92 190E Poor idle
 

1992 MB 190E 2.3 L

I have a 1992 190E that shakes at an idle. When I'm driving
down the road the car is fine. But stopped and idling I can
feel the car shake. Off idle it's OK. The head gasket was
replaced before I got the car. Below is a list of the things
I've checked. Does anyone know what the valve timing is supposed
to be? The exhaust valve closing before TDC seems wrong to me?

Engine mounts: OK

Compression: All 160 psi

Cylinder balance: even

Ignition
spark: OK
wires, cap, rotor & timing
adjust timing: 0 deg
replace plugs: Bosche platinum

Fuel System
fuel sample: OK
cold start valve: OK (line disconnected)
system pressure: 80 psi
lower chamber pressure: 74 psi (raises to 80 on decel)
regulator current: 20 ma @ start up; + or - 1 @ warm idle
temp sensor: 2.200 ohm @ 65 F; 300 ohm @ 170 F
throttle switches: OK
air meter: clean & free
air meter position sensor: OK
vacuum leaks: none
decel switch: OK
inspect injector spray: streams
replace 4 injectors and seals
remove throttle body and clean

EGR system: valve OK; vacuum switch broken
replace EGR thermal vacuum switch

O2 sensor: low steady reading
replace O2 sensor: varies .2v to .8v

Charcoal canister purge valve: OK

Cam timing: intake opens @ 18 deg BTC
exhaust closed @ 4 deg BTC

Thanks Jim

Copper plugs
 

The car had the copper plugs in it originally
when it was idling poorly. I switched to platinum
plugs after checking the compression and there was
no change. I could put copper back in but I doubt
it will change anything. It's got me stumped!

Thank you Jim

Be sure to let us know if you solve it, some of us 190ers would appreciate it.

Check your idle valve. I had intermittent crappy idle which turned into no idle (unless I kept my foot on the accel). I replaced my Idle Valve and am now back to normal.

Brian16V

If at idle your car shakes, most likely your motor mounts need to be replaced. I had the same problem and once the mounts were replaced, no more shaking at idle

I replaced all motor mounts and idle control valve. Still feel shake.

Can you be more specific about the symptoms?

Does the engine idle at the proper idle speed, and is the speed steady or does it vary?

Does "shake" mean just a vabration or does is literally SHAKE the car?

Is the vibration frequency constant or variable?

The ignition timing @ idle speed is listed on the emission/tuneup decal on the radiator upper support.

Where did you get those valve timing specs? Mercedes valve timing specs are typically quoted at 1 mm lift, so exhaust valve closing BTC and inlet valve opening ATC is typical since the OE cams have little overlap.

Duke