84 280CE fuel injection help
 

So I don't have much of a clue when it comes to identifying the EFI parts, although I do understand most of the terms.

Anyway, today I hear a backfire through the air intake when I started the car. I then noticed a roughness to the idle at the first stop light. Anything above idle and it feels better than ever as far as power goes and is running real smooth.

I get to work, and I notice the economy gauge is pegging halfway, even at idle, and in gear goes nearly to the red. When I get out in the underground at work I can smell the exhaust is running really rich.

So what am I looking at?

Vacuum leak (door and trunk locks ok, and no climate control)
Cold Start Valve
Stuck Injector
OPV (don't know if I have one)

Not that I'm going to touch it myself, I just like to have a little info before I take it to my Tech.

I have done a search, but I can't find much on the M110, or similar problems with the econo meter, rich running and rough idle.

Any help is appreciated

First to language, if youi have a 1984 280CE as you state, and not a 1974 280CE then you do not have EFI (electronic fuel injection). You do have K-jetronic. If it were a US car it would have had K-jetronic w/lambda and would have had a small amount of electronic control. The european 280CE had plain K-jet with no electronics (the idle air might have been electronically controlled but not fuel.

I would look for a vacuum leak or a defective decel dump valve.

Thanks Steve,

Yes it is a Euro, what else I've noticed is it is running a little cool, it is pegged right at 80, while I seem to think it normally is about 85-90, I did find the rad cap cracked, and no pressure when I removed it, it is possible it has been like that for a while though, I can't think when I last cracked it myself, and it had a service about a month ago.

The econo meter seems to give the biggest clues, once you are at cruising speed on the highway it seams to function normally, however as you slow in trafic it returns to the mid point and only returns to 0 on the overrun. Is this a red herring?.

Could the fact the cooling system has run unpressurised and at the wrong tempreture fooled the cold start?.

Phew! problem solved
 

Thanks again Steve,

While I was poking at my decel dump valve :D , I notice the crank case vent hose was off to the valve cover, I guess I dislodged it last week when I removed the air filter to change the distributor cap, and it took till now to work off.

So everything is back to smooth, if I was in your neck of the woods, I'd come over and kiss ya :eek:

Actually saved me $$ to, since I was prepared to go to the dealer today, but they have quietly dropped their Saturday Parts and Service.

The dealer would've loved to see your car come in for repairs! ;)

Glad that you solved it!
Your car looks so good in pictures. I wish mine was a Euro 280CE sometimes....

Then it probably wouldn't be this slow... :rolleyes: