300e 0-60 problems - PeachParts Mercedes-Benz Forum

#1 10-21-2002, 11:05 PM

Hey , Been along time since i was talking on this forum!!!!!!!!!! anyways!!!!!!

Recently i have test my 141k mile 1986 300E and the 0-60 was a avrg of high 8's to med 9's.. just wondering wut you think should be done to TUNE IT up to make it back to stock form? around 8 would make me happy! ! ! any ideas? spark plugs? distrub cap?! thx!!!!!!!!!!!!!!!!

JAshburne · #2 10-22-2002, 01:46 AM

At 141K miles, there may be enough wear on the rings and valves to cause that slight deterioration in performance. Wasn't 0-60 time when new right around 8.0 sec.? I'm assuming that your plugs, wires and fuel system are all in good shape.

You might want to perform a compression and leakdown test to get an idea of the condition of valves/rings etc.. Even though the engine is pretty robust for high mileage as long as the oil is changed regularly (except for the valve guide seal problems that affected the 86-87 model years), there is likely to have been some wear in those parts. A "tune-up" won't correct for that.

pentoman · #3 10-22-2002, 07:38 AM

You're running high-octane fuel, (presumably as you removed your resistor). Worth getting a tune up to advance/retard the ignition as necessary for the fuel you're running.. the car has no knock sensor so won't do it itself.

#4 10-22-2002, 08:45 AM

I would like to check the ignition timing on my '86 300E also. I don't have access to the shop manuals, and would like to know the specs. At what setting BTDC should it be at 3000 revs?

#5 10-26-2002, 03:49 PM

leakdown test wuts that? i know wut a compression is and i could do one soon wut should it be for a compression around 150?

#6 10-26-2002, 04:10 PM

Maybe you've just been running the living snot out of it.

#7 10-26-2002, 04:38 PM

i just bought it.

suginami · #8 10-26-2002, 10:58 PM

FWIW, the early 300E's had a 0-60 mph time of 7.5 seconds, and a 1/4 mile of 16.0 seconds.

#9 10-27-2002, 01:43 AM

ya and mine is 9.5 !!!!! anything i could do on my own to help it?

pentoman · #10 10-27-2002, 06:46 AM

Those times they obtain are done in a way that's very heavy on the cars, and would be the best they acheived out of a *lot* of attempts. Don't worry if you can't match it. If you want to know if your car is for some reason down on power, see what your top speed is, and how it compares to the claims/road tests.

psfred · #11 10-27-2002, 01:17 PM

Check the condition of the plug wires, cap, and rotor -- these aren't replaced very often on these cars, and second (or third) owners often baulk at the cost for routine replacement. The cap and rotor on my 88TE were terrible -- the contacts in the cap were almost completely eroded off! There was evidence of arcing all over the plug wires, and the plugs didn't look very good, either.

You cannot adjust the ignition timing, it is programed into the computer and calculated off the crank position sensor.

Best bet is to do a complete tuneup, replace all the rubber vacuum hoses, check and adjust the mixture (and check the O2 sensor operation -- if the O2 sensor is bad, you won't get optimum performance). You will probably need to replace the idle control valve hoses, too -- mine were rock hard and leaking.

Change the oil in the rear end, put in synthetic (less drag), change to synthetic tranny fluid and engine oil, check brakes for drag (another place people cheat on maintenance), check for proper tire size and inflation. If the tires are old, they can aquire excessive rolling resistance, slowing your down.

Last, drive carefully, please -- it's nice to have great acceleration, but remember -- speed kills!

Peter

#12 10-27-2002, 05:37 PM

How do brakes Drag? How should I check for this? How should I fix the problem?

Dan

psfred · #13 10-27-2002, 05:47 PM

Disk brakes retract due to the resilence of the rubber seal for the piston. When this seal gets old or hard from overheating, or gets dirt around it from a torn dust seal, the piston will no longer retract immediately. If it is really stuck, and only goes out, rotor runout won't push it back, either, and the brakes don't completely release.

This usually shows up as jerky stops -- even if you reduce pedal pressure as the car stops, the pressure on the pads doesn't go down fast enough and the car jerks as it stops. Can make the brakes groan or squeal, too, depending upon what is stuck where -- Volvos are really bad at this because they have two pistons side by side in the caliper.

The fix it to replace the piston seal, or the caliper, depending upon condition. All caliper will eventually go bad as the seal won't last forever, but this is on the order of 30 years if the brake fluid is changed. Most cases are from dirty brake fluid (never changed) and attendant corrosion, or, more typcials of Benz, running rotors too thin so the pistons cock in the bores and stick, overheating the calipers, ruining the seals and dust boots.

Parking brake shoes can get stuck, too, or be adjusted too tight, so they don't release.

Dragging brakes will cause poor fuel milage, overheating, and odd braking on slippery surfaces, too.

Peter