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Stan, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3526
Experience:  Technical support engineer
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SL(###) ###-####150k miles - runs perfectly mins then seems

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SL(###) ###-####150k miles - runs perfectly for 2 mins then seems to go to safe mode. at local garage they checked and cleaned injectors, had ECU's sent to expert and checked ok, Exhaust and CAT checked ok.
Only some injectors are firing when problem occurs and each time it's different injectors.
Took to mercedes dealer Doncaster and they coudn't find problem.
Please help been 12 months and many experts!!!! and all baffled.
kind regards
What do you mean by safe mode?
Is the engine misfiring?

Are there any fault codes detected by engine control unit?

Best Regards,
Customer: replied 2 years ago.

Hello Stan

Yes the engine is badly miss firing. switch off and leave it a bit start up and runs perfectly for about 2 mins and then starts miss firing . At Merc

no codes and they said no fault indicated. Merc wanted to strip and clean the injectors and fuel link but that had already been done.

Obviously when it warms up the problem kicks in.



Hello Graham,

One thing to try is to disconnect the mass airflow sensor and see if engine runs better without it on a emergency substitute value. When this sensor is giving incorrect reading, the mixture can become very lean and cause misfire.
Also, i suggest to connect a booster cable to the engine clean metal part and to battery's negative post. Poor engine ground strap can cause very abnormal issues.
Do not hesitate to get back to me after trying this, will do my best to help.
Best Regards,
Customer: replied 2 years ago.

Hi Stan

Thanks I'll try that. Will be Friday. At transport research laboratory TRL

tomorrow. I had the idea and developed the wire rope crash barrier for UK highways with the HA now Highways England and TRL.

best regards


Wish you a productive day at the lab, hope that with your help the highways will get safer.

Just get back to me at your convenience.

Cheers Stan
Stan and other Mercedes Specialists are ready to help you
Customer: replied 2 years ago.

Hi Stan

you''re in America. Took 10 years working with FHWA to get approval in the States - now all over the State Turnpikes and Freeways. Manufacture in Oklahoma City.


Graham (Scottish)