Diagnosing 034 rough running

[mercedesbenz911]

Hi folks,

My 94 E420 is running rough and has an erratic idle after doing a number of jobs at once, including:

• Replaced ALL crankcase breather hoses on the engine. This required removal of the MAF and ETA...hopefully I didn't mess them up in the process. Date code on the ETA is November 1999.
• Replaced ETA to intake manifold gasket (part of above job)
• Replaced small coolant hoses near thermostat
• Replaced spark plugs (Bosch F8DC4)
• Replaced spark plug wire set (10pc, Beru)

I checked the codes and this is what I got:
Pin 4: No faults
Pin 6: No faults
Pin 7: Code 2, code 3, & code 6
Pin 8: No faults
Pin 16: No faults
Pin 17: Code 18
Pin 30: Code 3, code 4, & code 8

After reading and clearing the above codes, I started the car and recorded the following video:

[video=youtube;zti7sl2oL8Q]https://www.youtube.com/watch?v=zti7sl2oL8Q[/video]

After the above video was recorded, I rechecked the codes and the only one that came back was Pin 30 code 3.

Any ideas about what went awry with my car? Thanks.

 

[gerryvz]

Has your upper wiring harness been changed?

Did you just do the blink codes with the homemade blink code counter?

All the pin 30 codes tell you is that airbag was disconnected. Those should clear easily, so perhaps you didn't clear the code 3 properly.

The pin 17 codes is a crankshaft position sensor code. I'd keep your eye on that, for now.

The pin 7 codes are way too vague to be of much use. You need an HHT scan to provide the correct 3-digit codes, which are much more specific and can pinpoint specific items in that system.

Since you just did all that work, I'm wondering if perhaps you have a vacuum leak.

It's rhythmic, happening in a pattern. Sounds and looks to me as if the computer is trying to compensate for an issue.

You may want to take the car to TGA and have them do an HHT or STAR C3 scan of the car's codes, reset everything, and perhaps do a smoke test if they think there's a vacuum issue. if you're up north of the Beltway, let me know and perhaps we could do something at my house.

Cheers,
Gerry

 

[Johnnybenz500e]

I just had this same problem it was a vacuum hose leak to intake manifold

 

[jhodg5ck]

CPS code shows a LOT...I don't think that's your problem.

Vac leak is mighty high up on my list.

I see no mention of caps and rotors?

Jono

 

[Klink]

CPS code shows a LOT...I don't think that's your problem.

Vac leak is mighty high up on my list.

I see no mention of caps and rotors?

Jono

The crankshaft position sensor code is almost always false.