2000 CLK320 Engine and A/C query - PeachParts Mercedes-Benz Forum

#1 07-26-2002, 07:16 PM

I have a 2000 CLK 320, with a problem with the engine:

The engine sometimes twitches in Park, Drive or Neutral (revs are around the 500 mark). I really want to sort that out but, dealer said needle in haystack, as no faults are showing on Star Diagnostics. I changed the Air Filter, no difference. Why is it shaking slightly, there are no problem if the car is creeping or moving.

also

I have a strange "gas seeping (hissing) noise out of the middle vents" occurring constantly when I have my A/C on, if I press EC then the noise goes away. So obviously it sound like A/C gas or something. My A/C seems to work fine, except this noise has now started.

Appreciate some tech help or fixes.

N

Gilly · #2 07-26-2002, 08:27 PM

How many miles are on it?
Are you the original owner or just picked it up?
Has the dealer done anything at all to try to fix these problems, or just your own experiment with the air filter? i mean other than checking for fault codes.
Has anything been done for the AC noise, does the dealer recognize the AC noise exists?
Gilly

#3 07-27-2002, 04:21 AM

I am the original owner.

It has done 23000 miles, and has only started twitching since November last year where I had done 19,000 miles. They had done a B service in December, but could not find the fault. What could trigger this problem? In motion the car is so smooth. Star Diagnostics found nothing, except something to do with my emissions control, but it was not serious (burns a little more petrol than normal but I still get 25mpg in city and freeway driving), as they don't have strict laws in UK. But no other checks, they said they will keep the car and try and look for it. I will try again. I did the air filter as it is easy, and an obvious start, the old one which was in december was ok, but i still replaced it. Could MAS, oil service, gunk in the engine, spark plug, counterbalance shaft? Not sure if it is a comman problem. People with the CLK430 are also having a similar problem. But thats a different engine.

About the A/c I had damaged the condensor, which was replaced and the a/c was said to have been recharged. Now the a/c is bloody freezing, which I guess is good, but the noise is constant coming and going every 5 seconds for the entire journey. Is there a leak somewhere?

Many thanks in advance

N

stevebfl · #4 07-27-2002, 11:28 AM

As to theA/C noise, the sound of refrigerant passing through the expansion valve is audible to most people. This can't be helped. The system in the new cars use a variable displacement compressor to control evaporator temperature rather than cycling the compressor as previously. During constant spped driving with constant heat the hissing of the expansion valve should be constant with this new system. The flow is varied by the variable displacement to achieve a constant pressure in the evap just above the freezing point of water.

Hard to say about the performance problem. If what you are feeling is any form of engine volumetric efficiency problem it should be easy for a tech to investigate. Part of the modern diagnostics is a funtion that allows the tech to view the relatively misfire calculation for each cylinder. Due to federal law the identification of misfires became a legal issue. The mechanism for misfire detection is to watch the speed of the flywheel.

After each firing event the crankshaft is accelerated to a point where it starts to slowing down until the next firing event. At a constant engine speed the crankshaft speed actually can be plotted to be a sine wave of sorts (acceleration and deceleration rates being different keep it from being a perfect sign wave.

Deviation from the average speed is used to proclaim a misfire once an arbitrary threshold is crossed. The diagnostics gives a bar graph representation of the speed differencial per cylinder. Whereas the threshold may be a number like 250 the standard deflection of a smooth engine often shows one cylinder with a deflection of 1-30 say. Way less than the misfire criteria but often enough to suspect a cylinder if the deviation are not random.

With this as a basis, the diagnostics allow the technician to reduce or add fuel in 7% stages up to over 25%.. If say the engine was running lean on one cylinder but the misfire ccriteria was far from crossed, a normal bar graph reading may show that cylinder with a higher deviation than the others. By reducing the fuel to all the point for lean misfire will be reached on that cylinder before the others. When this happens the misfire threshold will also be passed and if normally occuring a P030x code would be set (x being the number of the cylinder in question). This form of test finds those mixture irregularity misfires that are due to vacuum leaks or leaking or restricted injectors.

The diagnostics also allow timing to be altered similarly while misfire (crank speed) deviations are monitored. Sure wish there was such capabilities on K-jet cars.

Gilly · #5 07-28-2002, 12:42 AM

Steve and barflux:
Only a few more observations. I was thinking along the same lines as Steve on using misfire detection, my only other thought Steve is that Barflux is in Great Britain, and I am unaware of what the engine management setup is there, it may be different in the diagnostic regime than a US (OBDII) vehicle. But hopefully they can go into an actual value screen and check out misfire recognition, even though the threshold for a warning lamp may not be there.
But another thought I have is about the "damaged condensor" problem that was repaired. Just how badly was it damaged, just wondering if it were in a major front end collision, maybe there are some chassis issue (misalignment of engine/driveline/exhaust, motor mounts) that may be causing a vibration or resonance causing the complaint.
And also on the noise from the AC and the fact it is now "bloody cold" I wonder if an overcharged system could cause the excess low temps and a hissing noise? Just a thought, trying to put 2 and 2 together here possibly, especially if both of these concerns happened after the "condensor damage" was repaired.
Gilly

ps or another thought is maybe an overcharged AC system making the compressor turn harder, but not enough to make the belt slip, but laboring the engine and causing a driveability concern such as this? Maybe run with the climate control off for a while as a test to see if the driveablity concern disappears.

#6 07-28-2002, 06:42 AM

I had a small about 5mph accident with a truck reversing into it, which required the bonnet, headlights, grill, crossmember and condenser to be changed, but the condenser was just changed as a precaution. Nothing else was damaged, the oil cooler pipes just touched the condensor, but I was able to drive the car for a while with no problems. But the engine problem was there before and still the same after no worse or better. But the a/c was after. But they were going to recharge the a/c, is that a problem, seeing I don't know when it was done since I had my car.

Thanks always

Nick

joe p · #7 07-28-2002, 08:50 AM

During my time in the dealer I replaced several 208 heater boxes for noise from the center vents. I appears the vent seals come off and whistle.

112 and 113's use the same air mass sensor and will start reading lean across the board, in some cases just effecting the idle, in others, affest acceleration and overall power. Does your car have a slight surge on accel? This is a sign of the a/f mter going away.

I'm not sure about the UK's engine management system but, the US specs will do the following:

1) kill air flow meters (mass air flow)
2) stick egr valves
3) seperate front dampers
4) stick fuel pressure regulator (made into the filter here)
5) 202's and 208's have had fuel pump relay problems.
6) of course, the infamos oil control rings coking from the FSS and Dino oil combination.
7) front O2 sensors, both bad and connectors full of water, which can short ME out.

Of course this isn't across the board nor do every one of these do this. I'd be sure to look at the air mass readings, 16 to 21 hg at idle and if it wont make it over 350 when opening the throttle fully, replace it. On the US car you can moniter misfire but, you might not see a thing. It's been my experince that havin a replacement air flow meter around to "try" always helps, if the overall fuel trim is heading for rich limit, swap the a/f and drive it, if it starts moving towards center, there you go.

Joe

#8 07-29-2002, 07:17 PM

I will go back to my dealer with this and check it. If you think of anything else then please let me know.

Kind Regards

N

#9 07-30-2002, 03:25 AM

from the climate control or Comand or dashboard.

Also the rumble occurs when the climate control is off or EC is on, I revved the car upto 2000rpm and at about 1500 to 1750, the car vibrated quite a bit more than at standstill.

Nick

stevebfl · #10 07-30-2002, 08:07 AM

I'm beginning to think of this as more a motor mount type problem than a misfire.

#11 08-09-2002, 12:54 PM

Thank you all I just came back fom dealer and they did a Diagnostics test for me and also reset everything.

The results are as follows.

ECU TEST on Diagnosis Assistance System

ETC - 135 - CAN communication with the engine system is spoardically disturbed.

ESP - P1817 - Component Reversing Lamp has |¯¯ ¯¯| +

ME2-SFI - P0130 - G3/4 (Right O2 sensor, before TWC [KAT])

PSE - B1724 - The alarm has been activated through componet A26/5 (right interior protection transmitter and receiver unit)

HRA - B1488 - Component E1m1 (Left headlamp range adjustment motor) has -//-

HRA - B148C - Component E1m1 (Left headlamp range adjustment motor) has |¯¯ ¯¯| - or -//-

HRA - B1489 - Component E2m1 (Right headlamp range adjustment motor) has -//-

HRA - B148D - Component E2m1 (Right headlamp range adjustment motor) has |¯¯ ¯¯| - or -//-

PTS - B1246, B1247, B1248, B1249, B1250, B1251 - All related to the 6 parking sensor on the front bumper - The plug connection has poor contact or is loose, or the sensor or cable is faulty.

Also what does the following mean they where on the diagnostics report (but only the aboce had any faults)

ETC
ESM
ME2-SF1
AB
EIS
OCP
LCP
PSE
SAM
DCM2
DCM1
ESA-FL
ESA-FR
HRA
ICM
CDC
AAC

I guess the PTS and HRA maybe due to the accident, and I recently set off the alarm. But with the rest I would appreciate your help once again. And what do the symbols mean?

Regards

Nick

Gilly · #12 08-09-2002, 10:41 PM

As far as fault codes relating to your problem, I would think about maybe the code for the O2 sensor, the front one is very important.
That would be the PO130 code in ME-SFI.
The acronyms you have listed are as follows:
ETC=Electronic Transmission Control Module
ESM=Electronic Shifter Module (the shifter is a control module!)
ME2-SFI is in effect the engine control module. ME2 is the "series" I guess you could call it, and SFI is sequential fuel injection.
AB=airbag
EIS=Electronic Ignition Switch, which is the thing the key goes in to.
OCP=Overhead Control Panel, which is the dome light.
LCP=Lower Control panel, which is the window switches and all the other switches on the panel surrounding the shifter
PSE, that's kind of tricky, it's the pump under the seat which controls the power door locks, but has many other functions as well. I believe the acronym stands for pneumatic system equipment. There is another item referred to as the pse in the phone system, it's what integrates the phone handset into the fiber optics system for hands-free use. With this module the PSE stands for Phone System Equipment or something like that, they recently started calling it the HSE instead to lower confusion, the HSE stands for I believe Hand Set Equipment, don't quote me though. But on your test readout, it's for that central locking pump, which has many duties and can set fault codes, etc.
SAM=System Activation Module, it's in the front fuse box and has many various duties. Newer Mercedes have many of these.
DCM 1 & 2, those are door control modules, have varios duties regarding power windows, seat switches, and outside mirrors.
ESA FL and FR is the Electric Seat Adjustment modules, they are under the front seats and interact with the switches on the doors via the DCM's to operate the seats. The DCM's do the actual dirty work of operating the seats, but are controlled by the DCM's, as directed by the switches. FL and FR is front left and front rear.
HRA as you mentioned is the Headlamp Range Adjustment for the Xenon headlights.
ICM is the Instrument Cluster Module, the whole cluster is one big module now, 'bout the only thing you can replace is the bulbs.
CDC is the CD Changer
AAC is automatic climate control, or Automatic air conditioner to be correct about it.

Gilly

#13 08-10-2002, 06:22 AM

Since I have had the car codes reset, I was driving it all last night and noticed that the revs are now set at 550 at idle and not 600-700 as before, and now there is no shaking. I don't know if it will come back in future but at the moment everything seems to be fine.

Where is that O2 sensor and how many are there in the car?

Could just resetting the codes fix my problem? I didn't think so but the judging from the rev counter, something was done and works at the moment?

Also what does this mean:

ETC - 135 - CAN communication with the engine system is spoardically disturbed.

And |¯¯ ¯¯| + , |¯¯ ¯¯| - & -//-

Does everything else seem normal bar the accident stuff?

Nick

Gilly · #14 08-10-2002, 08:59 AM

The first 2 emblems on the print out mean short to power (+) and short to ground (-), and the third one -//- is an open ground circuit.
The code you mentioned about the CAN sporadically disturbed means the ETC is reporting that once in a while it can't communicate witht the engine control module over what is called the CAN, which is like a communication "bus" line, stands for "Controlled Area Network". Codes like this aren't always a problem, they can be set for a few meaningless reasons, such as maybe you start the car and one of the control modules is a little faster to "wake up" than the others, in your case the ETC may be a little faster to wake up, or the engine controller is a little slower. It'll log a code somewhere, but the system basically "shrugs it off" and keeps working. No big deal.

I am unsure if any of these codes you had, if cleared out, will restore normal operation. Too much involved. "Maybe".

There are 4 O2 sensors in a US car, sounds like you use the same operating system as we do (ME2-SFI), so I assume you are the same. They are located in the exhaust pipes near the front, one on each side ahead of the catalytic converter and one on each side behind the catalytic converter. The front ones are critical for the engine control module to set the mixture, it'll set various types of O2 sensor codes, the control module can sense when the O2 sensors have a problem. The rear O2 sensors aren't really as critical, primarily they are used to compare what's going into the catalytic converter to what's coming out to sense if the catalytic converters are working properly, called "cat efficiency". Who needs a pair of lazy cats hanging around under your car? Could get ugly.

Yes, in general the codes you had don't seem that unusual, that one for the reversing lamp, not sure what that one's all about, but doesn't concern me, seems you would get an exterior lamp warning if it didn't work, might want to make sure they are working (the reverse lamps).

Gilly

#15 08-11-2002, 04:48 AM

Thank you once again,

I have done 75 miles driving in city (mainly) and freeway over the last two days, and noticed no shaking at standstill. I am a little baffled as to how this has come around after resetting the car and the no shaking. I had noticed that the car temp rises to 95C and then comes back down to 85C which is the normal temp (which I guess due to traffic). The service advisor told me never to shift into Neutral when at standstill (which I use to do on the basis of to reduce the workload on the car at standstill), but just to leave it in Drive, which I am doing now which is different.

Is there anyway I can check the error code for the O2 sensor from the car?

How easy is it to replace the O2 sensor in question?

By the way, on a separate issue, I have noticed a 1.5cm crack on the passenger airbag surround? Why is that?

Kind Regards

Nick