the O2 sensor harnesses with dielectric grease. Shouldn't be an issue right? Right at start up the car starts sputtering and running pig rich. Looked at the dashdaq, saw that the sensors were really slow, shut the car off. Disconnected and cleaned out the dielectric grease and used contact cleaner. Restarted it and it was perfectly idling. Never to show the problem again.

Hopefully you get lucky enough to have it be the sensor and/or its wiring.

Boraxo

I am having the same problem on my GLS 450. Check engine light is on (useless, because that covers numerous issues), the whole car shakes at startup and idle, and I get very little power when I floor the accelerator off a red light. But no smoke and no problem starting. In the old days I would have popped the hood and maybe fiddled with the carburator, but that's not possible anymore.

I do not have a scanner but I suspect the cylinders are misfiring The car only has 60k so hopefully this is covered under the extended warranty I purchased from MBZ.

machild

A proper fail safe fuel map should not cause these issues. A bit richer yes, but belching out unburnt fuel should not be part of it.

benznewcomer

Hey so mechanic said it was due to spark plug or coil as when they replaced spark plugs and coils it the check engine light went away and didn't smoke. They replaced all spark plug and coils did they need to do that or just target the ones that caused the issue? I was seeing codes for cylinder 1 2 3 4 so maybe there were multiple misfires

benznewcomer

To add to that it's a 2003 with 100,000km and I hadn't changed spark plugs or coils since I got vehicle at 45000 km

machild

From what you have reported it doesn't seem that they needed to do more than the coil(s) that was bad. Did they replace all for the entire engine or the one bank - four cylinders?