Capacitor: here is the culprit!

[philmas]

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!

[ctaylor738]

Yep.  I had the exact situation on a 108 280se last week.  They deteriorate and ground the points, so no spark. 

Cheers,

CT

[ja17]

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.

[philmas]

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!)