Hey all,

I have a 94E320T with about 200k.

The CE light is on.

The symptom is a sinusoidal cold idle with about a 2 sec period. The idle bounces between 500 and 1000 rpm when the car is cold. This happens when it is in gear and not in gear. The symptom clears up and idles normally when the climate control decides it is time to run the heater fan.

Additional symptom, every great once in awhile, while driving normally the engine will lose power. If you step on the accel pedal power completely disappears like the fuel is being cut. When you release your foot from the pedal there is an extremely rapid idle fluctuation between 500 and 1000 rpm. Turning the car off and back on cures this symptom.

Car has diagnostic codes...

Emissions- 5,26
Pin 8- None
Pin14- 2,5,11

I am thinking perhaps a faulty throttle actuator? Could a bad OVP relay cause this (the fuse is OK?)

Thanks in advance for all your wisdom.

__________________
Kyle Fitzpatrick
Materials Engineer

1969 300SEL 6.3
1992 300E
1994 E320 Touring

Wow, does everyone think it is the throttle actuator?

I was hoping for something cheaper!

__________________
Kyle Fitzpatrick
Materials Engineer

1969 300SEL 6.3
1992 300E
1994 E320 Touring

For those of us who are too absent minded, can you post the meaning of the various codes?

OVP is not the culprit. The OVP powers the ECU, and the ECU controls everything on the engine. If the OVP fails, the engine doesn't run.

The throttle actuator seems unlikely to me. I don't see how idle quality would be affected by cold vs. warm engine if there are problems with the throttle actuator.

I had the opposite problem with this engine - lumpy idle when warm. It turned out to be the O2 sensor. The engine ran fine when in open loop - before the O2 sensor was being read. Once the ECU switched to closed loop, then the bad idle began.

How long after a cold start does it run smoothly, before the lumpy idle begins - 1 minute? 5 minutes?

Typically, a 'bouncing' idle is caused by a vacuum leak. Check out all the vacuum connections.

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.