More W126 Economy

[Oliverp]

Hello again,

The W126 300SE has 141,000 miles. As I explained in my last message, I'm trying to get better economy.
Are there any particular parts that if replaced would better economy?
I was thinking maybe the distributor and rotor, and maybe some filters or something.

Thanks for any help

The engine, definitely. Putting a diesel in there would bring the consumption way down.

Seriously, though, there are a few things which will help. A dirty air filter and infrequent oil changes will result in slightly increased fuel consumption (the filter because of constricted air flow and the oil because of diminished lubricating capability - pretty minor effect, admittedly). Problems with the ignition system can result in incomplete combustion which will result in reduced fuel economy. A defective or worn-out oxygen sensor will send a "lean" reading to the fuel injection control system, resulting in an unnecessarily rich mixture. Underinflated tires will reduce fuel economy. Finally, but most significantly, driving habits are a major factor, so watch your economy gauge!

All that said, don't start replacing parts unless you know that they're defective or worn out; you'll spend a lot of money for little or no return in fuel cost savings. The MB gas engines (particularly when mounted in a car like the S-Class) do not offer particularly outstanding fuel economy, and most require premium fuel, so if your fuel costs are giving you heartburn, then you maybe should consider another alternative; the diesels are much more efficient.

If the clatter and smoke of a diesel are a turn off, there may be some consolation in the fact that gas prices are slowly coming back down - for the moment (at least where I am).

[ymsin]

Clean plugs, air filter, oil and oil filter change when required - no hard driving, good MICHELLIN tyres at recommended pressure, and above all ... right engine tuning for fuel/air mixture.

You'd be fine.

Glad to have you back in our MB fold, Oliver.

[sixto]

A couple of tire shop guys told me to run closer to the maximum pressure stated on the tire than the recommended pressure stated on the filler cap. They set my tires at 40psi. The Bridgestone tires that came on my car as so bad that increasing the pressure didn't hurt the ride. The car feels a lot lighter.

My daily round trip commute is 30 miles and takes 50 minutes. I get about 17mpg. If I can throw in some time cruising at 75-80mph, I get about 19mpg.

When better fuel economy becomes more important than sheer mass, I'll trade my car for an LS400. Despite a bigger and more powerful engine, they routinely get 20mpg or better with barely a thought.

Regards,
Sixto
91 300SE

[ymsin]

40psi?

Wow - thats really blowing it. The ride would be quite bumpy and noisy wouldn't it?

The highest I ever inflated was 36 psi.

[sixto]

If you ever have the misfortune of riding on Bridgestone Eager tires, the higher the pressure, the less noisy they are. They're rated at 44psi and 40 has not been a problem.

I have regular duty Bilsteins and the ride at 40psi is not close to objectionable.

Sixto