91 Civic corrosion of rotor button

Hello all,

I was helping a friend recently with his 91 civic sedan (D15 engine code I
think). The car wouldn't start so we went through the ususal things and
finally arrived at the distributor. The contacts were corroded and we
cleaned them as a temporary fix. Car started right up. I suggested he
repalce the plugs, wires, cap and rotor button as a precaution. The cap and
rotor contacts were badly corroded. A couple of days later he had replaced
everything and the car ran fine for about three or four months.

Yesterday he called me because the car wouldn't start again. Again we
pulled the distributor cap to find that the new rotor button and contacts on
the cap were corroded. Though not as bad as the first time. Still they
were corroded bad enough that the car wouldn't start.

Why would these parts corrode that fast? We do live in a high-humidity
environment, but his is the only example of this I've seen. Is there some
sort of seal on the distributor cap that we missed? There wasn't one on it
to begin with, but that could have been ham-fisted by a previous owner.

This one is real a head scratcher for me. Any suggestions are appreciated
or advice would be greatly appreciated.

Thanks

Mike

 

Are you using OEM parts or aftermarket? I'll bet it's aftermarket.

How worn are the plugs? What's the gap?

Is the resistance of the wires within spec for your system?

 

The parts are aftermarket I'm sure. This time we didn't actually check the
plugs. There was not enough time he was in a parking lot and trying to get
back home. Last time the plugs were very well worn. The resistance of the
plug wires were in spec (new ones). Knowing him he probably skipped
checking the gap when he installed the new plugs. (I'll be sure and whack
him in the head for that one).

Are you thinking that something is causing to much current draw and causing
the excess corrosion? I was sort of thinking along these lines.

Thanks a million for a fast reply.

D'Funk

 

Just because they're new does not mean they are in spec. If resistance is
lower than the OEM ones, you can burn out other components with the excess
current. Aftermarket wires sometimes have lower resistance than OEM,
supposedly for "performance".
Here's one horror story:
http://www.tegger.com/hondafaq/badsecondary/index.html

The plug gap would only matter if it was seriously out, like double the
specified gap, or if an electrode had broken off, and you'd notice that.

I'm thinking your parts have insufficent resistance and possibly poor fit
as well.

 

Yes I see were you are going. Something is definitely out of whack. About
the plug wires I did actually check the new ones while my friend was
cleaning the rotor button. I don't remember the exact readings but the
longest was about 10K ohms and they dropped by about 10 percent per wire.
The shortest (num. 4 wire) was about 7K ohms. (I think.) I'm not sure what
factory spec is I don't have and FSM for this particular car, but that would
seem about right. The only thing we haven't removed and examined
physically is the coil. He'll call again in a few weeks and when that
happens I'll remove the coil and check for the proper fit with the
aftermarket cap.

By the way thanks again for all the free advice and the great web sight you
maintain. I've now book marked it!!

D'Funk

 

25K ohms at 70F.

Uh-oh. Are these "performance" wires?

 

No they were not "perofrmance" wires but they were probably the cheapest he
could find!! When he calls me I'll recheck them just to make sure my memory
and multimeter were working correctly. But I'll bet that's what it is.
Good Call.

Thanks

D'Funk