W210 E320CDI black smoke and limp mode: Help!

[growlygrowler]

Hi all,

My first post on this forum.

The car is a 545,000 mile y2000 "W"reg E320CDI estate that I bought cheaply from a taxi company. My wife thinks it's cool that it's been to the moon and back and I'd like to fix it up for her.

Here's the problem:

The car starts up fine though occasionally misses a bit at mid-revs. There's no smoke at tickover and I can rev it to the red line standing without any smoke.

After a few minutes on the road the car goes into what I assume is limp mode (max revs 3k standing, 2.5k on the road) and it's slower than a very slow thing with "slow" written on it. It will gently gather speed to 70 no problem, but with some black smoke.

When it's working ok it pulls fine and I can red-line it though produces black smoke at high-ish revs under acceleration.

The local garage found an EGR code in the memory and broken vacuum pipes to the EGR. I also got an EGR actuator and we fitted that. Problem persists.

When I first got the car, the headlamp height adjust (halogen lamps) didn't work, so I assume there is (or was) a vacuum problem?

I had the same problem when I drove the car about 400 miles home, though after a bit of injector cleaner in the tank and 100 miles into good run it seemed to clear itself. The smoke persisted however.

I don't know when the injectors were last cleaned but I can get these checked locally. Would a leaky injector or two cause the limp-home mode, though?

Am I wasting my time and should this thing just go to the nearest scrapyard? Anyone got any ideas?

cheers

Dave

 

[rpe2]

Check the air filter is clean.

Re the EGR fault, did you replace the damaged vacuum lines you mention?

It may be the injectors, but I think its best to let a good independent specialist look over it first, if you let the forum know where you are located, I'm sure they'll be able to suggest somewhere.

 

[growlygrowler]

Thanks for that, Richard. Yes, I replaced the air filter (it was pretty mucky) but the problem's still there.

The local garage replaced the damaged vacuum hoses.

I'm located in Retford, north Notts

cheers

Dave

 

[rpe2]

The usual culprits are:

Air mass sensor, EGR Valve, Injectors, Inlet manifold flaps, and blocked intercooler.

These indies have been suggested on this site, I've no experience with either.

MB-NOTTINGHAM Independent Mercedes-Benz. 100% Mercedes-Benz. 50% of the price*

HAC Service Centre.

 

[growlygrowler]

Thanks for that. I'll get the guys at the garage to look a bit further or will try the place in Nottm you suggest

 

[davidbilyk]

Having used both I'd say MB Nottingham for diagnostics and HAC For repair and servicing, John at MB is very helpfull with Diagnosing problems and Carl at HAC is fantastic with service and price!!!

 

[DrNick]

Do a search on MAF sensor. I have no experience of the CDI but my 300TD (previous model - which also had stellar miles on it when I bought it from a taxi company) had similar issues and the MAF was the culprit, but doesn't thow a code. It also had a loose inlet manifold which didn't help!
On the TD you could disconnect the MAF and see if it made a difference as a first test. You could also meter the output, however, I believe the output from the later MAFs is digital

Others will be able to give a more definitive answer but worth doing a search.
Also worth looking to see if there is any air in the plastic fuel pipes as they are prone to airleaks which affects running, although usually this manifests itself as difficulty in starting.

 

[growlygrowler]

Well here's a bit of an update. The garage removed a couple of vacuum hoses and found them blocked up with soot. These were cleaned out and we had a good blast out in the car up and down the A1. It ran fine for 50 miles or so then went into limp mode. Resetting by removing the key allowed us to rev the car up, so we redlined it for a few minutes standing in a layby. There was a little smoke and a slight whiff of pub chips....

The garage read an EGR error code, so as requested pulled the manifold and EGR apart. The EGR valve and surrounding area were utterly crudded up with soot and gloop.

I suspect that someone at the taxi firm who doesn't know what they're doing had run the car on veg oil. To run straight veg oil it's necessary to heat it to 80degC to reduce the viscosity (or make biodiesel via transesterification process) - otherwise it's too viscous to atomise properly and it will burn incompletely - so I suspect that unburnt veg oil has got glooped up around the exhaust system and recirculation.

On my old 300D I installed a heat exchanger to make SVO work - but apparently someone lacking the requisite knowledge tried to pour old veg oil straight in without the modification. I'll get them to clean everything out before trying again.

Did I read somewhere that the EGR valve tried to open and close so many times before logging an error code and forcing the system into limp mode?

The headlamp adjusters still don't work, so I suspect further vacuum problems somewhere.

cheers

Dave

 

[DrNick]

Do a search on using vegetable oil in CDI engines on this forum. I think the consensus is that veggie oil in the CDI is a recipe for long term expensive disaster in the pump

 

[growlygrowler]

exhaust manifold heat exhanger?

Well, a bit of an update.

The EGR valve itself seems to be u/s. Of the two vacuum lines into the EGR, one seems to hold air, the other just blows out of the hole next to it. I'm assuming that this isn't supposed to happen??? It looks like I may need to replace the EGR valve, which of course only comes with the housing "mixing chamber" 613 098 0117 at £317 plus vat.

The EGR and chamber were full of soot and other grot. There did, however, seem to be some water in there. Now this could just have come from the exhaust gases but may have come from the heat exchanger on the exhaust manifold.

If this is leaking, then I think the car is beyond economic repair and I'll scrap it. However, do I really need this bit? Does anyone know what those water lines feed?

The chamber and EGR are part# 47 on the picture; the heat exhanger is part# 77. Helpfully it's called "heat exchanger"......

cheers

Dave

 

[lynall]

The heat exchanger just cools the exhaust gas down before it enters the inlet manifold, most modern cars seem to have similiar i have even seen this on trucks.

A little bit of coolant wont hurt for now i would try to get it running right then see if its using any coolant, no point in chucking good money away, then go from there.


Lynall

 

[alexander patie]

ok, the egr vacuum bowls can fail as yours apparently has. when this happens soot from the exhaust gasses is drawn into the vacuum tank on the o/s inner wing where it can block the turbo vacuum modulator as well. easy to unblock, but be aware of this scenario. the egr vacuum bowl is part of the valve and very pricey, although it is a two stage unit - you could try unplugging and blanking off the leaking bowl.

the coolant heat exchanger is used partly to heat water for the fast demisting of windscreen in winter from cold start. the pipe going from it leads into the heater matrix.

 

[lynall]

Pretty certain egr doesnt work from cold so no flow of exhaust gas equals no hot water.



Lynall

 

[growlygrowler]

Well here's a bit of an update.

Parts #47 and #77 in the picture were dud (heat exchanger and EGR vacuum actuator), and a series of small flaps on the inlet manifold had seized. Also the MAF sensor had died and the system had more black gloop in it than I've ever seen before.

The above parts were hideously expensive from MB UK so I bought used ones off Ebay in Germany (a complete inlet and exhaust manifold with associated parts for EUR45) and a new MAF sensor.

The car has (fingers crossed now just clocked up 548,000 miles) and has not gone into limp mode since the parts were fitted. It still smokes a bit when I really put my foot down, but smelly diesels all seem to do that. It pulls like a train and has returned 38 mpg on average (lots of country lanes and towns) and 45mpg+ on the motorway.

I have a few gearbox "funnies" with the car occasionally losing drive, one or two funny changes and refusal to change up, and on a couple of occasions the cruise control refusing to work and the tiptronic control doing nothing. However, pulling over and stopping&starting the engine resets things and they work ok. I might have to look into this if it carries on.

Does the gearbox have a control unit that throws codes?

I do have the exact ECU error settings written down somewhere, and will post these on the forum when I find them for future use by anyone else.

cheers

Dave

 

[alexander patie]

hi there, what was wrong with the heat exchanger then? it has no moving parts, perhaps it was clogged or leaking? glad you got it sorted.

 

[growlygrowler]

hi there, what was wrong with the heat exchanger then? it has no moving parts, perhaps it was clogged or leaking? glad you got it sorted.

Both. It was full of crap on both sides of the exchanger and leaking ever so slightly. Heat exchangers do degrade over time, so this didn't surprise me much

cheers

Dave

 

[Dieselman]

I have a few gearbox "funnies" with the car occasionally losing drive, one or two funny changes and refusal to change up, and on a couple of occasions the cruise control refusing to work and the tiptronic control doing nothing. However, pulling over and stopping&starting the engine resets things and they work ok. I might have to look into this if it carries on.

Does the gearbox have a control unit that throws codes?

Yes it does.

The gear change maladies could be low fluid, speed sensor, electronic plate, poor connection onto the loom, iffy selector unit.
The CC issue sounds like a wheel speed sensor may be faulty, which only MAY also be the cause of the gearbox issues.

Have the codes read.

 

[johnsco]

Check tyre sizes, as an odd tyre size can disable cruise control.
Last winter I fitted snow tyres on the rear of my E300TD.
CC immediately stopped working.
When I took them off at the end of February, CC came straight back on.

Cheers
Johnsco

 

[growlygrowler]

Thanks for that. I'll get my local garage to read the codes for me. I managed to reproduce the problem a couple of times and it seems to happen when I floor it going around a bend. I think it seems to happen more on right-hand bends, though this isn't conclusive. The dipstick on the autobox is actually missing so I'll order a new one (how the **** do you lose a dipstick???) but I chucked a litre of ATF in anyway. It's too soon to tell, and maybe it's my imagination but the changes do seem a little smoother.

If you happen to see a maniac testing out the kickdown round bends in a large silver estate car then it's probably me.....

cheers

Dave

 

[proser]

Dave,

the autobox dipstick is not missing as they never supply one with the car If you have problems getting one, then you can borrow mine to check the level.