SEC-Strange distributor behaviour.

[Francois]

I though I would do my car a favour and replace the original 20 year old distributor cap and also put in a new rotor.

I did replace the cap and neglected the rotor since the new one looked a bit different than the old one. The other day I replaced the old one and the car started up easily and idled at its normal 1000 rev's (which i still need to sort out). When in Park or neutral the car rev's fine. The problem comes in when you try to drive. The moment you touch the accelerator, the engine cuts out. If I lift my foot, the engine catches again and idles normally with maybe a misfire every ten seconds or so.

I put the old rotor back and everything is fine again.

I have no idea what causes this. If it was timing, would it not show this during idling too?

 

[NormanB]

I am no expert but it would appear that your 'new' rotor arm is incorrect for the dizzy cap. It is nowt to do with timing as you correctly point out.

Did you source the parts from a dealer?

Whatever, you need to go back to your supplier and get it changed.

I am also assuming that you put the dizzy cap on correctly and vacuum connections are correctly made.

Hope this is helpful, let us know how you get on.

NormanB

 

[Francois]

Thanks for the reply.

I had the rotor checked and it is the correct one for this car, where it would seem that the older one is not. That is what is so strange. Everything was connected correctly etc.

Maybe I should just go to a dealer and let them frett it out.

The older rotor is still in good condition, so I don't need to change it urgently. I was just curious about all this.

 

[talbir]

I would stress the need to buy rotor arms and caps from main dealer - replica ones are so poor in quality.

Original rotor arms will usually be a flame orange colour - replica ones will be black.

Are all the ignition leads and especially the coil lead plugged onto the cap correctly. One of the leads maybe loose or may not be attached to the right number point.

talbir

 

[Francois]

Yes everything is connected correctly, otherwise the older rotor arm would not work iether.

The two rotor arms are different in that it looks like the new one looks bigger with an extra spring in the middle. The older one is just a straight forward normal rotor arm.

I'll buy one from the dealers and see what that does.

Thanks Talbir!

 

[Andy]

Hi

It sounds like you have the wrong rotor arm. The new one with the spring in the middle. Is fitted to the early V8'S & 6cyl engines. The spring has a contact on the end acts as the engine rpm limiter as it works on centrifugal force at about 4.5k rpm. Your model the RPM limiter is housed in the fuel pump relay.


Regards

Andy @ www.mercedesservicing.com

 

[Francois]

Thanks Andy!

This makes sense. I suppose going to he dealers first and then see if there is an equivalent part somewhere else makes all the difference.