Fuel distributor replaced and no change
 

I found used distributor on an engine a local tech had swapped out because the owner ran it hot. Tech said he knew the distributor was good because it was one of his regular clients. I opted to buy the entire airbox including fuel regulator, eha and MAF meter. Took it home installed it, flushed the injector ports with the fuel pump before atttaching the fuel lines. Installed it with six brand new Bosch injectors. I start the car and hold my breath. Let the car warm up and hit he throttle. Black soot from the pipe just like before. No amount of adjusting the 3mm mixture screw will stop it. Another $550 down the drain.

If this is true even with the EHA disconnected, then primary pressure must be too high - e.g., bad pressure regulator.

Steve

Well, you're not alone. From my experience, fuel distributers are the single most mis-diagnosed part in the world of gasoline-powered Mercedes.

Ron
http://germanstar.net

Can a plugged cat cause this? I know mine has been saturated in soot for a while now.

I have tried to only express technical opinions in this and most other posts.

Every once in a while I like to point out how cheap it would be to have a professional deal with the problem. Your in deep do-do now because you have neither the ability to test the new distributor or evaluate your current condition. I only say that because of your volunteered past results.

If you have 5 cylinders with no flow and 1 with flow you can condemn the distributer, but unless you find similar simple results with the new one you will never know.

One out of ten cars that I do diagnostics on (I only do the tough ones) busts my butt, but not the customers.

Let me tell you about one: it was a 1990 300CE (104 motor KE). I picked up the car at the customers houes and thought it might not make it in. it was raining hard. By the time I got the scope hooked up for a drive, it ran fine. Over the next few days I drove it a lot with my scope set to take a snap shop. The way the snap-shot works is I can choose the time interval...up to 30 seconds. I also can choose where my set point fits in the 30 seconds. Standard setting is I feel a problem and hit the snap-shot button. What I see then is the previous 15 seconds and the next 15 seconds from that point. Over a few days I caught misfires on three different cylinders. I tried plug wires, dist cap, coil, rotor, everything except the ignition conrtroller. I almost changed the crank sensor. I walked.....

One of my better techs that works next to me had been following the process and the car was parked next to him so he took the plugs out to see what he could see. What he saw fixed the car and it had nothing to do with the state of the plugs. What he figured out was the wrong plugs were in the motor! Never seen such a thing and its possible we put them in there. The plugs that were in the car were right for a 103 motor but not the 104 motor. They are the same heat range, same size, but they have a different seal type. One uses a washer and the other a conical seat. What this did is put the plug into the plug hole, which caused a misfire under heaviest loading conditions like high humidity and the load that comes from starting off in second gear.

I could go on for hours telling such war stories. We had many hours in that car, lots of dyno time and a bushel basket of parts. The customer is the city manager of a local town and has a city crown vic (police special) as a daily driver so the time we spent doesn't bother him. There will be no bill as it is very likely we put the wrong plugs in. (although we can find no records in the last two years... he doesn't drive the car much though).

Actually there will be a bill though as he was so happy we found it that he is going to fix that leaking head gasket.

so how do you deal with situations like this?
 

I was wondering how a professional would deal with a situation like this?

$550 is no small potatoes, and it still didn't fix it. I would be quite frustrated at that point, but if it was my car, and my diagnostic skills that reached this conclusion, I would accept it as the price to pay for learning and move on, but the bottom line is the car still won't work.

Cap'n, is there anyway you can toss the cat completely? Just stick a piece of straight pipe in there instead and see what happens, it should not cost much at all, and if the black soot is coming from the exhaust, then there might be something stuck in the cat causing this. I don't see how the engine would produce the soot unless you are burning oil, and you're not are you?

xp

Its hard to express how a professional would do it. To you it looks like a mountain to climb. To me its what I do every day. Likelyhood is that the problem is so simple I wouldn't even see the car in my shop (I only do the hard ones).

Most problems, even for experienced techs, boil down to something simple camaflaged under some poor assumptions. How about another example of one that toasted our...you know.

My best strategic tech does most of our BMW diagnostic work. He wound up on a 93 Audi 90CS 2.8l v6. The car is brought to us by the cheapest car wholesaler (that is cheapest wholesaler not cheapest car) in town. Knowing the source we should decline the business, but we are good guys.

The story is that it is a no start. He has already replaced the crank sensor. (keep track of the camoflage). We test the car and sure enough it has no spark signal or injector signal. After doing pin-outs of every terminal of the controller we have found that the controller is awake and capable of displaying fault codes. We cause a couple to be sure. Other than the codes we cause there are no codes. While testing all the controller inputs we come across some problems with the signal from the cam sensor and we replace it. Still no ignition or fuel pulse signal outputs from the controller. We are about to bail as with the known status of the customer we know he will whine after we charge him for the first hour of labor and there are a shop full of real customers cars.

Our diagnosis at this point leads us to thinking it is a controller issue. We spend some time finding a real cheap used one ($125) and with it installed there is still no ign or fuel control. *****!

At this point the professional says: I'll deal with it tomorrow! (as of course this problem has risen to my level - I of course suggested the cheap used controller at my tech"s controller diagnosis - diagnostic risk management is also my specialty).

Well what would you do??? I did the same thing, I went to the iATN archives and looked the problem up and in about three posts I had the answer. Those damn "A" fools have a engine protection strategy that turns the ign and thus fuel off when ever the syncronicity of the cam and crank are off by more than one tooth.

About an hour latter that thing was running like ***** with its cams adjusted and 65psi compression in each cylinder. This is where the professional really can get beat up. I should have turned down the job knowing the source. I/we were lead astray by his original work with the sensor and the further finding of no electronics. Normally we probably would have went right to cam timing. OF course when we take it apart we see the crayon marks and new belt where they had screwed it up... do you think they would tell you they did such? The job is just packed with irony, a psych would maybe have done better. The fact that we didn't know Audi used this unique strategy without setting a code amazes me but we will chock it up to learning and the fun of the final kill.

A professional handles it anyway necessary. A real professional then figures out what that problem should cost and charges for it. As it turns out a real professional wouldn't of had the problem as he would have known that startegy, least all those archive replies were from guys who had been there!

It wouldn't be fun if it was easy, but it is unfortunate that there is no way for me really to give you all any clue how far in the dark you are compared to a professional. The typical DIYer only lacks three things to keep you from having the same problems I do: Training, Experience and a half million in tools. Otherwise we could all do brain surgery!

Cap'n Carageous, I see you live in Georgia. Why don't you drive the car or tow it to Steve B? Just a suggestion.
Meza

Lastest on the fuel distributor saga
 

I dropped the exhaust pipes at the manifold. They will only fall about an inch but that's enough to 'see' the exhaust coming out. Start the car, let it warm, not a puff of balck smoke to be seen!! I hook up my DVMs. EHA is 20ma KOIO. Start car. Duty cycle varying continuosly between 47 and 52%. EHA steady at 3.6 with O2 sensor unplugged and near zero connected . Still not a puff of smoke of ANY kind to be seen, even when revved to 4000 rpm. Damn that thing's LOUD at 4000 rpm.:p

So, plugged exhaust making it run rich???

There you go Cap'n, it took me six months to figure out why my car was hesitating and like Steve said, it was something simple, someone didn't know what the EHA current should be set to.

From Steves story I would have to agree with everyone else that the best way to start solving a problem is to look at any recent repairs, I'm sure that would make things a lot easier in the case of the audi, but then again, someone people just don't like admitting to screwing up, yet it is a part of every day in the life of every human being :)

xp

Frankly, I'm in complete agreement with stevebfl. Being a do-it-yourselfer is a wonderful thing with many advantages, but it's important to realize one's limitations. And by limitations, that's not necessarily a consideration of just your personal skill or experience, but also of tools and equipment that you have at hand. Mercedes gasoline fuel systems are extremely complex and require certain diagnostic equipment that very few people have access to. And the fact is that many of the components involved are simply too expensive to simply swap out and cross your fingers.

Ron
http://germanstar.net

You "experts" are preaching to the choir here. I HAVE taken it to a tech. There ain't but two in this area. One is a known ripoff and the other kept it all day and didn't fix it. When faced with little or no choice you do what you have to do. Now, when all the philosophy moments expire can someone answer a simple question. Why does this car blow soot through the pipes and run lean out of the manifold?

:) - I have about come to realize that the W123/126 turbo diesel is about as complicated as I want my car to be (not considering the Honda which is pretty simple itself).

Cap'n I would suggest either getting a W123/126 turbodiesel or building a manifold that will allow you to bolt on a Holley:). Throw in headers and a straight pipe and it should be ready to roll in Gum Swamp:).

You ain't brought it to me Cap'n. Bring it by sometime and we will check it out:).

Hey Eng!!
 

BTW, What color do you want your room in the "Better Homes and Gardens Shop"???:D :D

How does the backseat sleep?:).

If she is ever successful in running me off;) paint it "broke blue":).

I'd be willing to bet that the backseat of a pristene 83 SDL sleeps pretty good!! But we'll do better than that. I have a BIG couch left over from my Dad's estate that you can sleep on as long as you share it with the babys (dogs). :D

If you remember, i had the exact same problem going on for months with my 300E.
After 17 hours of diagnosing and replacing various parts, the tech replaced the entire fuel distribution system with a used system just like in your case. That did it!

But here's the important part: He had the car standing for 2 days before he could start diagnosing it. He was waiting for a new catalythic converter for it. He told me that a clogged/collapsed cat would cause the engine to run very bad (run rich - low milage), no matter how perfect it is adjusted.

The black smoke you are seeing is the remaining soot in your cat being burned. And as long as it's there the engine will run bad and propably cause more soot in the cat.

My $0.02 is on the cat!

Freestyler

Freestyler, didn't your tech change the exhaust after the fuel injection? Was it still performing poorly until the cat was replaced?

He wasn't doing or changing anything before he could replace the clogged cat. He wouldn't be able to troubleshoot anything with a clogged cat, as it makes the engine run very bad, he said.

After i told him that my 300E had been doing less than 10 mpg for a period of 2 months, he immediately called for a price on a new cat, as he would bet anything on that it was toast. -It was.

He had seen cat's collapse from just cranking the engine over and over (fuel pouring through - no ignition).

Freestyler

Cap'n

Have you got the problem resolved?:)

I worked on it this weekend. The cat was defineately causing excessive backpressure. Just for 'test' purposes I enlarged the flow path to 1.25 inches(3.3cm). After reinstalling the header pipe with the precats and the main cat, I took it for a short spirited drive in the country to blow out any debris that might remain( and there was some). It felt like it had more power and response but I didn't drive far enough to measure fuel consumption. I will install the muffler system and check that later this week. One thing I did notice though, it requires about 250 -300 rpm less to maintain 60 miles per hour.

Hey Cap'n,

Were you able to clean out your old cat, or did you find that you have to install a new cat?

Re: Fuel distributor replaced and no change
 

[QUOTE]Originally posted by Cap'n Carageous
[B]I found used distributor on an engine a local tech had swapped out because the owner ran it hot.


Hello Cap'n Carageous

I will need to dismount one of these days the distributor on my 260E 1988, 370K km, and never did it before.
Have you taken any photo from the distributor top face and bottom face?

Pictures of these expensive parts are soo helpfull before opening everything that I would appreciate to see it before starting.

Help is appreciated.

Re: Re: Fuel distributor replaced and no change
 

[QUOTE]Originally posted by cc260E
[B]I had images but they got lost when my hard drive crashed. My advise to anyone except a trained tech would be to stay out of there! The inside of the distributor is full of parts that have to be precisely aligned and calibrated. I could not find a source for parts either. There are some good pics in several of my threads about fuel distributors. A quick search will yield some pretty good results. Good luck!!:)

The jury is still out, but .........
 

I drove the car 38 miles today (highway mostly) and it used about two gallons of gas. That ain't but 19 miles per gallon but it sure beats 12!! I have to go to Atlanta on business until Saturday so I won't know for sure until next week, but maybe, just maybe I'm on the right track!! More later. ;)

I would think you have to adjust the mixture after 'un-clogging' the cat. -Preferrable while measuring CO from the exhaust.

Mine went from 7 mpg to 23,5 after replacing fuel distributor and cat. -And a good mixture adjustment.

Freestyler

I am still having to run my car in open loop. The problem I had causing poor idle and engine stumbling and eventual stall is still there. If I leave it in closed loop by connecting the EHA(which came with the airhorn assembly) the engine will run worse and worse until it dies. All I can hope for at this time will be to get the basic mixture set and then try to track my intermittant electrical failure. But to almost double the fuel mileage has got to be a step towards the final goal, which is to make this thing run like a Mercedes! I still have hope!!:)

Cap'n

Great to hear you got your fuel mileage back (well, most of it if not all!).

If you run OK open loop and crappy closed loop, I guess now you ONLY have to deal with an electric issue!

Is your car running OK in open loop with the existing cat?

Cheers.

While not official, I think my mileage is back up around 22-23 mpg. It's starting to get cool at night so I have to deal with the cold start issue of running open loop. And yes, when the engine is warm it runs fine in open loop.

Great!

To me, the cold start issue (with the car in open loop) is just a little irritating but at least the car runs great!

You are now back in the ballpark with that kind of mileage.

Now, you have time to sort out the electrical issues at your own pace, whatever that might be...:D

So I guess the cat was not really an issue, huh?

Good show, Cap.

Yes the cat was an issue. Until I cleaned it out it was causing the engine to run rich even with a good fuel distributor. See this:http://www.peachparts.com/shopforum/showthread.php?threadid=75662

Did you clean your cat out in the shower?

How did you avoid not getting scratched?:D