Gas Sprinter P0420 code

[lindenengineering]

PLUGS
We all have our preferences .
Mine Nippon Denso.
A lot of issues can be routed back to fuel deposits in the cylinder causing incandesent deposits.
Result:-uncontrolled detonation,of incoming fuel charge
Dennis

 

[Green Maned Lion]

Running 87 on a Mercedes engine is a fast track to tears.

 

[andymason_]

Also, save yourself $600 and replace the plugs yourself. I just did mine this weekend. Just make sure you're using a thin walled socket for the plugs. Make sure you buy the OEM plugs too, don't cheap out on them. You should be changing them every 30k miles OR 3 years.

These gas sprinters seem to have a very delicate fuel system. I would also make the suggestion of running 91 from here on out too.

For sure ordered Mercedes plugs from FCP Euro will be doing it myself. I’ll try running 91 and see what difference it makes.

I also would love to blame the issues on fuel quality, I’m in California and they change the blend for summer too. Could be a factor making things worse for sure.

 

[gas_sprinter]

PLUGS
We all have our preferences .
Mine Nippon Denso.
A lot of issues can be routed back to fuel deposits in the cylinder causing incandesent deposits.
Result:-uncontrolled detonation,of incoming fuel charge
Dennis

@lindenengineering
Dennis, you just answered to my question in another post.

 

[430 hp 70]

My P0420 was diagnosed under warranty one time as the 02 sensors and another as 2 bad coils. It never ran rough. Same code at 110k and I changed all 4 coils and plugs again.

 

[andymason_]

For those interested, the plugs from my recent change, cylinder 1 on the left to 4 on the right. 3 and 4 looking worse for wear than 1 & 2.

And all my coils were orange on the end, is that normal?

 

[tinrobot]

Your plugs look fine, but your coils shouldn't look like that.

 

[tinrobot]

Now I'm wondering if your plugs are sitting in oil. If so then it could be a valve cover gasket / spark plug tube seal leak.

This could cause misfires.

 

[Maslin]

Plugs look normally worn. The coils always look like that.

All looks normal to me.

 

[430 hp 70]

Well, my p0420 is back only a few days after posting on this thread..... I had 2 coils replaced at 87k with a misfire, up and down stream 02 sensors at 93k and then replaced all 4 coils when I did the plugs again at 110k.

Other than the misfire at 87k where it ran rough at startup for a few seconds and threw the red cel, it's been smooth and gas mileage hasn't changed.

 

[andymason_]

That sucks! Any thoughts on what it could be?

I did a 4 hour drive up and down to big bear with the new plugs, no code back yet. Drove great and gas mileage was better than before.