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1992 500SL
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12 Posts
Discussion Starter #1
I have been having serious problems for the last few day, but for like 3yrs i have been always getting the hesitation when initially giving gas after work up.

Issues:
the serious problem was a few lumpy idle (like loosing spark to more then on cylinder), almost about to stall, backfiring, not accelerating smooth and sudden power lose on acceleration sometimes. these problem would ussualy come more when warmed up and sometimes it would run great, then back again.

It felt like it was a coil probable again (i changed both a year or two ago), so i changed the one that i thought was weaker (the right one). then seemed good for a short drive, but then problem came back, so i changed the other one too. then seemed great again but then after a long drive, and some speeding, the car was loosing most its power. it appeared to be running on only 4 cylinder.
i disconnected the right side coil and not much happened, idled the same. pulled the left on and it shut off. i pulled out the 1 and 4 cylinder connecters to the spark plug (they come from the right coil) and there was no spark.
i switched the coil main spark wire, between the 2 coils and the car wouldnt start at call (i dont know if its possible for it so start if there was no issues thou).

I change the spark plugs, distributors and rotors a year ago and the OPV relay 2 days ago. i was thinking the crank position sensor, maybe EZL??? HELP THANKS
 

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1992 500SL
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12 Posts
Discussion Starter #3
yes, i took it apart and cleaned the copper with some sand paper and it looks to be fine, but i don't know how the spark is not getting from the coil to the spark plug connectors.
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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10,969 Posts
If you have spark coming out of the coil but not the distributor, then the problem is with the distributor : rotor, cap or wire etc.
It is not likely all 4 spark plug wires are bad, so the problem is more up stream like the distributor (if the coil is good).
 

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Registered
1992 500SL
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12 Posts
Discussion Starter #5
update 2.5 hrs later

If you have spark coming out of the coil but not the distributor, then the problem is with the distributor : rotor, cap or wire etc.
It is not likely all 4 spark plug wires are bad, so the problem is more up stream like the distributor (if the coil is good).
Update

I just took out the right side rotor and it was cracked, so i put in an old one that i had laying around and the car started and ran good. i drove it for a little and thought it was fixed but it backed fired/ lost all power for a second (at 4000rpms ish). i dont know if i fixed it with the rotor or the cooling down fixed it. Any other suggestions?
 

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5,344 Posts
If the replacement cap/rotor is good you could easily have a second problem. Are you checking the fault codes on the 16 pin connector?
 

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1992 500SL
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12 Posts
Discussion Starter #7
i dont have a computer for that. im from Yew york but im in Croatian now, where i go to med school. my dad shipped me the car here.
its there something i can do with out the computer? i read about people reading some voltages from pins.
What are the possible suspects and how can i test for them, if i can?
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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10,969 Posts
Without the proper tools, everything is just a guess. and our cars may be a little too 'high tech' for the old world mechanics in that part of the world.
 

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1992 500SL
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12 Posts
Discussion Starter #9
haha, its not too "high tech" for here, they have official benz sealers and places for mercedes but that will cost more money and time, i need this car to get around every day. but if it comes down to it, thats what i will have to do. thanks for the replies so far!

What should i change next??
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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10,969 Posts
Well, like Dean said : run some diagnostic and see what it shows. It would be much cheaper than just changing parts to see if it works (unless you already have those parts on hand).
 

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Greek God of the R129
SL500-500SEL-190E
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8,371 Posts
You said that the rotor was cracked, the rotor brackets have been upgraded.
You may have the old ones?
That is why you are braking the rotors.
All new rotors are different then the old ones.

Regards,
aam.
 

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1992 500SL
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12 Posts
Discussion Starter #12
i chanced both rotors and caps like a yr ago, so the new one cracked. i replaced it with an old one.
 

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1992 500SL
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12 Posts
Discussion Starter #13
Update

update

i disconnected the battery and reconnected it, now seems to run good, like it did before :)

but still has the same preexisting problem for the last 3 years. after warming up, it hesitates/losses power on initial acceleration, then goes normal.
What could that be? i already changes the fuel regulator a while ago.
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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10,969 Posts
You mean the 'no spark' problem goes away after you disconnect/reconnect the battery ?
 

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Registered
1992 500SL
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Discussion Starter #15
You mean the 'no spark' problem goes away after you disconnect/reconnect the battery ?
no, it went away after i replaced the right side rotor. the random backfiring after went away after the battery unplug, hopefully it stays away.
 

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Premium Member
2015 Jaguar XF R Sport Twin Turbo, 1992 500sl Pano, 1999 CBR 1100XX, Super BlackBird, Jaguar X Type
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4,818 Posts
I have had a warm idle/pulling away at low revs issue for some time, gradually getting worse. The only likely suspect I have left after doing a code reader test on number 8 pin is a 17 blink code which translates to Crank Position Sensor Faulty. I have now received a new one of these and will replace at the end of next week. Fingers crossed, will let you know.

Another hard to identify problem within the distributor (dizzy) appears to be caused by the distributor cover inside the cap. I'm not sure if this is fitted to all models but has been reported to cause big probs when damaged with tracking issues.
 

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