I suspect the ignition coil to be the culprit for my slight hesitation on take off in my 300E. what kind of resistance values should I see from the primary/secondary of my coil?
can I test this with the primary connected?? ( not running of course ) I have an oscilloscope,, would that help at all?
your comments will be appreciated!
thanks,
Adam

I have all of this at work, but I don't have it memorized.

I have seen the coil cause a cut out upon acceleration, but not a slight hesitation.

ok,,, I just checked it. the primary end has a resistance of 0.2 ohms and the secondary is 9.02 kilohms dose this sound correct?

Adam,

The coil still may be bad even if the resistance is within range. That is not a reliable way of testing.

My wife's car, a 1989 300e, has 135k miles on it. It was having a slight rough idle problem, a slight lack of power, and would sometimes take two tries to start in the morning. Other than that, the engine ran fine.

The cap, rotor, plugs, and wires (from dealer) had been replaced 15k miles ago. So I just changed the plugs last week (Bosch H9DCO). Car ran a little bit better.

I thought the coil may be going out since it was the original unit. Instead of an OEM unit, I replaced it with an Accel "Electronic Super Coil". The Accel is a higher output with 45,000 volts. The idle has improved to a point that sometimes it is hard to tell if it is running or not. The car fires up in the morning immediately. Power is back to what it should be. My wife, who knows nothing about cars, asked me what I did to the car because it now runs great!

The Accel coil fits perfectly where the original was, on the lower side of ABS mounting bracket. You may need to drill a few mounting holes, but I made a metal bracket to allow me to use the existing mounting holes. The coil is about $50 mailorder from Jeg's.

http://www.jegs.com/photos/110140008.gif

I ordered a new cap and rotor from FastLane and will replace that this weekend just to top things off.

So for $50 buck and about the same amount of work as testing the coil, you can have a new high output coil. It made a big improvement for me. You will have to modify the coil to distributor wire. Accel provides a 8.8mm coil wire, but I just modified the existing coil wire to fit on the Accel.

-David

David,
how long have you had this coil in there??? i am very interested in your mod.
thanks!
adam

Adam,

Going on 2 weeks now. I don't see any reason why this will not last for a while without any adverse affects. The coil is designed to be used with computer controlled systems.

The coil wire modificaion is very simple. I just cut off the OEM connector on the coil wire. Then I reassembled it with the part supplied with the Accel coil as per the instructions.

I went with the Accel because I had installed one in a GMC 4X4 I had years ago. I was very happy with the results back then. Then I saw it advertised on a Turbo Volvo site. So I figured it was safe to use on a modern European ignition system. Funny thing is that they are selling the EXACT SAME COIL for $198. Go figure! Well they do include a bracket for that price. I guess the extra $148 is for the bracket and cost to remove the Accel sticker. HA! HA!

Here is a pic of the Volvo HIGH POWER SUPER COIL UPGRADE:
http://www.easternaerospace.com/auto...Super_Coil.gif

Hope this helps.

-David