[MartynGrattage]

Hi, I think my warm up regulator has gone faulty on my 1984 280CE

She Starts up from cold okay but very very rich, carbon soot coming out the back and really really fumy...!!!!
Then while warming up tickover is quite erratic up to 1200 rpm and down to 600 rpm and running very rich.
Then when warm, quite low and very lumpy tickover and still runing very rich.
She runs okay when actually driving along, I have also noticed fuel consumption is also very high.

Do these syptoms fit with the WUR failing....? I have looked at previous posts and it would appear so.

I am going to check this thing out over the weekend, Nutz 4 Benz advises to check for voltage at the connector plug, which I will do - If there is no power, is there a fuse maybe to check...? Any other suggestions as to how I can firstly determine that it is the WUR at fault would be appreciated.

MB garage want $3500 for a new WUR to come from Germany, but my mate is breaking a 280E same year as mine - will the WUR fit and suit mine...?

If it is the WUR and I can change it for the new/old spare from the 280E - will I have to do anything other adjustments or should it just work....?

Appreciate your help,
Martyn.

 

[MartynGrattage]

one other question...

I have been tracing the wires for this...the wiring harness has the wires for the WUR and for the cold start valve - there is also another single wire that goes to another connector down below the inlet manifold not far from the WUR in the middle - WHAT IS THIS...I can't find out in my manual. The reason I ask this is that a while ago, when I was looking for a transmission issue I disconnected this connector and cleaned it up, I remember that a relay or something 'clicked' somewhere when I connected it back on (The ignition wasn't on so it took me by surprise) I did it a couple of times to confirm.....There is no click now though....??

So what is it, should it click a relay when I connect it, could it be part of my tickover problem or just another problem..? :crybaby2:

Cheers, Martyn.

 

[minas de cobre]

I have been tracing the wires for this...the wiring harness has the wires for the WUR and for the cold start valve - there is also another single wire that goes to another connector down below the inlet manifold not far from the WUR in the middle - WHAT IS THIS

So what is it, should it click a relay when I connect it, could it be part of my tickover problem or just another problem..? :crybaby2:

does the wire hook up to another injector like thing that is in-line to fuel lines running to the fuel distributor? if so it is a valve that is included in later k-jet systems to modify control pressure (along with the WUP), run by an ecu that takes input from an oxygen sensor, and if this is failing could cause problems, but i would think it would be the ecu failing if thats the case, dont know much about these, however.

other (cheaper) things to check out besides the WUP:

the cold start injector could be leaking.

fuel mixture adjusted correctly?

i was going to say make sure the plugs are getting spark, however if some of the cylinders werent getting spark i think you would be getting un-burnt gas smell from the tail-pipe rather than black smoke, which does sound like its burning really rich. but you're going to need new plugs now anyway, they're fouled now.

ditto for badly adjusted timing, but its worth looking into.

thats all i can think of- good luck

 

[MartynGrattage]

ECU...?

I don't know where the wire goes to, it just joins into the same harness as the cold start wires and the WUR wires harness and away out of site towards the fuse box and presumably through the firewall..?
I feel a bit stupid asking but I am not sure if I have an ECU and Oxygen sensor...how can I tell...?

 

[minas de cobre]

ok i thought you were saying the wiring was coming out of the harness and going to another device that was not either the WUR or the cold start injector, and that was under the manifold. thats what made me think it was maybe a control valve. usually mercedes don't use these, so you probably don't have it. if you do, you would see something that looks spark plug-ish sticking out of one of the exhaust pipes after the exhaust manifold.

really in my opinion your best bet is to tune everything first, make sure you have spark at the plugs, check air/fuel ratio, then check timing and idle speed, then see where you are at.
even before that i would make sure the cold start injector isnt leaking. if fuel is coming out of it when the fuel pump is running but the wire to the injector is disconnected, then its leaking and needs to be replaced. if it is leaking, its just dumping extra fuel into the intake at all times.

 

[MartynGrattage]

Thanks very much minas de cobre, it was the MB garage that diagnosed the WUR at fault so this is why I am going down this path....!!
I am going to take off the WUR in the morning, then take it apart to see if the metal strip is broken or if the thing is blocked up. I am also going to go and get the spare WUR and Cold Start Valve from the donor 280E - I hope they will be suitable. I am very concerned that she is not running at all right...
Cheers, Martyn

 

[minas de cobre]

well MB garage definitely trumps on-line speculation from the other side of the globe! good luck with it, sounds like you are on the right track.

 

[MartynGrattage]

I have found it..

Hi, I think I have found the problem...
The big main vacuum hose from the inlet manifold to the WUR is badly cracked / split at the WUR connection end......!!
I am just trying to get a new one now.

minas de cobre, you mention I will need new plugs as they are fouled, they are certainly black and carboned up but were literally only put in a couple of weeks ago..is it possible to clean them up or should I just replace...? Should I change them right now while I am fixing the vacuum pipe OR leave them in for a bit and run it to make sure all is well, and then change them after...?

Also, is there anything else that may need attention following such a rich run period...?

Cheers, Martyn.

 

[MartynGrattage]

Mmmm may not be the fix after all

Hi, I am waiting for Easter to finish so MB Garage is open for spares....
While I was doing nothing today I tried sticky (gaffer) tape on the vacuum pipe that is split - It didn't solve the problem....still the same if not worse, she even back fired today, still chugging black carbon out the back and running like crap.......things are pretty grim at the moment.
So, the question is what pressure is in that vacuum line, was I dreaming that good 20 turns of gaffer tape would fix the split...?
Or, may this is not actually the whole problem - perhaps the WUR unit is shot after all....? Would running the WUR with the split pipe and low / no vacuum for this time cause damage to the WUR....or perhaps a damaged / blocked WUR has caused the pipe to split....??
Any suggestions or motivational tips.....??
Cheers, Martyn.

 

[MartynGrattage]

WUR Pictures..

Hi, I have taken a couple of pictures of the WUR and one of the unknown connection.

You will see that my WUR has a nut and bolt on it, I have seen somwhere somebody referrs to making an adjustable WUR with a nut and bolt....??

Is this what I have got, done by a previous owner, is this good or bad..?

Can I try to adjust this right now or should I still take off the WUR unit and check it, then put it back on and try to adjust..?

Martyn.

 

[MartynGrattage]

A problem with the electrical connector. HOW DO I STOP THE FUEL DRPPING

Hi, a quick test across the electrical connector showed no resistance at all so I took the WUR unit off....!!

I have found that one of the electrical pins is pushed right in a bit corroded and too fragile and damaged beyond making a connection.

I have the unit apart and am waiting to get a new / old part from a donor 280E to replace the electical connector and maybe the bimetal strip as well if it looks the same.

My big question is how can I stop fuel coming out of the pipe on the car I undid, should I try blocking it up or is there a way to stop it properly...?

Would appreciate your help, it is going to be 3 Days until Saturday afternoon, and I am not sure what to do - I have put my oil drain container under there at the moment, nut ti smells like a petrol station in my Garage...

Also, would this electrical failure and the the previous vacuum failure add up to the massive problem that I have had...?

If I get stuck putting it back together, I will shout up..

Cheers, Martyn