Re: Stumbling in the damp. Plug wires? Coil? (864Q)

[Huw Powell <audi@mediaone.net>]

> My 864Q (approx 170,000km) has developed an off-idle stumble when its wet
> out.  Mechanic says probably need plug wires (very possible as they are the
> originals) or he said a weak coil could also cause such a thing (that one
> surprised me a bit, but OK). 

could be a multitude of poor/dirty electrical connections failing in
humidity...

> And so, the questions haunting me are 1) Can
> you check a coil (or wires for that matter) to determine which it might be

yes, resistance specs in Bentley.

> 2) Wires for these suckers are more expensive than I was expecting.
> Specifically, you seem to pay a lot more for the set that comes with the
> loom, which from looking at my motor seems to be nothing more than a plastic
> tube the wires run through.  Is this thing even necessary?  

to reuse old loom cut it open cleanly along molding seam that has the
outlet holes in it, mounting clamps or zip ties close it with new wires.

> 3) To order the correct set, it seems
> I need to know if the distributor cap has "pins" or not.  Maybe if I
> describe what I've got, someone could tell me if this is a "pin" type cap.
> Basically it looks like any cap I've ever seen with towers to accept the
> wire boots, & if you peer down inside the tower, there is a small (maybe 3mm
> long) contact or "pin" I guess that receives the wire contact.  Sound like
> the "pin"style to you? 

Yes.

> 4) the coil (at least with my local supplier) is pricey.  I'm thinking, what
> is so special about this coil, would not any 12V coil do the job?  A humble
> thank you to the listers for indulging my curiosity.

Do the other stuff first - clean and silicone dielectric any connectors
you can get to.  measure wires.  check plugs, cap, rotor.  worry about
the coil last.

-- 
Huw Powell

http://www.humanspeakers.com/audi/

82 Audi Coupe; 84 4kq; 85 Coupe GT; 73 F250