| Re: [GMCnet] Poor Mileage solved [message #324616 is a reply to message #324615] |
Wed, 04 October 2017 20:25   |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma:
|
Senior Member |
|
|
Emery,
We tend to think of ignition coils as indestructible, don't we? Your
experience now, my temperature-sensitive one in CO in 2017, and too many
others prove that's not true.
I had a call and subsequent photos from a GMCer this evening with something
I've never seen/heard of before: He's having surging, etc, on a new-to-him
78 Royale. Weird finding: Inside the distributor, connected between the W
(Ign) terminal and the adjacent ground screw is a diode! Have you -- or
anyone here -- ever seen/heard of that mod? I can't imagine the purpose
since about the only thing it could possibly do is blow if the distributor
was somehow subjected to reversed voltage on the Ign lead --might 'nigh
impossible.
Ken H.
On Wed, Oct 4, 2017 at 8:56 PM, Emery Stora wrote:
> I put in a rebuilt 455 engine last January. I have about 6000 miles on it
> and have only used 1/2 quart of oil and it is running great.
>
> However after installing it I was only getting about 7 miles per gallon.
>
> Upon going and returning from the GMCMI Convention at Elkhart I was
> getting closer to 6 miles per gallon.
>
> Yesterday while on I-80 in Iowa my engine stalled so I pulled over to the
> side of the highway.
> I knew that I had fuel but it would not start so I lifted the engine cover
> and checked for spark.
> There was none. I took off the distributor cap and it looked good and the
> rotor looked good so I replaced the distributor module.
> It still wouldn’t start. I also carry a spare coil with me so I took off
> the coil cover and found that the coil was so hot that I could not touch it.
> I got gloves and replaced it and reassembled the distributor and the
> engine started right up.
>
> For the next two tanks of fuel I have gotten close to 9 miles per gallon
> even towing my Tracker and going about 70 mph on the Interstate. The
> motorhome also accelerated better and idled faster.
>
> Apparently I had a dying coil and it likely was not firing the plugs all
> the time which gave me the poor mileage. Funny that the engine seemed to
> run smoothly though and I couldn’t detect a miss.
>
> I carry spares for the distributor including cap, rotor, module, coil and
> pole piece (coil beneath the module). I have used all of the spare parts
> except the coil in the 36 years that I have had the GMC but I am sure glad
> that I had a coil with me. It is usually the module that goes bad but my
> rotor, cap, and pole piece have also failed in the past while on a trip.
>
> I would have been laid up for many hours on this trip and probably would
> have had to be towed for over 100 miles if I had not carried the spare
> parts and knew how to install them.
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
