87 560SL has been sitting ----- fuel problem
 

Good morning Guys and Gals,
I've been trying to breathe some life into my dad's old 560SL. It has been sitting about 5-10 years in southern Cal outside. The engine has good spark and runs if I use starting fluid.

What I've done so far is:

Replace fuel relay
Drain old fuel from tank.
Exit hose rotten, so replaced
new fuel pumps (2)
new fuel filter
replaced hose clamps and some lines on fuel pump assembly
checked for leaks

Now I have good fuel pressure to the fuel distributor, but that's as far as the fuel goes. The injector lines remain dry of fuel.
What is my next step before removing and trying to clean rebuild the fuel distributor?

Thanks for your help
Jeff

Do you have good fuel flow from the pumps? Pressure is one thing, but volume is important too.

Does the cold-star injector spray?

Try having someone cranking and go push down the air metering flap in the intake. See if you get fuel. Having sat that long without any attention, you could have a bunch of varnish buildup or corrosion inside the FD. If the FD is the issue, you're probably better off having it sent off for repair and calibration or pulling a known-good unit from a junkyard car.

AA:

1) Loosen the injector lines on the top of the fuel distributor (FD).
2) Remove pump relay, bridge pin sockets 7 & 8 so that the pumps run continuously.
3) Press down on air flow sensor plate; does fuel emerge from the loosened lines?

If yes, retighten lines on FD. Loosen lines at injection nozzles; check for flow at nozzles.
If there is flow at the nozzle inlets, the nozzles themselves may be clogged; they contain a fine screen and a check valve.

I suspect you are talking about a cold start injector of some sort, I am not educated on the KJet system yet, but the answer is there is no fuel getting into the intake manifold period, unless I spray starting fluid.

I have seen some people on you tube disassemble this FD, but never have seen the results and have read many say no as far as doing anything with this KJet system. I'm still interested in trying to just clean it up till I can start and move the car. I'd like to hear from anyone if they've had any luck cleaning. If not I would be grateful to have advice on where to send unit.
Thank you:)

Great spark, but absolutely no fuel to intake manifold, all the injectors and lines are dry. High pressure fuel and flow to the FD, have previously jumper-ed 7&8 that's why I added new fuel pump relay. Fuel pressure and flow are no problem now. Just nothing to the top of the FD (injector lines), the fuel injector lines are dry, no fuel to injectors.

Thanks for your time responding, looking for any suggestions on tuning up the FD (cleaning):)

The fuel distributor valve that lets fuel into the distributor is likely stuck , if you take airfilter off and push on airflow meter it should chirp slightly indicating fuel is flowing to injectors if you dont hear chirp , you may get lucky and try to unstick fuel distributor, you need to test fuel system with gauges

I guess I need to find out where and what the airflow meter is. Will research that and get back to you. Thanks!:)

Yes, there is a cold-start valve. It's up on the front driver's side near the valve cover.

The airflow meter is obvious as day once the air cleaner is removed. Remove the air cleaner cover and look in the hole. The big metal flap is the airflow meter. The airflow of the engine running pulls it down, and its deflection adjusts the fuel rate.

Okay that just validated what I thought. I jumpered the pins and had the fuel pumps running full time. when I pushed on the plate there was no chirping and however I had some sound of fuel trickling into the manifold. I suspect there is not fuel out of the injector lines, but I will check that next week when I get back from work.
Thank you much for your suggestions. I will update.:)

This is a good rundown on the basic operation of the system. You just add injectors and the electronically controlled EHA, if applicable.

https://www.youtube.com/watch?v=a4fJAfXYxWk&t=9s

Fuel Dist Replace or rebuild
 

The gasoline has likely varnished the inside of the FD making unsuable, or it may have even rusted the inside if the FD if the cast iron version. You can take your chances with finding a good used one around $300 (make sure to match the part numbers) that has a decent warranty. Used onse are just as old as your car though and may not last very long. If you are planning on using your dad's car and not just getting it ready to sell, seriously consider having it rebuilt for around $500 or a newly rebuilt one for around $600. eBay has some really good options. If you do a lot of homework, have the time to invest, are methodical in your approach, and are very, very careful, you could try to rebuild it yourself. The kits cost around $100.

Smart move on the pumps, just because the run does not mean they move any fuel.

5-10 years? I would spend the money on a reman FD. CIS Flowtech is the authority. Last I spoke to them the unit was about $550, cannot beat it.

AA:

Behind the fuel inlet fitting of the FD is a fine mesh screen; it may be clogged.
If that screen is clear, the FD could be removed, and an attempt made to ensure that the metering plunger is free to move. To do that, mark the location of the seal holding nut on the bottom of the FD (it is an adjuster for the stop position of the plunger), and then remove the nut. The plunger will now be exposed in its bore, and can be soaked with a thin penetrant.

Thanks everybody for your input. I am in the middle of painting the house now. I like to brush it on so it takes a while. 3 stories on back and one side, not as young as I used to be so taking extra care using the ladder. Have some carpentry to do first.

However I did order a rebuild kit for the FD, and will get back on that hopefully within a week or two. Standby, I'll let you know how it goes!

Still Trying no fuel
 

Good morning gentlemen,
I could use your help figuring out why I’m not able to get any fuel into my 1987 SL560. It had been parked for years and when I got it home the first thing I needed to do was replace brake master cylinder. With that done tried to get the car running. I noticed that I could not hear the fuel pumps run and after testing them, I ended up replacing both fuel pumps and the fuel filter. I replaced the fuel relay also. I drained the fuel tank and ended up replacing the fuel tank outlet hose that was rotting a braking up as I tried to cut a piece away.
Now I had excellent fuel pressure, still no start.
I checked for and have good spark, when I used starting fluid the engine started immediately for a second or two.
Next step, I noticed that when I broke the connection between the fuel injectors and the fuel distributor that I was getting no fuel. When I cracked the EHA or fuel in line to the fuel distributor I had good pressure and copious fuel. I had read that the fuel distributor could gum up from the ethanol fuels and I ended up rebuilding the fuel distributor. The inside was pretty clean, but the diaphragm was starting to degrade. Anyway with that done I still am not getting any start.
I don’t know if the EHA is the correct term for the part on the fuel distributor, but it appears to be a electro hydro mechanical fuel shut off from what I have read. I applied 12 volts to the EHA and could hear a faint click like it was opening. With a small rubber hose I blew through the unit and it opened and let air through when I applied voltage, so I don’t think it is that. I have the KE-Jetronic fuel system.
I am trying to educate myself on the Bosch CIS system, and I believe with the cold start part of the system that the engine should start, at least try to start, as long as there is fuel to the system. If anyone can help me determine where the road block to the fuel is in my system, I would be greatly appreciative.
Things I have done so far:
• New Battery
• New fuel relay
• New fuel pumps
• New fuel filter
• New fuel tank exit hose
• Fuel distributor rebuild
Any help would be greatly appreciated.
Jeff

There was someone on Benzworld about 5 years back with the same problem, and I think it turned about to be his MAS (the air plate thing).

I am rereading all the posts and systematically trying these process now. I cannot believe that all my fuel injectors could be clogged, but am tending that way now. I checked the cold start injector yesterday. There is fuel pressure to it, but with the fuel pumps on and the air flow plate pushed down, there is still no sound or smell of fuel.

I am rereading these posts and will check fuel pressure to all the injectors today.

Okay , here is an update I have checked the FD upper outlets to find they are dry. I've tried jumpering the 7-8 to get the fuel pumps to run continously. When pressing down the airflow plate thete is still no sign of fuel (ether a chirp or sound or smell of fuel). There is good fuel pressure to the bottom of the FD ( by loosening the return line I get good spray and flow). Same on pressure measuring port. When I break the cap on the cold start injector there is good fuel pressure and fuel, however it is obvious that that is far as the fuel is getting. That injector is not opening either. I have tried loosening the upper FD lines (several at a time) and using either the 7-8 cross jumpered for fuel pump running and also with the fuel relay reinstalled to crank over the engine. All the upper fittings remain dry.
These are all the same indications I had before rebilding the Fuel Distributor (FD). What can I check next?
And I told my dad this would be an easy fix:) Help

Jeff

Have you changed the fuel filter? It is located in the fuel cluster just aft of your right rear wheel. That cluster includes two fuel pumps. BOTH must run, the filter and a valve (don't recall the name) that maintains fuel pressure for easy restarts.

The entire cluster of components is easy to dismount and test or rework on the bench. Clamp your fuel line closed before removal. Inspect your filter carefully. If it shows signs of serious contamination, you may be faced with removal and cleaning of the fuel tank. Not uncommon after extended storage.

Just reread the posts and found that you did change the filter. Check it again. If the tank is seriously contaminated. it could be clogged again.

Ive seen the injectors get stuck and not squirt fuel , get a small punch and hammer and with the fuel pump bridged or key on lightly tap the top of each injector at the cylinder head side, worth a try

Lots of fuel and the accumulator is working well also. I used a rebuild kit and made sure that I took my time on the FD. I should at least get some fuel through the cold start injector shouldn't I? I have plenty of pressure and fuel to it, i.e. I've been sprayed pretty good when I break the connection to the injector, but that is where the fuel stops. There is no audible sound of fuel reaching the manifold. No smell of fuel. Thanks for your reply every little bit helps. Makes me think:)

It may be time to suspect the fuel pressure regulator. A certain minimum fuel pressure is required to open the diaphragm valves in the FD, irrespective of the position of the sensor plate and metering plunger.
Cracking the fuel supply and return fittings may produce what appears to be good pressure, however, absent measurement of pressures, that is not definitive.

Just an update for all of these posts, and thank you very much.

The update:

I could not hear the fuel pumps run and after testing them, I ended up replacing both fuel pumps and the fuel filter. I replaced the fuel relay also. I drained the fuel tank and ended up replacing the fuel tank outlet hose that was rotting a breaking up as I tried to cut a piece away.
Now I had excellent fuel pressure, still no start.
I checked for and have good spark, when I used starting fluid the engine started immediately for a second or two.
Next step, I noticed that when I broke the connection between the fuel injectors and the fuel distributor that I was getting no fuel. When I cracked the EHA or fuel in line to the fuel distributor I had good pressure and copious fuel. I had read that the fuel distributor could gum up from the ethanol fuels and I ended up rebuilding the fuel distributor. The inside was pretty clean, but the diaphragm was starting to degrade. Anyway with that done I still am not getting any fuel to the intake.
I don’t know if the EHA is the correct term for the part on the fuel distributor, but it appears to be a electro hydro mechanical fuel shut off from what I have read. I applied 12 volts to the EHA and could hear a faint click like it was opening. With a small rubber hose I blew through the unit and it opened and let air through when I applied voltage, so I don’t think it is that. I have the KE-Jetronic fuel system.
I am trying to educate myself on the Bosch CIS system, and I believe with the cold start part of the system that the engine should start, at least try to start, as long as there is fuel to the system. If anyone can help me determine where the road block to the fuel is in my system, I would be greatly appreciative.
Things I have done so far:
• New Battery
• New fuel relay
• New fuel pumps
• New fuel filter
• New fuel tank exit hose
• Fuel distributor rebuild
Update: I have checked the FD upper outlets to find they are dry. I've tried jumpering the 7-8 to get the fuel pumps to run continuously, then pressing down the airflow plate there is still no sign of fuel (ether a chirp or sound or smell of fuel). There is good fuel pressure to the bottom of the FD (by loosening the return line I get good spray and flow). Same on pressure measuring port. When I break the cap on the cold start injector there is good fuel pressure and fuel, however it is obvious that that is as far as the fuel is getting. That injector is not opening either. I have tried loosening the upper FD lines (several at a time) and using either the 7-8 cross jumpered for fuel pump running and also with the fuel relay reinstalled to crank over the engine. All the upper FD fittings remain dry.
These are all the same indications I had before rebuilding the Fuel Distributor (FD). What can I check next?
And I told my dad this would be an easy fix Help
From what I have read fuel pressure is very important. If it is too high will a valve stop it from flowing into the top of the FD?

I will be posting pictures of some of the items on or around the intake manifold and CIS that I am unfamiliar with. Maybe you can help me with the identification. I feel that I know what the fuel pressure regulator looks like. Does it work after the fuel return line from the fuel distributor? I think that I have read that fuel pressure is regulated after the fuel return from the FD. I imagine that to find the correct pressure inbound to the FD that I can open a threaded plug on the bottom portion of the FD and see if I can measure the pressure there. I'll try to get that done by tormorrow. Thanks for your reply

The "cold start injector" serves more like a choke. When the engine is cold, it sprays fuel to enrich the mixture. You still need the other 8 injectors functioning to start the engine.

Cracking the fuel lines tells you nothing about pressure. You need to connect a fuel pressure gauge (google for that information) and see what kind of pressure you actually have.

Getting fuel through the fuel distributor is all mechanical. When the center plunger is pushed up by the air meter, it lets fuel flow to the top and on to the injectors. Here you can see him pushing it up with his finger in a test rig.
https://m.youtube.com/watch?v=hRLorXbL1Us

Regarding the youtube video referenced above (post #28), the fuel distributor used for the "demonstration" is from a K-basic system, and the diaphragm valve springs operate in a manner that is the opposite of those found in the KE fuel distributor, which is the subject of this thread.

Thanks, good video, the follow up videos are even more enlightening. Much appreciated.:)

Thanks Frank, all these replies have given me more hope. I will be splitting the FD again just to make sure that all the ports are perfectly aligned on the fuel spindle with the FD body as well. I'll find out tomorrow and report.
:)

KE Jetronic is K with an EHA added. The EHA allows additional control of the fuel mixture, but the principle of getting fuel through the distributor via the center metering valve is the same.

If you swap the fuel lines over the drivers valve cover the car wont start, just fyi, ive accidently done that that's how I know,

Update: I have rerebuilt FD. I kept questioning my rebuild and think that it's 100%. I finally was able to get my helper (better half) to help me for a few minutes. I found that when I initally tried to start the car after the FD rerebuild, that it tried to start. After additional cranks it wouldn't fire at all. I found that by releasing some fuel pressure from the bottom of the FD (through the port pictured, ie. attached) that it would start for a couple of seconds till the fuel pressure built up again. It's definietely an over pressure, I will try to get a pressure reading and update soon. Any advice at this point. I need to know how the fuel pressure is regulated, and if there is a way to adjust or if I have to replace the bosch fuel pressure regulator.

AA:

1) What is the ambient temperature when trying to start?
2) In the event that you have not done this, use a piece of dowel or other reaching tool to depress the air flow sensor plate while cranking. This will require the cooperation of the aforementioned helper to operate the key switch, while you depress the sensor plate.

From your description above, it seems that there is pressure in the lower chambers of the FD, but not enough in the upper chambers.

Temperature was about 65 or 70 degrees in the shop where it's been sitting.
When the afore mentioned helper was cranking the engine I did just that, I worked the sensor plate up and down, with no change, but whenever I bled off some pressure from the port in previous picture, the engine started rigt up and then quickly died. We did this about a dozen times, this is when I realized I had heard something about having too much pressure to enter the top of the FD. Any ideas on that? I'm getting ready to do down and try blowing compressed air down the fuel tank return line to make sure it isn't clogged.

AA:

The temperature cited is above the cold start injector cut-off temp, so no help there.

If, from sitting a long time, the fuel pressure regulator (FPR) is stuck closed, the pressure in the lower chambers will indeed be too high, causing fuel cut-off.
Loosen the return line fitting on the FPR, and cycle the pumps. If nothing leaks out, the regulator is likely stuck.

Okay, this is what I just learned. I broke the fuel return line at the airconditioning hose (why do you cool fuel going back to the tank?)

I took the connections loose at the AC line and tried to blow air back into the tank. I would think that you would be able to do that and hear the air going into the tank etc., but I could not get any air through at 100 psi plus. I took the short fuel return line loose at the AC line that went to the fuel pressure regulator, and ran it into a jar. Voila the car started right up and ran till I shut it off the fuel was filling up the jar! Hurray, now what. Has anyone heard of a return line clogging up like that?

Next, I plan loosening the steel return line st the tank, to try blowing air through it again. I'll report back if I have any luck.

Thanks for the feed back:)

Interesting development.

Can the EHA be adjusted on the KE-Jetronic, and if so how? Thanks for any info.

The short answer to the above is: yes. There is a caveat; the internal adjustment of the EHA was intended for use during manufacture, rather than in the field, as it is a calibration adjustment of the EHA itself, as opposed to a mixture adjustment of the overall fuel metering system.
The field mixture adjustment is performed with the screw in the tower located in front of the FD.

Thanks Frank, so the adjuster is actually on the FD and not on the EHA itself? I'll have to look for it. Any ideas what to use to flush out plugged fuel return line?

His solution was wire and carb cleaner:

http://www.peachparts.com/shopforum/mercedes-benz-sl-discussion-forum/351154-fuel-distributor-leak-caused-clogged-return-line-1983-380sl.html

Yes, thanks for the link, I have actually seen that. That is what got me on the trail. I put some carb cleaner in where I broke the line at the AC hose and at the tank. Could not get air pressure from front to back so tried back to front and some started to come through then replugged. Went back to the front and filled the line up with carb cleaner then added pressure, and nothing, then about 15 seconds later heard it start to spit at the tank connection. Added more carb cleaner and wow, gross, any way that line is clear, it looks like I'm going to have to remove the tank to clean. When I opened the tank exit hose to drain the fuel that I had put in after installing new exit hose, I found the fuel exiting just a trickle. It poured out the first time when I replaced the hose. Means that the exit screen plugged up now, so tank cleaning looks imminent and new screen as well. Wow, and our admin wants to increase ethanol to 15% in gas. Man I hope I'm almost over the hill on this. I have too much to do:) Thanks for all your input EVERYONE:)

The Saga continues
 

:)Update after a copious amount of messing with wires, carb cleaner, and air pressure to clean out the clog in tank fuel return line, I looked for a used tank. Very quickly I determined my budget at this point would not accomodate 1100$ (lowest I could find). My drill and jig saw magically appeared and a 7 inch hole miraculously appeared in the top of my tank, directly above the fuel exit hose and collector tank. [I guess I should say that the local radiator repair shop said that the plastic parts inside the tank negated their ability to clean and coat these gas tanks]. Beware if you do such a thing that there is a fuel vent line that comes along the top of the tank, and you do not want to saw through it. I use a high speed dremel like tool to complete the hole.
I was easily able to use some wire to unclog what seems to be a venturi like orifice and bolow air and carb cleaner through the clog cleaning it out. Radiator repair people welded it back on and I reinstalled the tank and hoses.
Voila car started right up and ran. There was a lot of smoke initally and it started to clear up, but I had trouble trying to reset the airplate adjustment. My son had messed with it and I ran the adjustmet to the stop both ways. Are any of you able to tell me how to properly set the airplate, and what it actually does.
Any suggestions welcome. Thanks guys.:)