I used to work in a factory that made gas aditives-we run chevon,stp,etc just by changing bottles and labels also some high end cars had their aditives mixed there .
AS for bad fuel make sure u change fuel filter after bad bunch of fuel-pump failers ussually caused by a plugged filter putting extra back pressure on the pump.
People that use their merc. in cold climmits should add a can of heat also during the winter time to burn the water out, normal fuel aditives do nothing for water.
Is lots of bad fuel station operators that add water to ethenol in gas just cause they can.
Best to bye your fuel at same station if can, myself never got bad fuel at a shell station but thats just me.
WHAT ABOUT SPARK PLUGS. IF WEATHER MAKES A DIFFERENCE THAN SPARKS ALSO?
NGK Canada published a TSB in 2006 in which they state that due to ethanol being introduced in gas, drivers have been reporting these symptoms:
1. Reduced gas mileage
2. CEL light, code showing lean condition
They recommend the following to remedy both issues:
A. One step colder
B. Narrower gap by 0.010", not to go below 0.035"
For my vehicle, I've done the following:
- One step colder
- Narrower gap by 0.004" (factory spec for my M119.982 is 0.032")
So far, after two tanks of gas (several hundred miles), my mileage seems to be better, the insulator is still too white for my liking (indicating still a lean condition), and the ground electrode reading shows color change at the turn of the elbow (but closer to the ring, which indicates it's still slightly hot).
Btw, the spark plug gap is a debatable topic. This is my take:
Reduction of the gap is necessary in E10 gas for the reason that ethanol--while it is detonation-resistant--is more susceptible to pre-ignition at higher compressions. My M119 having 11:1 compression ratio and achieving greater than 100 KPa, the possibility of pre-ignition with ethanol is greater. (Maybe this is why Mercedes says their knock sensors can't handle lower octane gas?) The possibility becomes even greater knowing that gas stations sometimes goof up and pour the wrong octane gas in their underground tanks.
However, my M119 uses non-resistor plugs, and the coil connector provides 2K Ohms. Narrower gap effectively decreases resistance. This may cause potential electronic interference with the ignition system. When reducing the gap, using resistor plugs (which will have 5K Ohms) might be a good idea.
ALSO THOSE WITH 2002 AMG AND MERCEDES PRIOR SHOULD BE HAVING PROBLEMS ESPECIALLY YOU RARELY USE THE CAR, ANYWHERE FROM 30-90 DAYS. COULD BE SOONER DEPENDING ON CONCENTRATION.
NGK technical bulletin: No. NGKSP-0506-3 (from may 2006)
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