Author Topic: Capacitor: here is the culprit!  (Read 871 times)

philmas

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Capacitor: here is the culprit!
« on: September 30, 2024, 20:27:49 »
Hi everybody.;
I haven’t been on this forum for a while, as my car was down for several months due to a cooling problem (water pump) .
The guy I gave the car to was recommended by a friend who owns a MGB.
He took good care of the pagoda, replaced the water pump and all hoses.He called me a few days later to tell me the car would’ t start.
He initially thought some gunk could have plugged the main gas filter as the car had sit for nearly 2 years.
Finally, he stated that the culprit might be the ignition capacitor!

I really doubted this could be the issue, but nevertheless ordered a new one…and this solved the problem!
Moreover, the car drives much smoother now, particularily at low revs! I had this bucking/hesitating issue for years, and nobody ever mentioned this could be a faulty capacitor.
Moral of this story: don’t forget to check this stupid 5€ part, it is subject to die slowly, causing trouble shooting for years before final break-down!


« Last Edit: September 30, 2024, 20:33:55 by philmas »
Philippe from Paris
Euro '71 280SL manual 4sp

ctaylor738

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Re: Capacitor: here is the culprit!
« Reply #1 on: October 21, 2024, 12:02:13 »
Yep.  I had the exact situation on a 108 280se last week.  They deteriorate and ground the points, so no spark. 

Cheers,

CT
Chuck Taylor
1963 230SL #00133
1970 280SL #13027 (restored and sold)
1966 230SL #15274 (sold)
1970 280SL #14076 (sold)
Falls Church VA

ja17

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Re: Capacitor: here is the culprit!
« Reply #2 on: October 21, 2024, 15:01:36 »
Yep capacitor (condensor) problems can be hard to diagnose. The capacitor (condensor)is often good, but the mounting points for it on the distributor become corroded or loose and it loses ground (earth). It must have a good ground to operate correctly. It also can become intermittent as the grounding becomes corroded, working partially, or inconsistently. It will mimic other fuel or ignition problems. I know a person who bought a very nice 230SL for little money after a shop quoted the owner 12K to restore the fuel injection system on the non running car. I replaced the condensor  for the new owner, and the car ran fine.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

philmas

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Re: Capacitor: here is the culprit!
« Reply #3 on: October 23, 2024, 00:34:19 »
You’ re spot on!  ! None of the so called « specialists » ever diagnosed the problem. « It’s a 50years old car, you know; those mechanical FI pumps get tired with age … »
Funny enough considering this pump is almost the same model( Bosch ) that was installed on diesel engines for decades, and proved to be even more reliable than modern technologies (no electronics inside!)
Philippe from Paris
Euro '71 280SL manual 4sp

mdsalemi

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Re: Capacitor: here is the culprit!
« Reply #4 on: October 23, 2024, 17:35:56 »
There is a reason why ignition tuneup kits used to come with three parts. A set of points, a rotor for inside the distributor, and the capacitor. They should be changed regularly.

A capacitor in the ignition system is an electrolytic device that is organic. It’s not going to last forever.

Philippe I see that the MG mechanic first suspected a fuel issue! He should have remembered the following:

carburateur est un mot français qui signifie « le problème est votre système électrique ! »

« Last Edit: October 23, 2024, 17:41:44 by mdsalemi »
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
1969 280SL (USA-Spec)
Signal Red 568G w/Black Leather (Restored)
2023 Ford Maverick Lariat Hybrid "Area 51"
2023 Ford Escape Hybrid
2024 Ford Mustang Mach Ex PEV

philmas

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Re: Capacitor: here is the culprit!
« Reply #5 on: October 24, 2024, 07:14:43 »
There is a reason why ignition tuneup kits used to come with three parts. A set of points, a rotor for inside the distributor, and the capacitor. They should be changed regularly.

A capacitor in the ignition system is an electrolytic device that is organic. It’s not going to last forever.

Philippe I see that the MG mechanic first suspected a fuel issue! He should have remembered the following:

carburateur est un mot français qui signifie « le problème est votre système électrique ! »
;D
« Last Edit: October 24, 2024, 14:03:53 by Peter van Es »
Philippe from Paris
Euro '71 280SL manual 4sp