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Well.. Just got our '88 560SL back after 10 months. Long story, and I won't trouble you with it. It's not pretty. Bad news... got it back after someone put over 700 miles on it, let the oil get three quarts low (didn't even register on dipstick), let the coolant expansion tank run dry (that took, coincidentally, three quarts, too), and covered the cockpit with mud. Good news.. it seems to be running OK, and some engine oil, vacuum, and valve problems seem to have been fixed.

Just a quick, stupid question. The coolant overflow hose connected to the expansion tank and routed into the fender well had broken off at the tank nipple, and is brittle and hard as a rock; I tried trimming the end and trying to reconnect it but no dice... too much of the hose is rock hard and it just crumbles. Soo.. I'm faced w/ replacing the hose, but I can't figure out how to route it. It seems to be "stuck" inside the fender. Is the only access by removing the wheel well liner? I could just start taking stuff apart like I usually do, but figured I'd check here first before breaking more stuff than I have to.

I've been told that the car needs a new cold start injector. On this car, I've done the usual basic stuff myself-- plugs, wires, distributor cap/rotor, oil changes, etc. On previous Volvo 240s and an '82 VW Rabbit we owned, I've done suspension work, intake manifold gaskets, engine mounts, etc., but I still don't fancy myself a "mechanic" and I'm terrible at diagnosing/trouble-shooting. Mostly, I can follow directions and swap out parts. Is putting a cold start injector on a 560SL anything special or beyond me? Anyone wanna walk me through it?

And, yes, I don't own a shop manual. Since my access to an excellent local mechanic who has always been there for me when I got in over my head is no longer ... ummm... possible ... I guess I need to get one. Consider that advice already given, and I'll follow up on it.

Thanks, everyone.
 

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First things first. . . here's the Manual. This can also be accessed through the stickies at the top of this page.

https://www.startekinfo.com/StarTek/outside/11883/?requestedDocId=11883

My coolant overflow hose just sticks down inside the fender. Maybe spray some soapy water on it and yank it out.

The cold-start injector is right there in front of the air filter. . . with the fuel hardline attached to it and the blue bosch connector. Be VERY careful if you decide to change it-- when you loosen the line, fuel can spray out, so extinguish any ignition sources and wear safety goggles.

HOWEVER I would be interested to know the logic behind that diagnosis . . . often the recommendation is to change parts in the CIS system as a shortcut for diagnosis. Not saying it's wrong just curious as to why that.

Good luck!
 

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Thanks so much for the quick and helpful reply. I wish I could give you more info re/ the diagnosis of a faulty cold-start injector/valve. It's kind of part of the "long story." Short version.. very close friend and great mechanic (professional, head of well-respected shop...... not just the typical guy who THINKS he's a great mechanic) who's been a tremendous help and resource over the years told me he ordered a cold-start injector for the car 'cause it needed one. Unfortunately, he's out of the picture at the moment, and I don't believe he actually ordered one. I've searched around, and I can't find one.. autohausaz, eeuroparts... no dice. That's the source of the diagnosis.

The car starts hard.. catches right away, but dies right away too. Repeat three or four times, OR pump the pedal and keep it running, and then it runs but surges for the next couple minutes as it warms up. Then.. idles smoothly and seems to run fine. That's the symptom. I've read through the K-Jet threads, saved them, downloaded ThisIsDave's pdf files.. but woof... I confess I don't understand them enough for them to be useful.. YET. I was just starting to get a handle on the CIS fuel injection on my '82 rabbit before the shock towers rusted out... ;)

But, yeah.. I have a spacious garage, jack stands, a good floor jack, compressor and a decent amount of tools, and am willing and eager to learn. Looks like maintaining and repaing my wife's 560SL is now my sole responsibility. Wish me luck.. and I hope not to bother y'all too much..

Thanks again..
 

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You're not bothering us at all. That's what this forum is here for.

And remember that the only dumb question is one you don't ask.
 

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Thanks so much for the quick and helpful reply. I wish I could give you more info re/ the diagnosis of a faulty cold-start injector/valve. It's kind of part of the "long story." Short version.. very close friend and great mechanic (professional, head of well-respected shop...... not just the typical guy who THINKS he's a great mechanic) who's been a tremendous help and resource over the years told me he ordered a cold-start injector for the car 'cause it needed one. Unfortunately, he's out of the picture at the moment, and I don't believe he actually ordered one. I've searched around, and I can't find one.. autohausaz, eeuroparts... no dice. That's the source of the diagnosis.

The car starts hard.. catches right away, but dies right away too. Repeat three or four times, OR pump the pedal and keep it running, and then it runs but surges for the next couple minutes as it warms up. Then.. idles smoothly and seems to run fine. That's the symptom. I've read through the K-Jet threads, saved them, downloaded ThisIsDave's pdf files.. but woof... I confess I don't understand them enough for them to be useful.. YET. I was just starting to get a handle on the CIS fuel injection on my '82 rabbit before the shock towers rusted out... ;)

But, yeah.. I have a spacious garage, jack stands, a good floor jack, compressor and a decent amount of tools, and am willing and eager to learn. Looks like maintaining and repaing my wife's 560SL is now my sole responsibility. Wish me luck.. and I hope not to bother y'all too much..

Thanks again..
Did someone go mudding previously in your car?

I'm also curious what conclusion your friend came to with the cold start valve. What testing was done and why should it be replaced?

The cold start valve doesn't come into operation unless the outside air temp is below a certain temp. But we're talking cold, like in the 40s* F (Rowdie will no doubt come in and correct me shortly :grin). I know it gets that cold in central New York, but not at this time of the year.

The general failure mode of the valve is that it leaks. Did your friend remove the injector and put it into a jar, start the vehicle, and see if it starts to leak?

Even then, a leaking cold start valve would be indicative of a rich running condition and hard hot starts (like a failed accumulator).

Start with the basics:
1. What's the fuel pressure up to? Get a fuel pressure gauge and check against the FSM for the correct variables. Check your EHA valve and make sure it's operating in spec (the plastic thing that lives on the side of the fuel distributor).
2. You said vacuum stuff has been replaced. What type of stuff are we talking about? Was a comprehensive smoke test done? Your 560sl is similar to my 380sl and has the same plastic piping that has a tendency to leak and let in false air. Not to mention, there are gaskets and rubber donuts that live deep in block valley. Were these replaced?

It's my standard MO to mention this, but assuming the fuel pressure is good I would get out your duty cycle meter and check to make sure the air metering screw is correctly set. A lot of mechanics will muck with this screw in an effort to hide air leaks and bad fuel pressure. If you've repaired vacuum leaks, but didn't correct for this you can potentially get the same effects.

If the meter reads a solid 99% and doesn't move at all, you have further vacuum leaks that need attending to and/or the fuel system is out of spec.
 

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Discussion Starter #8
This is not true on a 560SL. The hose goes to a coolant recovery tank under the fender. You need to remove the inner fender to get at it.
Thank you, and everyone else, for all the replies. I discovered this today while having the car inspected, but haven't completely pulled the liner.. just enough to get a peek at what was going on in there while it was up on the lift. I'm assuming a length of any 8mm ID coolant hose would suffice as a replacement.. no specific part number, correct?

Car ran great after the usual rough starts for the 20 miles from my place to the inspection garage, but stalled once at a stop light about a block from the garage. After sitting for 45 minutes during the inspection and checks while up on the lift, it started well but stalled three or four times during the first few city blocks heading home, then ran beautifully afterwards for the rest of the trip. Just some more anecdotal information, just in case that gives anyone some more ideas as to where to start. I've been looking through the linked manual (THANK YOU SOOOO MUCH!!) and trying to wrap my head around the fuel injection diagnostic procedures. Right now, I probably couldn't even locate 90% of the components referenced, but I'll start the learning process. Should probably start another thread for that. For now, I'm glad to have recovered the car from the theft, have it street legal again, and have it in at least driveable running condition.

One other very strange symptom..Brake pedal feels nice and firm, and initial grab feels strong without undue pedal pressure, but emergency stops/lockups are not possible. Even if you really stand on it, the car just sort of comes to a stop relatively quickly, but nowhere NEAR as quickly as it should, and not even close to skidding. The ABS system has never worked (owned the car for 15 years), but used to pulse a few times upon first braking after startup, then the ABS light would come on and the brakes would work fine albeit w/out ABS. Never bothered me. About two years ago, the brakes started feeling like they do know. I've replaced the master cylinder, the booster, brake fluid, verified no leaks in the system, and the pads, rotors, and calipers all are good. What could possibly explain the lack of emergency braking power?

Way off topic... but wanted you folks to know I really appreciate the help. Gonna get this licked!

Best to you.
 

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Discussion Starter #9
Did someone go mudding previously in your car?

I'm also curious what conclusion your friend came to with the cold start valve. What testing was done and why should it be replaced?

The cold start valve doesn't come into operation unless the outside air temp is below a certain temp. But we're talking cold, like in the 40s* F (Rowdie will no doubt come in and correct me shortly :grin). I know it gets that cold in central New York, but not at this time of the year.

The general failure mode of the valve is that it leaks. Did your friend remove the injector and put it into a jar, start the vehicle, and see if it starts to leak?

Even then, a leaking cold start valve would be indicative of a rich running condition and hard hot starts (like a failed accumulator).

Start with the basics:
1. What's the fuel pressure up to? Get a fuel pressure gauge and check against the FSM for the correct variables. Check your EHA valve and make sure it's operating in spec (the plastic thing that lives on the side of the fuel distributor).
2. You said vacuum stuff has been replaced. What type of stuff are we talking about? Was a comprehensive smoke test done? Your 560sl is similar to my 380sl and has the same plastic piping that has a tendency to leak and let in false air. Not to mention, there are gaskets and rubber donuts that live deep in block valley. Were these replaced?

It's my standard MO to mention this, but assuming the fuel pressure is good I would get out your duty cycle meter and check to make sure the air metering screw is correctly set. A lot of mechanics will muck with this screw in an effort to hide air leaks and bad fuel pressure. If you've repaired vacuum leaks, but didn't correct for this you can potentially get the same effects.

If the meter reads a solid 99% and doesn't move at all, you have further vacuum leaks that need attending to and/or the fuel system is out of spec.
Thanks for the detailed suggestions! My car was borrowed/stolen by a close friend/mechanic who, unfortunately, is battling an opioid addiction, during our "mud" season. To most normal people, it's called "Spring," but in central NY, we get freezing temps and a ton of snow, followed by three weeks of mud while it all thaws and melts, then summer. When your addicted to pills, you don't worry about heavy boots clogged with mud when you get in a stolen car, I guess. As far as not getting temps below 40 deg this time of year; as of the past three days, you're right.. was almost 90 yesterday and today. Four days ago we had snow. You never know.. we'll probably see freezing a few more times.

Some questions? FSM stands for.. ? EHA? The vac "stuff" that's been replaced are some rotted lines, but that's all I know. I'll pull off the air cleaner housing and take a closer look. AND.. I'm going on the word of an opioid addict. Probably not all that reliable at this point. I love the guy like a brother, and don't mean to make light of his terrible situation. Just a little ..ummm.. perturbed with him right now.

I don't have a duty cycle meter, nor a pressure tester, and have never used either. Back in the old days, used to use a dwell meter and a timing light on the family VW Bus and a few other non-electronic ignition cars, but haven't in many years. I am MORE than willing to pick up recommended diagnostic instruments, and like to learn. Suggestions for a meter and tester? I do know that the air meter screw HAS been adjusted by "ear" by at least one local mechanic over the years.

If a duffer like me is going to do more harm than good, does anyone have a favorite shop w/in, say, 200 miles of Syracuse, that truly knows and loves these cars? I'm not what some would consider the "typical" Mercedes owner.. I don't buy new cars, my upper limit of purchasing a car is $15K and usually spend nowhere near that, and have driven almost all of my cars well over 200K miles. Saying that only because I can't afford our local Mercedes dealership's service prices. The parts guys, thankfully, have been great and very helpful over the years. Sooo.. a high-end boutique restoration shop catering to the upper Haggerty crowd will be beyond me.

Enough.. I really, truly, appreciate all the help!
 

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Where are you at? I went to school in Ithaca and am familiar with the region.

These cars aren't rocket science and if you have some wrenching knowledge you will gather everything up quickly.

The stalling is a telling symptom. I recommend you do not drive it any further until you have the basics covered, especially the braking issues.

FSM stands for factory service manual. It's the link to the startek site above.

The EHA is the electro-hydraulic actuator. This controls the fuel trim when the car goes into open loop mode. There are ways to check voltage on this, but in all honesty it should be good to go if it isn't leaking. It's the black box on the side of the fuel distributor (the aluminum thing that has a bunch of hard lines running off of it).

Go and purchase a duty cycle meter from your favorite hardware store. Your car has a rudimentary computer system that will help spell out some of your issues. These threads are for your same engine which are in the sedans and coupes. Still relevant given that the engine and brains are the same!

http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1551939-m117-cis-diagnostics.html
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/2720049-ke-jetronic-lambda-control-duty-cycle.html

Personally, I think you have some more air leaks to contend with. Those threads should be a good jumping off point for what you need.

Welcome to the asylum!
 

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Thanks so much! Those two posts made a LOT more sense to me than the other one's I've read so far... gives me a great place to start. Will be in touch...

Best to ya.
Which two posts? Name them or use the quote button.
 

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Discussion Starter #13 (Edited)
Which two posts? Name them or use the quote button.
Fixed. Should have used the word "threads" instead of "posts.".. that would have probably been clear without quoting the entire previous message. I'll keep trying to hit the right balance between necessary and unnecessary quoting.
 
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