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Fri Mar 04, 2011 10:41 am

Hopefully Tram will see this...

86 MB 560 SL CIS 5.6 V8.

Missing a cylinder, runs real rough. Ignition is spot on, all vacuum leaks are fixed (there were 6, mostly rotted hoses and cracked thermo switch ports) and it still misfires at lower RPM range.

Get the car out on the highway, get the RPM's up and that car will push you back in the seat as it takes off like a rocket.

Checking for fuel delivery I'd crack each nut on top of the fuel distributor, fuel would ooze out and an obvious misfire would occur as the fuel supply stops to that cylinder.....until I came to # 1.

No fuel oozing out, I can totally remove the pipe, no fuel. It is plugged solid or 100% malfunctioning. I still have my "normal" misfire.
I don't know what these look like inside. I've been told for a core credit that if it has been opened, forget about it, they don't want it. Based on that I've not delved into it.

Am I correct to assume I need a new Fuel Distributor or is there some magic potion I can pour in or a spell that I can cast upon this vehicle to heal it of it's woes?

Am I doomed to ante up and pay the piper for a rebuilt unit or am I overlooking an obvious cheap fix?

Thanks for any help!

Let me add that this car sits a lot, sometimes for months at a time. I know that's not good for any car but........

Dave

Fri Mar 04, 2011 11:17 am

djkeev wrote: Hopefully Tram will see this...

of course he will

Fri Mar 04, 2011 1:49 pm

First, try a can of "Sea Foam" plus a bottle of ATF in about 1/2 a tank. Run the piss out of it. If it's gummed, that should fix it.

If that doesn't work, search eBay:
http://cgi.ebay.com/ebaymotors/MERCEDES-FUEL-DISTR..._653wt_667

Lots of bargains here.

Fri Mar 04, 2011 4:33 pm

Thanks for the guidance. I'll try it and see what it does, Saturday is forecast to be nice. Any excuse for a Ride!!

Any advice about storage to ward off future issues?
Dave

Fri Mar 04, 2011 5:29 pm

djkeev wrote: Thanks for the guidance. I'll try it and see what it does, Saturday is forecast to be nice. Any excuse for a Ride!!

Any advice about storage to ward off future issues?
Dave

Sta-Bil in the fuel tank with a full tank should help a lot.

Fri Mar 04, 2011 5:51 pm

That's no doubt that it is your Fuel distributor. But there's no reason to buy a new or even reman'd one, unless you like wasting $2000, like the previous owner of my car did. Boy was I happy to see a Bosch reman'd sticker on the side of my FD! :lol:

A good used one from any late model 86-up V8 Benzer (420SE,SEL,560SEL,560SEC, obviously 560SL) will all be suitable donors to your car and it just drops right in. I usually sell them for around $100 on eBay so that's what you should shoot to pay. One thing I would check with the seller is the "stroke" of the piston/pin on the bottom of the distributor. It should have a slight amount of positive action when you press on it and should bounce back under its own power. If that pin just slides in and out when you turn the distributor upside down and then right side up....then its already lived a good, long life and isn't worth buying. If that makes sense at all.

Here's some good CIS engine-bay porn from a (post-detailed) engine in a 560SL that I fixed n' flipped last year. So complicated looking, but yet so simple! Germans....

Fri Mar 04, 2011 5:56 pm

Thanks for the advice. I am curious about what went bad inside to stop it from injecting on one cylinder. I really do not know how they work. Any feed back or helpful sites?

Dave

Fri Mar 04, 2011 5:58 pm

djkeev wrote: Thanks for the advice. I am curious about what went bad inside to stop it from injecting on one cylinder. I really do not know how they work. Any feed back or helpful sites?

Dave

Could be a split fuel filter, crap in the tank and a bad filter, etc. Filter should stop any contaminant by the time it gets to the distributor. So I would replace the fuel filter for sure!

The two main forums for stars are:

http://www.peachparts.com/shopforum/
http://www.mbworld.org/forum

Fri Mar 04, 2011 7:16 pm

Thanks for the links.

Let rephrase, I know how fuel injection works, I know the basics of CIS and how that works, what I specifically am mystified by is the fuel distributor itself.
What makes it rotate ?
How does the speed of injection change?
The plunger controlled by the throttle plate lifts and lowers a control pin, what does this pin control?

Thanks

Dave

Fri Mar 04, 2011 8:01 pm

djkeev wrote: Thanks for the links.

Let rephrase, I know how fuel injection works, I know the basics of CIS and how that works, what I specifically am mystified by is the fuel distributor itself.
What makes it rotate ?
How does the speed of injection change?
The plunger controlled by the throttle plate lifts and lowers a control pin, what does this pin control?

Thanks

Dave

The pin controls fuel volume.

Fri Mar 04, 2011 8:02 pm

It doesn't rotate per say. It's a simple mechanical distributor. I'll let these two pages directly from Bosch explain it way better than I ever could try.

Fri Mar 04, 2011 8:12 pm

John M. wrote: It doesn't rotate per say. It's a simple mechanical distributor. I'll let these two pages directly from Bosch explain it way better than I ever could try.

Here's a link to the whole manual online:

http://www.scribd.com/doc/3299223/Bosch-KJetronic-Fuel-Injection-Manual-#outer_page_20

Sat Mar 05, 2011 6:25 am

Wow !! You two combined are the best! Thanks a lot!

Too funny, I had both the Bosch K Jetronic and L Jetronic books like you linked to back when I worked for MB in the 70's and early 80's. I threw them away about 5 years ago thinking "why would I ever need these?" (as so often happens when you clean out old stuff!)

Memory is kicking in now, the fuel is continuously being injected into each cylinder all the time. The distributor while feeding each injector is simply controlling and metering the proper amount of fuel.

So, having one cylinder completely blocked, delivering no fuel, is most likely a simple clog from the metering needle into the #1 injection upper chamber. :-k

Ok, not a nice day, warm but overcast and drizzle, grandkids are sick so that visit just got canceled, maybe some seafoam and ATF and go for a ride!

Question, is there also a link to the L jetronic manual ? I know, I'm being pushy now!!
Never mind, I found it!! :lol:

http://www.scribd.com/doc/46351121/Instrucoes-Tecnicas-Injecao-Bosch-L-Jetronic

Thanks again guys!!!!

Dave

Sat Mar 05, 2011 6:59 am

John M. wrote:
Here's some good CIS engine-bay porn from a (post-detailed) engine in a 560SL that I fixed n' flipped last year. So complicated looking, but yet so simple! Germans....

What I like about the CIS system is the lack of wires to go bad, get wet and do all that weird stuff old wires tend to do! Yes, it does initially look intimidating but it is frighteningly simple! One of my main issues is rotting rubber, vacuum line ends, and also brittle plastic vacuum ports.
Fortunately Mercedes, in a manner very UNLIKE VW!!, has elected to support their history with an almost complete replacement part supply house in California! I've yet to be "no" by my local MB dealer. I told them "no" like yesterday, $640 for a steering wheel!!!!!!

Dave

Sat Mar 05, 2011 2:36 pm

djkeev wrote: John M. wrote:
Here's some good CIS engine-bay porn from a (post-detailed) engine in a 560SL that I fixed n' flipped last year. So complicated looking, but yet so simple! Germans....

What I like about the CIS system is the lack of wires to go bad, get wet and do all that weird stuff old wires tend to do! Yes, it does initially look intimidating but it is frighteningly simple! One of my main issues is rotting rubber, vacuum line ends, and also brittle plastic vacuum ports.
Fortunately Mercedes, in a manner very UNLIKE VW!!, has elected to support their history with an almost complete replacement part supply house in California! I've yet to be "no" by my local MB dealer. I told them "no" like yesterday, $640 for a steering wheel!!!!!!

Dave

How many steering wheels you want?
http://shop.ebay.com/i.html?_nkw=mercedes+steering...m270.l1313

Sat Mar 05, 2011 3:03 pm

Wow. Classy (for a boat, maybe). :lol:

http://cgi.ebay.com/ebaymotors/MERCEDES-107-123-12..._639wt_939

You're right. Vacuum leaks tend to be the biggest pitfall on older Mercedes, but it really depends car to car. I've never touched a single vacuum hose on my car, haven't needed to, yet. I'm very careful when working in the engine bay. But the same can't be said from some PO's mechanic.

Going through and replacing all the rubber hose ends, and plastic vacuum line will take an afternoon of slow methodical work and a few beers. I've literally touched every bolt and nut on my 300E in the past 3 years. Every job was straightforward, tools always fit where they need to without hassle. I can't say I've worked on too many cars, where parts are R&R'd like someone actually took the time to think " Oh yeah, someone is going to have to replace this down the line, lets make it easy for them to do that". Working on even a BMW from the 80's-90's is a serious WTF moment compared to any Merc. :roll:

It is nice that you can go to the dealership and request anything and have it in your hand seconds later (for a cost of course :D) When the guy brings up an exploded view in their EPC of every single screw and fastener in your driver door and asks you which one you want....on a 25-35 year old car, that's awesome.

Sun May 29, 2011 5:59 am

I'm thinking of adapting a V8 Mercedes CIS system to my 7.0L V8 Oldsmobile engine.

Am I crazy? I think it could work with intake mods and adjustments to increase the fuel delivery.

-Rich

Sun May 29, 2011 6:47 am

richardsteinburg wrote: I'm thinking of adapting a V8 Mercedes CIS system to my 7.0L V8 Oldsmobile engine.

Am I crazy? I think it could work with intake mods and adjustments to increase the fuel delivery.

-Rich

Anything can be done when enough time and money are thrown at the process.
Can it work? Sure it will! There will be a long line of obstacles to overcome along the way though.
Personally I think that you will be in for some serious headaches.

Dave

Thu Jun 02, 2011 10:48 pm

Just a side note, I've got an AMG from the early 90's and have found that if I let the car sit without driving it for more than a few weeks it starts getting an attitude.

As a result I fire it up and take it for a nice hard drive once a week.

And this is on a car with the early HFM system. After you get things sorted out, maybe just take it for a drive every once and a while.

I also had a W124 with a later CIS system on it. If I remember correctly there was a plunger of sorts in the fuel distributor that could be adjusted to mess with how much fuel was being injected at idle, but I believe that was a general control and could not be used to tune an individual cylinder?

Not sure on that one, been a few years since I owned that car and I was not too into working on my own cars yet.

-Paul