SOLVED: Uneven idle, hesitating when accelerating, power is down (Faulty CKP)

[little_e]

So I tried to measure duty cycle (while I'm waiting for Star) the old fashion way. First I tried the X11-connector at the left fender (pin 2 and 3), but my multimeter reads zero (set to duty cycle). Then I went to the X11/4-connector (38-pin). Nothing - it reads 0%. Really? Can this be happening? I was measuring through a breakout box (pin 13 and 14). Could it really be that there's some fault somewhere causing this?

Pin 6 code 11 + 17 seems to have cleared up btw.

 

[195910]

Do you have the adaptation values ?

 

[little_e]

How can I read adaption values with a multimeter?

 

[195910]

No, I though you were getting a star diagnosis.

 

[little_e]

Yeah, waiting for it

 

[little_e]

Today I managed to measure the O2 sensor. It starts at around 450 mV (cold engine) and after some time it rises to 895 mV (warm engine, idling). The engine is running too rich, so that can explain the roughness that I'm having at idle. Right?

 

[195910]

Today I managed to measure the O2 sensor. It starts at around 450 mV (cold engine) and after some time it rises to 895 mV (warm engine, idling). The engine is running too rich, so that can explain the roughness that I'm having at idle. Right?

If its stuck rich then the O2 sensor is dead. Its not possible for the car to run rich constantly at such a high value.

 

[little_e]

It's my second O2-sensor after I bought the car. The first was an OEM Mercedes-sensor, at the moment I'm running a Bosch-sensor (not a universal type). Check the list at the start of the thread listing all the parts replaced. I also tried with a different LH ECU. No difference.

 

[195910]

Have you check heater power supply? meaning is the o2 sensor heating up ?

An actual rich condition would be highly unlikely, it would have to be dumping fuel (ECU fault) or a leaky injector(s)

 

[little_e]

We tested with a multimeter that the cables going from the O2 sensor connector in the floor to the ECU connector are not broken.
How else can it be tested?

 

[195910]

We tested with a multimeter that the cables going from the O2 sensor connector in the floor to the ECU connector are not broken.
How else can it be tested?

is the heater cables giving power to heat the sensor? check voltage coming from heater pins.

Although it appears to be giving readings it should be heating up +300C,

 

[little_e]

So can we actually measure the temperature it heats up to? Using an IR temp gauge perhaps?

 

[little_e]

There is voltage there (if I remember correctly). What could be the fault causing the sensor not to heat up?

 

[195910]

There is voltage there (if I remember correctly). What could be the fault causing the sensor not to heat up?

Hmm, If there is 12v in key on position or at idle then the heater should be warming the sensor to +300c.

Do you have a laser thermometer to check how hot the O2 sensor is?

 

[little_e]

Well, I think I have access to an IR-thermometer. That will have to do the trick.

 

[little_e]

As written earlier in the post I cannot read any fault codes from the EZL-module using the blinker method. I got my Star up and running, and it cannot read fault codes from the EZL either. From that I can only assume that the EZL has a fault and it's running in a failsafe mode with a fixed dwell angle, causing the injectors to stay open too long.

A used EZL has been ordered from eBay, and we'll see what happens.

 

[195910]

Unfortunately its the worst option.. but the only one at this stage
If you have access to another car you could try the LH, EGAS and base modules

 

[little_e]

I already tried a different LH module.
I don't have any fault codes in EGAS or BASE, so since there is something obvious wrong with the EZL I will swap that first.

 

[gerryvz]

Failed EZLs have one of two modes of failure:

1) The car will not start at all. Runs on exactly ZERO cylinders.

2) The car will start, but runs on only one bank of cylinders. Runs on only FOUR cylinders, to be exact.

No other documented failure modes. Failure mode 1 is more common. I personally had Mode 2 happen to me. The car idled roughly and ran/sounded like a flat-four Subaru. You could smell the unburnt fuel out the exhaust pipe.

It is possible you are in failure mode 2.

 

[little_e]

It's only at idle the engine doesn't run right. It has small shivers, but as soon as I touch the throttle it goes away. I can't see the engine having full power, and it consumes lots of gas. It might not be the EZL, but the fact that it's impossible to read fault codes from it is not a good thing.

 

[gsxr]

If the engine runs on all cylinders off idle, the EZL may be at least partly OK. If you swap the EZL and still cannot communicate with it (no blink codes, no digital connection via SDS) there may be an issue between the 38-pin connector and the EZL. Thought this was mentioned earlier in the thread but maybe not...

 

[little_e]

If the engine runs on all cylinders off idle, the EZL may be at least partly OK. If you swap the EZL and still cannot communicate with it (no blink codes, no digital connection via SDS) there may be an issue between the 38-pin connector and the EZL. Thought this was mentioned earlier in the thread but maybe not...

Yes, that ls true - but does the Star and the blink method communicate in the same way?

 

[gsxr]

Yes, that ls true - but does the Star and the blink method communicate in the same way?

Yes and no:

Yes, they both use the same wire between the diagnostic connector pin #17 and the EZL itself.

No, they use different methods... analog blink / pulse signal is not the same a digital communication with live data stream.

If something is wrong with the connector or wire, neither method would work, even with a known-good EZL.

 

[little_e]

Well, measuring the cable between pin 17 and the EZL would be easy.

 

[gsxr]

Well, measuring the cable between pin 17 and the EZL would be easy.

Yup. Good place to start.

 

[little_e]

Before replacing the EZL I thought I'd replace the CPK [crank sensor] and CMP [cam sensor] as a precaution.

How the car ran with the CPK I don't know - pictures attached.

 

[195910]

EZL would use CMP if Crank position sensor signal not plausible.

Did it have any effect?

 

[little_e]

Currently we're struggling to get the metal part of the old sensor out. I'm hoping we won't have do drop the transmission
But the engine won't start if the crank sensor is totally dead - right?

 

[little_e]

So - after replacing the crank position sensor lambda regulation is back on track.

The EZL seems to be living a life on its own, at least there is no way to get diagnostic output from it.

 

[Kyiv]

@little_e, was there ever a resolution? Such an abrupt to such an interesting investigation

 

[little_e]

Yes yes, as I wrote - after replacing the CPS CPK [crank sensor] the car is totally fine

 

[Kyiv]

@little_e, thanks. But as far as communication with EZL, nothing, though it's working fine (living the life in it's own) ?

 

[little_e]

@little_e, thanks. But as far as communication with EZL, nothing, though it's working fine (living the life in it's own) ?

I can communicate with it using a proper Mercedes blinker tool (blinker adapter). Maybe the problem is just a combination of china tools and an old car

 

[Phoenix127]

Yes yes, as I wrote - after replacing the CPS CPK [crank sensor] the car is totally fine

I am having the same issue but no error codes for this sensor. I am curious if the sensor is in a position where it might be physically damaged during motor mount replacement when the engine/ transmission is raised. Can it contact the underside of the car?

 

[dionphaneuf]

Interesting - I think I may also have the same sensor issue, and I share @Phoenix127 's concern about motor mounts damaging this. It later had its engine mounts replaced. At times it idles fine, but I have a lot of the symptoms described in the first post.....at times a slightly wonky idle with a shaking engine, hesitation in acceleration at times (I floor it, it 'thinks' briefly, then goes) and also a slightly irregular exhaust, almost like it has an ever so slightly lumpy cam a la some Chevy. No blink codes, haven't checked other modules.

My car had its Crank sensor replaced, 0031532828, in March 09, 12 years and 35k mi ago, albeit by a shop that used TruckTec parts for a Cam Solenoid....Can you described some of the other symptoms @little_e? I also renewed plugs(1mm gap), rotors, caps, insulators recently and have replaced the EGR/Smog pump vacuum bundle which had a small leak somewhere.

 

[gsxr]

The sensor is located at the rear of the engine, and unless the wire is routed VERY wrong, it should not be possible for the wire to be damaged during engine mount R&R.

I recently had a car with similar symptoms as @little_e, very intermittent, most other parts replaced with no improvement. The symptoms can be pretty severe, definitely more than a wonky idle. More like the car would become undrivable for a short period of time. Main clue was the exhaust would reek when the problem occurred, and lambda live data was way off from normal, despite zero fault codes.

@dionphaneuf, check the sensor connector at the EZL and see if there is any part number of mfr referenced. And check the invoice from the shop to see if they mention a brand name, or what the cost was.

 

[dionphaneuf]

Appears OE - invoice had the 0031532828 pn referenced above and was ~$110 in 2009. EZL plug has a Mercedes star on it and 015 545 2828, followed by 072 51 923. There’s a logo below I can’t make out.

 

[gsxr]

Appears OE - invoice had the 0031532828 pn referenced above and was ~$110 in 2009. EZL plug has a Mercedes star on it and 015 545 2828, followed by 072 51 923. There’s a logo below I can’t make out.

That's the good stuff... OE, made by AB Elektronic. Unfortunately the date code is on the other end. With only 35kmi it should be fine.

 

[dionphaneuf]

Good to know! The shop that did that job is a bit inconsistent but nice to rule this one out. Some helpful diagnostic info on this too that I’ll look at once I fix some lower hanging fruit that could also explain the issues I’m seeing.

 

[Unavita]

Still resolving similar issue; waiting on/looking for SDS/HHT (help is welcomed).
I will say that I replaced the spark plugs (Mercedes F8DC4) with NGK BKR5ES and gapped to 1mm. The NGK's were in the car before (prior to my running isssue). They were far off from the the 1MM suggestion. I did find some oil on number 6 but assume this occurred before replacing the EGR system.

For whatever reason (again- looking for a diagnostic system) the engine changes at anything over above 80c. Then it is now running at 90c where it had never reached that temp. Throwing parts at it doesn't sound entertaining. I'll keep on looking for a reputable SDS. I've read all the nightmarish stories.

I replaced the thermostat a few months ago- could be the incorrect one though I purchased it at MB.

Caps, rotors, plugs, wires et al replaced about a year ago.

 

[Unavita]

Double checked to make sure the engine was getting coolant. Flow is lower than I am use to seeing but it is flowing. I had been concerned.
Changed the oil and watch it flow. Towards the end it was very clear that it was more than just oil. Very thin for 15w40. That got me to thinking that there is some other element in the oil. The coolant was not low so I don't think it's that.
I will check each fuel injector beginning with number 6 tomorrow. That is my prognosis.

 

[Unavita]

If its stuck rich then the O2 sensor is dead. Its not possible for the car to run rich constantly at such a high value.

Define "not possible"?