My engine...what's wrong!?

[cawimmer430]

Hey guys,

I'm having a little problem with my dad's 1989 Mercedes 500SL. My parents visited me in Munich with the 500SL for a few days and took home to M?hldorf the BMW 118i - that was two weeks ago. Since then I have been stuck with the 500SL and have driven it around three times so that the battery remains charged.

Today I had to go to the supermarket to fill up my supplies of groceries at home. Everything was cool when I started the car up in my apartment garage but after I was done shopping and ready to go home, the car didn't start. Well at least not right away. After three tries the engine didn't start. I could hear the ignition system at work but there seemed to be no combustion and the motor didn't start. My first thought was that somehow the battery wasn't fully charged but I dismissed that thought because I had just driven quite a distance to the supermarket and I had moved the car on the Saturday. There should be ample juice in the battery.

So then I tried again. This time I extended the firing sequence and also pumped the gas pedal - only then did the engine start but in P or N the RPM was fluctuating between 900 and 400 (!!!) RPM. At 400 RPM the whole car would shudder and vibrate. My first thought was to get this baby home right away but when I put her into R the engine stalled and died. Now I had to repeat the starting sequence again (extending and pumping with the gas pedal) and this time the engine didn't die but it was shuddering because the RPM was fluctuating in the 400 RPM to 900 RPM region. At 900 RPM the engine is usually smooth but this time it was vibrating like crazy.

Then I noticed another problem - the smell of not fully burned gasoline. Was the catalytic converter malfunctioning? Or was this the result of my drastic start-up procedure? Because when I got home this smell of unburnt gas filled the niche in my parking spot. Another problem was that the gas pedal became unresponsive on the way home. I could floor the damn thing and the 500SL would accelerate as if it were a 1949 Mercedes 170D that took 1 minute to reach 100 km/h! At other times a light tap on the gas pedal (just a light tap!) made the car accelerate as if I had performed a kickdown...

WHAT THE HELL IS WRONG HERE!? I need help, badly!  

I already contacted my parents but they are in Austria for two weeks and I have a photography job to do in M?hldorf for the local museum this Friday. I need a car! Transporting my equipment via train is unacceptable and too much work. I would bring the car to the Mercedes Munich dealership if I had the time but right now I am a little stressed because of school work etc. and even if they sent a team to my place I don't have the time to watch over their backs etc.



My best guess is that something is wrong with spark plugs. We had a similar problem with the BMW 118i a few months ago. The BMW technicians had forgotten to properly screw in two spark plugs so our 118i began to shudder and vibrate and the gas pedal was behaving erratically (like in the 500SL right now). Could the 500SL have some defect spark plugs!? Or is there something more serious going on here!? HELP!  

[CALL_911]

The history and heritage are running low.

[cawimmer430]

Wimmer, buy a Lexus! They are soooooooo reliable! I have a 1977 Lexus ES (well actually just a Toyota Cressida with leather and a higher price tag and chrome TRD rims!!!)! Let me tell you! I have smoked BMW M3's with this thing and I have never, ever, ever, ever, never, ever changed the oil on this thing because it is soooooooo reliable! LEXUS 4 'EVA!!!!  

[mzziaz]

My mother in law had simular problems last summer with her Peugeot. Turned out a bad catalytic converter had clogged the clutch. First thing the autoshop did was to replace the clutch. 
Good luck. Let's hope its nothing serious.

[cawimmer430]

My mother in law had simular problems last summer with her Peugeot. Turned out a bad catalytic converter had clogged the clutch. First thing the autoshop did was to replace the clutch.  
Good luck. Let's hope its nothing serious.

Thanks for input.  


It just occurred to me - could this problem I have also be due to a faulty fuel line or fuel pump?  

[mzziaz]

 

Replace the first "clutch" with exhaust in the previous post.



Seems I'm unable to edit posts on my cell phone.

[mzziaz]

If you are lucky, it could just be a clogged fuel filter.

[heelntoe]

The history and heritage are running low.

Ouch.

[VTEC_Inside]

Check all the ignition wires and make sure they are firmly connected at both ends.

While you are there, inspect them for cracks or other signs of age. Might even want to wait until night time, fire it up, and watch for arcing.

[S204STi]

Sounds like an ignition problem like VTEC mentioned since you have unburned fuel exiting the tailpipe.  Check that stuff out first.

My mother in law had simular problems last summer with her Peugeot. Turned out a bad catalytic converter had clogged the clutch. First thing the autoshop did was to replace the clutch. 
Good luck. Let's hope its nothing serious.

Replace the first "clutch" with exhaust in the previous post.



Seems I'm unable to edit posts on my cell phone.

hahaha, I thought that sounded odd...

[r0tor]

I'd first ask your parents what the problem is that they didn't want to fix with the car 

[Pommes-T]

My English is too bad for this so...

mein Polo hatte manchmal ganz ?hnliche Spackungen. Bei mir wars so, dass manchmal, nach l?ngerer Standzeit Feuchtigkeit in die Verteilerkappe gekommen ist und dann gabs genau die Symptome.
Einfach mal die Verteilerkappe abnehmen, die Kontakte ?berpr?fen, ggf. mit nem Tuch abwischen und Kontaktspray raufballern. Ich bin mal ?berhaupt kein Experte, man k?nnte auch sagen, ich hab eigentlich keine Ahnung davon, aber vielleicht klappts! 

Viel Gl?ck mit dem Auto!

[Colin]

Darf ich mal uebersetzen?

Sometimes my Polo had the same ?. In my case, it seemed that sometimes after the car had stood a while, damp had got into the distributor and this gave the same symptoms. Simply take the distributor cap off, check the contacts, wipe them with a cloth and spray with them with (in the UK, something like WD40). I'm no expert, mind you, and I dont' really, have any idea, but it might help.... Good luck with the car.

Now if you'd written in Schwyzerdootsch, even after all these years listening to it, it would still have taken a lot longer to figure what on earth you meant!  

[sportyaccordy]

The history and heritage are running low.

Low blow man hahahahaha

Take it to a shop, it could be a laundry list of things... most importantly though, a laundry list of things you prob. have no business messing with anyways.

[Colin]

Actually, thinking about CW's problem some more.......... and I'm not an expert either.....

if the car fires, but the revs drop dramatically, that could be the idler that is faulty. I had that on a rental Passat, where the problem was so bad that once you were less than 1000 rpm, the car stalled and restarting took anything up to 5 minutes.......

if it is nor running evenly, it is possible that an ignition coil has gone.... this is quite common and as most cars have a coil per cylinder these days, the car will still run, but roughly and the fuel consumption will go up. You can have a coil that has not compltely failed so there are times when it will fire cleanly and others when it will not - in fact, re-re-reading your post makes me suspect that more than anything else.

I'm guessing that this car is pre the era when all any mechanic does is plug in the diagnostic computer lap top - that's what Audi Roadside assistance did for me every time a coil when on the the S4 (VAG cars are notorious for blowing them).

Viel Glueck, mein Freund!

[Pommes-T]

Darf ich mal uebersetzen?

Sometimes my Polo had the same ?. In my case, it seemed that sometimes after the car had stood a while, damp had got into the distributor and this gave the same symptoms. Simply take the distributor cap off, check the contacts, wipe them with a cloth and spray with them with (in the UK, something like WD40). I'm no expert, mind you, and I dont' really, have any idea, but it might help.... Good luck with the car.

Now if you'd written in Schwyzerdootsch, even after all these years listening to it, it would still have taken a lot longer to figure what on earth you meant!  

Nice! My Schwyzerdootsch is even worse than my english! Thanks! 

[cawimmer430]

Check all the ignition wires and make sure they are firmly connected at both ends.

While you are there, inspect them for cracks or other signs of age. Might even want to wait until night time, fire it up, and watch for arcing.

Thanks for the tip. I will definitely try that tomorrow but I need to see if I can spare some time tomorrow or Wednesday for a Benz service team to come and help me out if the problem is worse than I thought.

[cawimmer430]

Sounds like an ignition problem like VTEC mentioned since you have unburned fuel exiting the tailpipe.  Check that stuff out first.

[cawimmer430]

My English is too bad for this so...

mein Polo hatte manchmal ganz ?hnliche Spackungen. Bei mir wars so, dass manchmal, nach l?ngerer Standzeit Feuchtigkeit in die Verteilerkappe gekommen ist und dann gabs genau die Symptome.
Einfach mal die Verteilerkappe abnehmen, die Kontakte ?berpr?fen, ggf. mit nem Tuch abwischen und Kontaktspray raufballern. Ich bin mal ?berhaupt kein Experte, man k?nnte auch sagen, ich hab eigentlich keine Ahnung davon, aber vielleicht klappts! 

Viel Gl?ck mit dem Auto!

Danke f?r die Tips. 

Ich finde es nur komisch, das so eine Schei?e genau mir passiert ist. In der Tiefgarage, wo der Wagen gestanden hat, ist die Luft ziemlich feucht und nass. Meinst du, das Problem ist durch diese Temperaturen und Bedingungen enstanden? Wie ich schon erw?hnte habe ich den Wagen ein paar Mal gefahren und alles lief wirklich bestens, problemfrei insgesamt. So eine verdammte Schei?e! Ich brauche am Freitag ein Auto!!! 

[cawimmer430]

I'd first ask your parents what the problem is that they didn't want to fix with the car 

They missed the "Ultimate Driving Machine". Plus, the BMW was due for a scheduled service and I had no time to do it. It was a good trade. They take the 118i for a few weeks and I can have some fun with the 500SL.

[cawimmer430]

Low blow man hahahahaha

Take it to a shop, it could be a laundry list of things... most importantly though, a laundry list of things you prob. have no business messing with anyways.

I'm not an engineer anyway. I doubt I could tell if there is something wrong in the first place. In order to look at the spark plugs I need to unscrew the huge plastic covering above the massive V8 engine.

[Raza]

It kind of sounds like what happened to my brother's car.  Something about spark plugs and fuel lines, as I recall. 

How long have you been on your set of spark plugs?

[cawimmer430]

Actually, thinking about CW's problem some more.......... and I'm not an expert either.....

if the car fires, but the revs drop dramatically, that could be the idler that is faulty. I had that on a rental Passat, where the problem was so bad that once you were less than 1000 rpm, the car stalled and restarting took anything up to 5 minutes.......

if it is nor running evenly, it is possible that an ignition coil has gone.... this is quite common and as most cars have a coil per cylinder these days, the car will still run, but roughly and the fuel consumption will go up. You can have a coil that has not compltely failed so there are times when it will fire cleanly and others when it will not - in fact, re-re-reading your post makes me suspect that more than anything else.

I'm guessing that this car is pre the era when all any mechanic does is plug in the diagnostic computer lap top - that's what Audi Roadside assistance did for me every time a coil when on the the S4 (VAG cars are notorious for blowing them).

Viel Glueck, mein Freund!

Thanks for the information, Colin. 

This is a 1989 500SL and although there are some computer systems onboard, they're fairly low-tech by todays standards. There is no such thing here as a plug-in-diagnostic so the dealership (if it comes to that, which it probably will), has to literally open up the engine to see what is wrong. 

[cawimmer430]

It kind of sounds like what happened to my brother's car.  Something about spark plugs and fuel lines, as I recall. 

How long have you been on your set of spark plugs?

I have no idea, really. I do know that these spark plugs are fairly new and were "recently" changed (maybe a year ago or so). But the 500SL is usually only registered for a few weeks or two months at most. When it isn't used it spends its time parked in M?hldorf in an underground garage with damp and wet temperature conditions. The car is totally covered by a "car blanket" too. Do you think these temperatures are at fault here? Long term, I mean...

[Raza]

I have no idea, really. I do know that these spark plugs are fairly new and were "recently" changed (maybe a year ago or so). But the 500SL is usually only registered for a few weeks or two months at most. When it isn't used it spends its time parked in M?hldorf in an underground garage with damp and wet temperature conditions. The car is totally covered by a "car blanket" too. Do you think these temperatures are at fault here? Long term, I mean...

I'm as far from an expert as you can get here, mechanically, but it's possible that the weather conditions could have aided in wear of lines or wires, or something of the sort.  I remember when my brother's car started having problems, it was a few cranks before the engine would finally turn on.  I thought it was heat related (it was over the summer), but then later on we learned otherwise. 

In my truly novice opinion, I'd say if it's not the spark plugs, it could be the fuel lines, because he had both of those replaced before his car started running again.

[S204STi]

I have no idea, really. I do know that these spark plugs are fairly new and were "recently" changed (maybe a year ago or so). But the 500SL is usually only registered for a few weeks or two months at most. When it isn't used it spends its time parked in M?hldorf in an underground garage with damp and wet temperature conditions. The car is totally covered by a "car blanket" too. Do you think these temperatures are at fault here? Long term, I mean...

You may have fouled plugs by either crap fuel or water in the fuel.  That just occured to me.

[r0tor]

if this was a rotary forum i'd say its flooded... aww shit, i'll say it anyway!

[MX793]

Unburnt fuel small, loss of power and engine stuttering leads me to suspect misfire.  Could be as simple as a plug wire that has come loose and has an inconsistant connection.  Could be one or more fouled sparkplugs.  Could be the plugs just need to be changed.  Could be one or more bad plug wires.  Worst case is that there is a problem with the ignition.  Did those have a distributor or were they coil on plug ignition?

[r0tor]

I remember when my old Probe GT had a cracked distributor cap... every moist morning it would run on about 3 out of 6 cylinders.

[the Teuton]

Oh heck, this thread makes you realize how much German you haven't spoken over the last 6 months.  It's time to start going to German club again...