[teb1963]

Hi, I hope someone out there can give some advice. My car has been a daily driver for the last month, and absolutely everything has worked like its brand new. ( I made the mistake yesterday of not knocking on wood when I was thinking how awesome this car has been)
Anyway, the car started fine when I left work today, it ran fine all the way to the bank 15-20 min. I parked the locked the doors the red arming light flashed in the mirror like it should have. I come out of the bank, dis-arm the alarm the green disarm light flashed as it should. Turn the key, all the warning lights come on like they should, it turns over like its a new battery in it. But does not start.
It has happened this same way when the anti-theft was tripped (red and green alternating lights in the rear view mirror) but the anti-theft does not appear to be activated. I have locked and unlocked with the key, same result. I have armed and disarmed with both remotes and the same result. The car shows 1/4 tank of fuel (the gauge has worked the way it should) I put in about a gallon of gas to rule out that. any advise is appreciated. Thank you. Terry

 

[alchemy]

Not to deter someone to come along with a more specific knowledge of your car and perhaps a more common problem but mine did something similar this summer. On mine the alarm system has been largely disabled and I never used it so yours could be the alarm, I don't know. On mine I fixed it by unplugging and replugging about every connection in the trunk and behind the panels and moving the fuses back and forth, all assuming a bad connection somewhere. It worked and my best guess was the green relay above the battery on mine. A very vague guess but it was something back there. I am going to look into it further myself because I hate the idea of my car being paraded through town on a roll back.

 

[teb1963]

Not to deter someone to come along with a more specific knowledge of your car and perhaps a more common problem but mine did something similar this summer. On mine the alarm system has been largely disabled and I never used it so yours could be the alarm, I don't know. On mine I fixed it by unplugging and replugging about every connection in the trunk and behind the panels and moving the fuses back and forth, all assuming a bad connection somewhere. It worked and my best guess was the green relay above the battery on mine. A very vague guess but it was something back there. I am going to look into it further myself because I hate the idea of my car being paraded through town on a roll back.

Thanks for the reply Alchemy, I am also against having it towed, the car has been lowered and would have a problem with a hook. I will try your suggestions. Its gotta be something simple as it was perfect 30 minutes prior to it not going.
Any other advise is still welcomed.
Terry

 

[rorypff]

Check that the fuel pump is activating also - relay in trunk, But it does sound as if it is linked to the alarm system.

Might even be the good old Crankshaft Position Censor has called it a day.

 

[tdoriot]

I'd check the fuel pump also. You should hear it when you turn the key. On a no start vehical, I always give it a shot of starting fluid. If it runs a few seconds you have a fuel issue. If not, ignition. Easy test. Don't crank it till the battery dies, and don't let any jackass within 10 feet with jumper cables. Jump it and your problems will exponentiate.

 

[teb1963]

Hi all, first of all, thanks for the replies. I went and pulled the fuse out of the green relay above the battery, it was fine. I also checked the fuses in the trunk, none of them seem like anything to do with fuel. I scratch my head in confusion, figure might as well try to start, It fired right up like there was never anything wrong.
Thank you Alchemy, I assume the fuse in the that green relay was the issue.
I am a happy camper again.
Cheers,
Terry

 

[alchemy]

Pretty sure that relay is for the fuel pump and I forgot it had a fuse and I meant to replug the relay itself. Fuses too though.

 

[ArcticDweller]

I scratch my head in confusion, :wtf:figure might as well try to start, It fired right up like there was never anything wrong....... I am a happy camper again.

Hi Terry:

BTW, welcome to the R129 Forum..... Best in the World!

Okay, back to your short-term problem with the NO START issue.

It's nice that your SL started right up, today, and it's working again. :thumbsup:

However, there was a reason that your R129 would not start after driving it for approx. 20 minutes. You just haven't discovered the cause, as yet.

I would not be surprised if the NO START condition reoccurs sometime in the future.

You now know that the problem wasn't due to bad fuses, or out-of-gasoline, or a dead fuel pump.

The problem seems have occurred after the engine had come up to full operating temperature..... was then left to sit a few minutes.... and then the NO START.

I don't know how many kms you have on your car, but you may want to keep in mind Rory's comment, above, on a failing CPS as the potential culprit.

Keep us posted...... if it's a CPS on its way out, the symptoms will elevate in a relatively short time.

In the interim, enjoy the Prairies in your R129..... RCMP radar can't easily hide behind wheat stubble, this time of year.

God Bless, Arctic.

 

[alchemy]

By how he seemed to described the cranking I pictured no firing at all just smooth "nothingness" cranking for lack of a better term. The warm start issue is usually accompanied by occasional random firing or backfiring (I assume).
There are three things in the trunk area that I personally know will cause that. The green fuel pump relay, one of the bullet fuses in the panel (I think) and at least one of the pins on that large black muti pin levered connector by the right trunk hinge. I'm sure there are more things and more things that will cause that throughout the car. I was once hoping for a thread to list all those that people were aware of.
I agree that it will probably do it again and I also think that it could be total luck and something completely different which is why I have left that car in the garage since it happened and driven the other car til I have time to confirm the problem. For mine I am guessing the green relay but I replugged and jiggled alot of other stuff too and it could be something that reset itself somewhere else on the car.
Sounds like where you are at too. If you are set to confirm now what it was I would love to hear what you find so that my laziness can pay off

 

[teb1963]

Well, you are right Arctic Dweller, I brought the car home (it ran for about 10 minutes as I am only about 6 blocks from the bank. I started it a few times as soon as I got home and everything worked as it should. I went to put it in the garage for the last time till spring and would not start. I left till this morning, I turned the key it started right up and quit in about 1 second and will not re-start now. I removed the green relay cleaned the pins hoping it was poor contact, but still no go. Its right in front of my garage door so I will push it in later today as supposedly the snow is coming. BTW the car has 96000 kms. And I would like nothing more today than taking it out 1 more time to look for the RCMP.

So I will keep watching this thread for new ideas. Im not a mechanic, but I can manage my way through electrical. Take care all. Terry

 

[ArcticDweller]

Hi Terry:

Thank you for keeping the Forum members updated on your situation..... it can be of great help to others who may experience the same problem.

And, sorry to hear that your R129 is out of commission. :crybaby2:

The good news is, that your Roadster died in front of your garage, and not in some remote town outside of Regina. :thumbsup:

The other piece of good news is, that with your MY1996, you can eliminate the various wiring harnesses' problems common with previous model years.


Okay, a couple of 1st-things-1st:

1) Keep your SL on a low-amp Battery Tender at all times. (If you don't already own one, CDN Tire sells a MotoMaster ELIMINATOR 2-AMP intelligent battery charger that works extremely well....... look for a 45% sale price from time to time)

2) NEVER, NEVER JUMP START YOU R129

3) DO NOT OVER-CRANK your engine trying to restart it. You can over-heat the Bosch starter motor, and/or you may damage a module.

4) If you want to diagnose the problem yourself, you will need two things:

a) Mercedes Fault Code Manual

Mercedes Benz Fault Code Manual

b) Code Reader for your model year


Otherwise, it's off to an M-B Dealer, or a good Independent garage you can trust.

There are a lot of "Could Be's" why your Roadster has a NO START situation. Reading the stored Fault Codes will eliminate potential hours of frustration and unnecessary fiddling, and will likely point you directly to the problem.

There are a lot of threads on this Forum on various Code Readers for your Model Year. Search them out and decide if you have the desire to become a mechanic and do a lot of your own work.

Personally, one of the side benefits of owning an SL500 was to keep my mind challenged and sharp..... although, sometimes, I got more than I had wished for. LOL

Terry, once you have decided what path to take, and if you wish to pursue the self-mechanic route, there are a lot of experienced members here to assist you through this.

Hope the above is of help.

God Bless, Arctic.

 

[alpac]

Sounds like a bad Crankshaft Position Censor to me.

 

[alchemy]

The normal warm start issue we usually encounter does not quite sound how you describe alhough I would not rule it out.
Usually the "warm start issue" is only after the car has warmed up will it not start and you must wait 30-60 minutes for it to start again. It may backfire or crank eratically like it's trying to start also. That problem, whatever it is, does not show in the codes, (95 and older) and I know of no one ever saying that a dealer found the problem not that someone hasn't somehwere in this huge forum. It would not surprise me if they would just replace a bunch of stuff and still not have it fixed. Repair shops, no matter who they are, are often not good at problems that are intermittent and with no code. The car owner will have an advantage in that type of problem because they live with the car.
Still, your problem could be the same as that of the warm start issue. Some swear it is the CPS, others the cap and rotor, some the fuel filter or fuel system. A bad connection somewhere is always a possible.
I'd say the first steps are to check "everywhere" for a bad or ugly connection and then read codes or have them read somewhere.

 

[alchemy]

One of my 95's has had the warm start issue for a couple years now but I learnd to deal with it til I feel like looking in to it. It only does it if it has been sitting a few days or more and will never ever do it if I drive it daily. If it has been sitting a few days or more it can be completely cleared up by forcing it to stay running more than 20 min or maybe 10-15 min at or above normal temperature (85C).

My next steps are not what they would be for others. I am going to check timing and fuel pressure when it does it and look at the cam sensor connectors.

The assumed bad connection issue that I first described yesterday was on the other 95. It was not like the warm start issue.

 

[teb1963]

Well, I'm back with same old problem. After leaving my car in the garage from Nov 2013 till 2 weeks ago. The car would not start the whole time it was in the garage, I was going to push it out to driveway so the tow truck could load it. I found I gad a dead battery so I charged it slow for a couple days, go to unlock the steering and put in neutral, turned the key and it fired right up after numerous tries in the last year and a half. It started fine every try for a couple days, I decide to go fill it up with fresh fuel, I made it 4 blocks and it died. I have it towed to a Indy and after $600. plus an oil change and a battery, and they figure that one of the relays in the trunk was bad. (I had bought two relays and changed the green one myself but it still didn't start for me) The car worked flawlessly for a week and the when I go to leave work today (16* C) crank and no start. One of my co-workers was searching my problems and whatever forums he looked at said something about a common wire-harness problem, and my independent mechanic said the same thing was probably the problem if it acts up again. Does anyone have any thoughts on that problem, as was just stated in this thread that my 1996 SL500 was not effected with the problem. Mine by the way does not have OBD2 it has the round plug by the fire wall on the passenger side. Not sure if it matters but my car came from Japan. Sorry for the long post. Terry

 

[wlb50]

AFAIK the wiring harness problem ended with MY 1995. It sounds to me like a relay but what do I know. A trick I learned about a faulty CPS is that if the car suddenly stops - you pour water on the CPS to cool it down - and it starts right up you know it is a bad CPS. But I am not aware of any problems of the CPS with the M119. The fact that you are having trouble starting the with the engine cool would tend to discount the CPS unless it is completely gone.

Are you sure it has no OBD2 plug under the steering wheel (towards the transmission tunnel) - mine is US compliant - but also has the round plug by the fire wall.

That Russian web site said my car was Japanese too - but it came into the US new - at Caliber Motors in So Cal

If your car is RHD then I would say it is Japanese

Back to your problem is it getting fuel and spark? I think there is a simple tool you can buy - hooks to a plug wire and lights up if you are getting spark

 

[gjenner]

Sorry to barge into this discussion late but I have to report that my 1996 SL500 has a body mounted engine wiring harness part number 120 540 55 32 sitting in my garage with very little insulation left on the wires of the engine harness.

this vehicle is not yet in a repair shop because here in my part of North Carolina I am having no end of difficulties searching for a lower cost reliable way to get it back on the road. prices currently are averaging in the $3,000 range and I am not about to pay that kind of money for a 19 year old car that has almost 100,000 miles and I drove daily for the past 11 years.

That above rant is because it frustrates me that (1) Mercedes will not officially acknowledge there ever was a problem with wires (2) Reliable Indy shops are hard to locate (3) It's stupid for me to try to fix it myself and nobody seems to have a suitable answer to my problem.

My VIN is WDBFA67F8TF126451

You can not know how I wish the biodegradable insulation problem DID end in 1995.

 

[gjenner]

PS I made a typo error in that wiring harness part number it is 129 540 5532

 

[ericahn]

OBDII codes

The normal warm start issue we usually encounter does not quite sound how you describe alhough I would not rule it out.
Usually the "warm start issue" is only after the car has warmed up will it not start and you must wait 30-60 minutes for it to start again. It may backfire or crank eratically like it's trying to start also. That problem, whatever it is, does not show in the codes, (95 and older) and I know of no one ever saying that a dealer found the problem not that someone hasn't somehwere in this huge forum. It would not surprise me if they would just replace a bunch of stuff and still not have it fixed. Repair shops, no matter who they are, are often not good at problems that are intermittent and with no code. The car owner will have an advantage in that type of problem because they live with the car.
Still, your problem could be the same as that of the warm start issue. Some swear it is the CPS, others the cap and rotor, some the fuel filter or fuel system. A bad connection somewhere is always a possible.
I'd say the first steps are to check "everywhere" for a bad or ugly connection and then read codes or have them read somewhere.

Hi, alchemy. I run into your posting while sweeping thru all posting for starting problem. I have a question here with OBDII scanner. Wouldn't it show any codes if the car has starting problem? Fuel pump relay, CPS, fuses or what have you? Scanner shows no codes at all and it even says "Green Light" on system status. The car cranks all right but does not start like Terry's. I hear humming sound from fuel pump when ignition on. Any idea?

 

[ericahn]

What would be factors causing NOT ABLE to START of 1996 SL500, not covered by OBDII scanner?