OK guys, so, here I am; new to this site and have a problem....

I have my late father in Law's W208 CLK 320 to sort out. Purchased in 2004 with 114K miles, prior to that it was used daily. Since then it has been his Sunday car with regular, but light use. It is now at 132K and never had any breakdowns. Unfortunately he passed away in January and it has pretty much not moved since. In May i found it would start but would not engage transmission (auto) - it was stuck in Park. That was sorted by a local mechanic who did a "gearbox re-set"?!

And so it stood still again for ages (Garaged). Now... lately I am told by Mother in Law of the problems its having; Starts OK then will not re-start when hot. So she takes it to the local mechanic guy. (I look up your fantastic web forums and think - CPS!). Anyway local mechanic has it for 6 weeks and can't fix it, so I ask Mother in Law to drive it to my house (because it starts cold, right) and leave it with me - (I'm thinking - I'll change the CPS). Anway, it doesn't get here, but breaks down en route, and finishes the journey to me on a flatbed. I get the report from the local mechanic guy, and he's drained the petrol, changed the fuel pump and CPS, but still no success and listed a fault code - P2085. Today, I check it out for myself... The CPS does not look new to me, covered in dirt and no evidence of finger marks or replacement, plus the logo is Mercedes on the sensor - really? from a local guy? So I look under back of the car - think I can see the fuel pump, it doesn't look new, but it is definately working (why is there a thick wire hanging from the center of aluminium cylinder next to the pump?).

So I turn the key - it cranks but does not start (Cold) until the battery dies (I think the recovery guy drained the new-ish battery last night). So I connect to my car battery, and eventually after loads of cranking, it fires up, but really really splutterly, missing lots, and massive delay on revving the engine. 30 mins later the engine will now rev with less delay and the splutter at idle is better but still there. So I switch off... and try again... the engine is hot now... and it starts by itself with no connection to my car, but still lots (too much) of cranking. I have not yet risked trying to go for a drive - don't fancy breaking down away from home.

Guys - can you help me? Any ideas? My Mother in Law wants nothing more to do with it. I could take it to my local guy who runs a top quality, "1 down from dealership type" garage for a diagnostic, but don't fancy paying at this stage, nor do I want to take it to a Mercedes dealer - big cost.
I hear things like MAF sensor failure, ECU, Cam shaft, as possibilities. But maybe this could be more of a classic shortage of fuel problem?

You guys are definately going to know more about these cars than I, so anything you can offer would be appreciated.

(by the way, he had it re-sprayed only 1 year ago, it looks pristine! I don't want to get rid yet!)

By the way, I'm in Chester, England.

 

Has the Mass Airflow Sensor been changed?

check here http://autotechdiagnostics.com/?p=315

 

Hi Underlord,
I don't know if its ever been changed. Wife is off to Mother in Law's tomorrow - with orders from me to retrieve all paperwork about the merc.

Thanks for the link - I see the fault code for P2085 there.
Will come back to you guys once I know more on this.
Cheers

Just to add, this is the comment sheet from the local guy who took £££ from mother in law to not fix the car:

Diagnostics (reading P2085 EGT sensor 2, Bank1), checking contacts, terminals, switches & wiring including the repair to the secondary air pump. Replace fuel pump & Crankshaft Sensor. Labour. Complimentary wash & rinse.

(yeah right - complimentary clean becuase they couldn't fix it!)

 

Might be a good place to start, the MAF.

I googled Mercedes P2085 and that link came up, couple other ones too might be of interest to you.

Good luck!

 

I don't think the MAF would give you such problems. Anyway, you can disconnect it. The car should start and run without it, not great, but should work. Based on other's experience, not mine, you should make sure you replace the TPS.

 

I'd start with the CPS (because it sounds like a CPS, and they are cheap - $50 US, and you'll be SURE it's done), and then do all the maintenance: plugs, ignition cables, engine air filter, and fuel filter. After seeing the engine runs much better (trying not to do too much at once) I'd do the coolant, the brake fluid, the cabin filter, the steering gear bolts, check the motor mounts, and have the transmission fluid changed at a dealer (although some may prefer a less expensive Indy).

 

Thanks Guys, all these suggestions are really welcome. I'm going to get stuck in to this over the next couple of weeks, so I'll be back on again with progress reports and maybe further questions.

We run a Ford and BMW in our house, so working on this Merc will be new for me. I'll see if I can upload a photo of progress & the finished thing. Again, every comment is greatly appreciated.

thanks

 

Hi guys, me again.

So I haven't done any work yet, but still doing a bit of diagnostic work. My neighbour is handy with BMW's and has a diagnostic reader to plug in. So we've bought an adapter for the circular 38pin port and got some info ourselves this evening...

So, at first, just on ignition, we can see the following codes:
P20D4 - Load limit is active (we think this is why the ABS light is on)
P2017 - Weak right bank
P2086 - Again words to the effect of weak right bank

So, we start the engine, and its spluttery like before. We happen to remove the plastic engine cover as well. The live data coming out on to the diagnostic reader is showing generally good stuff, but notably the Long term Fuel trim is at 21% and the short term fuel trim is at 25% - both way above where the should be (i think). THEN we see a small air pipe disconnected from its mount towards the back of the engine, roughly above the CPS sensor. We think this is the return pipe from the fuel tank where the air is drawn into the engine to combust any vapour hangin around in the tank(?) Anyhow, we re-connect the small pipe and straight away the engine sounds less spluttery - and the Short term & long term Fuel trim readings switch to minus 25% & minus 21% respectively.

So we re-set all the fault codes.

Stationary, the vehicles sounds almost sound, only the occasional mis beat under revving. So we take it for a drive...

We are gone for about 25 mins, no faster than 30/40mph, about 6 miles, and we have got no power at all; if you push hard on the gas the car splutters ever slower but not cutting out; so if you are really careful and slow on the gas then you can get up to about 40mph, but any hard acceleration sees the car splutter and slow down.

We get back, stop the car. Immediately are able to re-start the car (as a test), then stop it again.

We try the MAF test - so disconnect the MAF sensor.
The car will not start at all, cranking, but no attempt to fire.

Plug in the diagnostic reader again, this time we see:
P2016 - over permissible limit
P2085 - Self adaption on permissible limit.
P2006 - Intake air sensor (Think this is the MAF)

So we return the MAF sensor - and loose the P2006 code.

But the car is now just cranking, and no attempt to fire.

And that's it. My neighbour (handy with cars), thinks it is not getting ennough fuel / getting too much air.

So this the end of this step. Neighbour has gone away to do some research, and I think you guys might want to comment so far.
I'm thinking the intermittant CPS issue might be coming forward now because the car will not start now its hot, - but that does not explain the fact it will not accelerate hard under load.

Cheers.

 

"My neighbour (handy with cars), thinks it is not getting ennough fuel / getting too much air." Did you replace the fuel filter? If you do all the things MarcusF is suggesting and have replaced the CPS and the MAF you may have other problems the a bad coil pack or engine and transmission mounts. could even be a bad fuel pump. Check the rail pressure. Faulty E & T mounts will cause the car to run bad at idle but I don't thing that would cause the no power when floored issue.

 

OK, Hi Guys, Thank you all for your help... Here's how it turned out:

So I spoke a friends friend over the phone who owns an independant mercedes dealership (miles & miles away). His advice was that it had to go on a Mercedes STARR dioagnostic machine, before I spend any more trying to solve it by trial & error. So I ring my nearest Merecedes dealer and get it booked in for some STARR treatment...

And the fault was a faulty fuel filter & pressure sensor (combined unit). This was replaced back in June by the local mechanic when he replaced the CPS & also Fuel pump. Problem was that he used a non merecedes filter/pressure sensor, and it was sending duff information and not enough fuel forward, plus when engine is hot it asks for a different level of fuel pressure, the dodgy filter pressure sensor was feeding wrong info and thus when hot the engine refused to start.

Took the Merc dealership 1 hr and cost me £215 to do the STARR diagnostic and fit fuel filter. Car feels like a rocket ship now by comparison.

So the local guy correctly fitted a CPS & that fixed the original fault, but then started messing around with Fuel pump & filter and thus created a new problem.

Am taking it out on a 300 mile trip tomorrow, see how I get on.

Thanks again everyone for all your help, I'll post you a photo of the car this weekend.
Cheers