An owners repair nightmare.

[embe560sl]

I feel I want to share a repair nightmare with you all.
The problem started after getting my 89' 560SL out from winter storage. It started up no problem, but emitted a rich sooty and smelly exhaust. I thought a long 80 mile freeway run would cure this but unfortunately it didn't. The problem just got worse. It needed some expert help so I deck towed it (not wanting to cause any further component damage) down to the main MB 'stealership' for a diagnosis to determine the cause. During the 3 -1/2 hrs billed time, the tech replaced the 02 sensor, leaned the mixture out, took apart and serviced the slide valve, checked he cold start valve and replaced the idle speed control module...parts & labor $1000.

On my way home I quickly realized the problem was still the same. So I towed it back once again the following day. This time they wanted me to leave it with them for a couple of days. After the second day, I called to see how it was doing, I was informed more parts were thrown at it (1) some sort of a sensor that fits into the manifold (2) an EHA valve (said to be leaking gas, but I never smelled any) (3) the wiring harness, rotor and distributor cap as the old ones were original and said to be sparking all over the place and were interfering with diagnostic readings? After all these replacements, the problem still persisted and then, it was decided to do a fuel pressure test.....it proved to be very high, into the 90's and should be no more than in the 60's....so (4) a new fuel pressure regulator was called for.
On the fourth day I was told it was ready to go, the tech had taken it out for a test run (1/2 hour was billed for this) and reported all seemed well. After paying the bill..this time $3000! I left the shop and knew immediately that something was not right. It had very unstable jerky acceleration and the tranny 'thumped' through gear changes....so I took it back and told the tech that it was not running rough. He looked p....d off, but I said come out with me and drive it again and see. During that run he tried to tell me everything was normal and all it needed was a good long run and suspected that it was now the tranny that needed a complete rebuild ( $4000) as he felt the thrust bearing or something was leaking which was causing the rough thumping shifts ????.
I said nothing, but by now I had had enough and after returning to the shop, I went in search of the General Manager of the 'stealership' and after finding him, asked him to please come and drive my car. He immediately agreed all was not well and asked me if I would leave the car with him, under his supervision for another week, apologizing and stating that it seemed to have 'fallen through the cracks' but would make sure it would be made right.
The 25th July is when I now expect the car back........I pray all will be well as I have had many sleepless nights over this and hope no forum members will have to go through a similar experience.

[Alkraut]

I feel your pain and anxiety. It's a shame that the dealer's shop lacked someone who had experience with the late 80"s V8s, as it sounded an awful lot like many of today's dealers with the "change-a-part-and-hope" methodology. Unfortunately, they charge all along the jouney, with no scrupples about previous parts and labor that didn't fix the issues. Best of luck with your pick up on the 25th. If that didn't fix it, maybe cut your losses and try to find an experienced indy.

[embe560sl]

Originally Posted by Alkraut

I feel your pain and anxiety. It's a shame that the dealer's shop lacked someone who had experience with the late 80"s V8s, as it sounded an awful lot like many of today's dealers with the "change-a-part-and-hope" methodology. Unfortunately, they charge all along the jouney, with no scrupples about previous parts and labor that didn't fix the issues. Best of luck with your pick up on the 25th. If that didn't fix it, maybe cut your losses and try to find an experienced indy.

Thanks for your condolences Alkraut, as you say finding someone experienced on these 'older' vehicles is very difficult and I don't know of any in my vicinity. May be it's time to let her go.

[ctaylor738]

I too feel your pain. The claims about the trans sound totally bogus-they probably knocked a vacuum line loose or disconnected the linkage.

But, I'm looking at the work that was done and the parts that were replaced, and the list is not that unreasonable (comments in CAPS):

- tech replaced the 02 sensor, leaned the mixture out, GOOD PLACE TO START
- took apart and serviced the slide valve YOU CAN'T TAKE THE VALVE APART, MAYBE HE CLEANED IT
- checked he cold start valve - SHOULD HAVE BEEN THE SECOND ITEM CHECKED and
- replaced the idle speed control module. WHY - NOTHING TO DO WITH THE MIXTURE.
- (1) some sort of a sensor that fits into the manifold PROBABLY THE COOLANT TEMP SENSOR, DRIVES THE MIXTURE, NOT BAD, DID THE SAME ON MY 560 WITH A WARM-UP PROBLEM
- (2) an EHA valve (said to be leaking gas, but I never smelled any) AGAIN, NOT A BAD THING, YOU MIGHT NOT SMELL IT IF IT'S A SMALL QUANTITY
- (3) the wiring harness, rotor and distributor cap as the old ones were original and said to be sparking all over the place and were interfering with diagnostic readings? IF THEY ARE ORIGINAL, IT'S TIME FOR REPLACEMENT
- After all these replacements, the problem still persisted and then, it was decided to do a fuel pressure test.....it proved to be very high, into the 90's and should be no more than in the 60's....so (4) a new fuel pressure regulator was called for. THIS TEST PROBABLY HAVE BEEN DONE EARLIER, BUT AGAIN, IT'S A REASONABLE DIAGNOSTIC TEST. ASK THEM WHY THEY DID NOT SUSPECT A FUEL PUMP ON ITS LAST LEGS, WHICH WILL ALSO CAUSE HIGH PRESSURE

ALSO MAKE SURE THAT THEY CHECK THE CURRENT TO THE EHA FROM THE CONTROL UNIT (CU). THERE IS A SPECIAL HARNESS FROM MB THAT ALLOWS A METER TO BE CONNECTED SO THAT THE ENRICHMENT CAN BE OBSERVED WHILE DRIVING.

IF THOSE READINGS ARE BAD, ABOUT THE ONLY THING LEFT TO CHECK IS THE AIR MASS SENSOR. WHAT MAY BE HAPPENING IS THAT THE SENSOR IS TELLING THE CU THAT THE THROTTLE IS OPEN FURTHER THAN IT ACTUALLY IS, AND THE CU IS RESPONDING BY PROVIDING MORE FUEL.

Good luck, and keep us posted. I will say, that for $4000 in diagnosis and parts, you should have a perfectly running 560.

[Roncallo]

Originally Posted by embe560sl

Thanks for your condolences Alkraut, as you say finding someone experienced on these 'older' vehicles is very difficult and I don't know of any in my vicinity. May be it's time to let her go.

Sorry to hear about your troubles. I wouldent jump at selling her right away. The problem is not your car but the technichian and dealership working on it. Hopefully they will give you some consideration on the bill and everything will be right when you pick it up on the 25th. Obviously this dealership has not oldtimeres that know these engines. I would recommend going elsewhere from now on.

John Roncallo

[embe560sl]

Thank you CTAYLOR 738 for your comments and consolations. The saga has not yet finished and the car is still at the 'stealership' awaiting release permission from the general Manager. My recent phone inquiry has uncovered the latest developments and to my horror they have put on yet another new part ....a fuel distributor and still they say the problem persists although now intermittently. They say it can occur within minutes or within hours of running and now blame the fuel as being contaminated with water and rust possibly causing more damage to replaced parts and injectors and are next about to flush out the charcoal cannister and fuel system etc, etc.
My head is reeling, I am confused, distrusting and caught up into a financial whirlpool, I am
dreading what the finale will be.

[ctaylor738]

I can't believe what I am reading, especially from a dealer experience.

Again, I would ask them if they have hooked up the little harness and checked the current going to the EHA as the car is started, warmed up, and driven. The manuals give very specific values for these conditions. Seeing what the current does when the problem occurs would provide a clue as to the real problem.

The other basic test that should have been done was to measure control pressure under operating conditions, and observe what it does when there is a malfunction.

If they replaced the fuel distributor without doing these tests, then they are just throwing (very) expensive parts at it. I suggest that you demand that they take the new one off, and have the car towed to a shop that has some diagnostic skills. If you can't locate one, have it towed somewhere safe while you do some research.

The rust and water theory makes sense because it sounds like the car sits for extended periods of time. But, why would they not check that out earlier in the game with the rather inexpensive step of changing the fuel filter? And it's just plain nuts to put a fuel distributor on if there is the possiblity of contaminated fuel.

All of the things they are doing are plausible solutions to your problem, but they appear to be doing them in a very random and incredibly expensive order as possibilties "occur" to them.

It's hard to diagnose from a distance. But if you brought it to my garage in its current state, here's what I would do:

Put the harness on and measure the current to the EHA.

- If it stayed within range when the problem hit, then the engine control unit is getting proper signals from the various sensors and is keeping the mixture properly controlled. I would then re-visit the cold start valve, suspecting that it is randomly malfunctioning. I would do this by removing the cold start valve, putting a rubber plug in the hole in the intake manifold and see if the problem recurs.

- If it jumps when the black smoke starts, I would suspect that the air mass sensor is telling the ECU that the throttle is wide-open when it is not, and causing the ECU to give the engine more fuel.

Again, good luck, and we all wish we could do more to help you.

[embe560sl]

Thank you Chuck for your comments. It seems you know more about the engine than the MB 'stealership' ...wish I lived closer to you Ha! I will try to challenge them on the points you made. The only thing they seem to excel in is their ability to add up the numbers at the end. The old classics are beautiful machines but lord help ya when they start needing replacements. Thanks again you have been a great help

[DanielG]

I thought Lynn Taussig had returned when I read the title of this thread!

Good luck on your repairs!

[embe560sl]

Please, if anyone else can answer ...... If the small piston inside the fuel distributor starts to periodically stick. can it be saved or Is it game over and time for replacement? Also, if the gas tank shows signs of some internal rusting, what can be done to it to make it okay to reuse? please your answers ASAP......thanks (89 560SL)

[ctaylor738]

If you are talking about the piston in the center that is activated by the airflow meter, usually it can be cleaned up with PB Blaster or other penetrating oil and some very fine steel wool. If it's massively corroded, then it needs to be replaced.

The gas tank can be "boiled" by a radiator shop, and special coating applied to the inside (Bill Hirsch sells one) if the rust is pervasive.

If it's not pervasive, remedies range from cleaning out the strainer in the bottom of the tank, replacing the fuel filter and keeping an eye on it, to removing the tank, putting rocks or a long piece of chain in it and shaking it to knock the rust off the surface followed by flushing.

I went the "boil and coat" route with a tank and it cost about $150.

[embe560sl]

Thanks Chuck.....once again to the aid.
The plunger (or piston) seems to move freely enough, no apparent sign of sticking or abrasion. The 'techie' tells me now that it is not only the piston that needs to be perfect but also all the internal springs and stuff that could be contaminated and corroded. He says it really can't be opened up to see inside ? Before spending a bundle $$$$$ on a new fuel distributor $2300 .....I think I will definitely insist he gives the old one a try once again as soon as the gas tank cleaning has been done. Radiator shop you say? Hmmm would never have thought. As far as how pervasive the rusting is?, its really an unknown factor as you can't see enough of the insides to tell....just at the bottom of where the sender unit is positioned you can see surface rusting, but on the very bottom around where the baffles are is
Just by chance Chuck, would you happen to know if in the States, generic fiberglass and or tanks are available for my model? New MB replacement is $2800 (out of Germany) Yikes !!
One last question if I may? If the sender unit was also water contaminated...is it bye bye time? Thanks a million once again Chuck you are a of a guy.

[ctaylor738]

Well, I think either the tech is talking out his butt or they are trying awfully hard to sell you a fuel distributor. Or both. Which, by the way, you can get a rebuilt unit from CIS Flowtech for under $500. Talk to Ron at GermanStar. The fuel filter on these cars is pretty stout, and, IMO would catch anything big enough to screw up the FD. That's what it's designed to do. So I would ask them to squirt some PB Blaster on the piston and put the FD back on with a new O-ring.

Personally, I would go either the "change the fuel filter in a month" or the boil-out route with the tank. I have not heard of generic tanks, but it is very easy to find used ones. Try www.car-part.com. There is no way on God's green earth you should buy a new one from the dealer.

Hang in there.

[embe560sl]

Your suggestions well taken Chuck and will be pursued.
Please excuse my ignorance but what is PB Blaster?

[ctaylor738]

It's a rust-buster and light petroleum lubricant, comes in a spray can, you can get it at any auto parts store.