Recently installed white gauges on a 86 300E. Noticed yesterday and today, the tach seems to work only after the car has been driven for awhile. When first starting the car after sitting overnight, the tach isn't working. Then sometimes it starts to work after haven driven for half an hour or more. Did a search on this, and came up with something related to a piece on the driver's side fenderwall, sticking a cigarette butt into it?? (mostly on diesels though), does this piece and technique also apply to the 300E series?

Buttin' In...
 

Richie,

It does if you have the tach TDC sender as described. Check for the tell-tale black plastic "trash can" looking device on your driver's side inside fender. It should have a black plstic tether attached to the top of it. Just in case you do, here's the fix.

If it's there, you can unscrew it by turning it counter-clockwise, and then remove it by pulling gently upwards. Once removed you will see what looks like (and is) a diagnostic plug with about 5 contacts.

To do the repair(?) you need to remove the inner cylinder (TDC Sender) that is inside of the outer housing. Then put a styrofoam packing peanut, or other soft spongy item in the housing before putting the TDC Sender back in.

Some of these devices have, or get to have after a while, crappy contacts on the circuit board on top of the sender, and the extra "packing" helps to get them to make better contact when you screw the housing back down. Then your tach should work.

The alternative is a replacement. You can always ask PartsShop to give you a price quote for one.

Let us know how or if it works...

Re:Buttin' In
 

Thanks for the reply. This morning I looked at this piece. Once I unscrewed the trashcan looking top, there was a piece that seemed to have alot of contacts(I presume this is the piece). I didn't try to remove it(I'll try tomorrow).I'll also try the packaging peanut or what have you, and I'll post the results. Once again, thanks alot..