Engine R.P.M. tied to dimmer switch

Probably could be considered quasi-normal

I believe it indicates that one of the "ground" connections to (or within) your instrument cluster isn't so great. How much of a output change are you talking about -- half a needle width, 1/4 of the total motion, or something else?

 

My 84 Mondial does something similar, when I put the lights on the oil pressure, temp and fuel all increase. Works well if I am running low on fuel, just switch lights on and have an extra couple of galls .............

 

Philip,
You may have solved the energy crisis !

 

Same here--I noticed that my 308 always ran hotter at night! As soon as the lights are on the readings go up a few degrees--wierd.

 

Sounds like a bad ground; I had the exact same condition.

Try doing a 'tap test' on the dash to locate the ground, that's how I found where the loose ground was located.

 

Leads me to wonder,, Which is the correct reading ?

 

i have higher oil pressure when my headlights are on too.
308 gts carb

 

All of my readings read LOWER when I switch on the lights. Mine must be backwards.

 

OH YES !!
LOL

 

REMEMBER:


As the owner of an Italian vehicle, you have undoubtedly found that,
from time to time, the thing defies all known laws of Physics.
Distinguished researchers from all over the world have spent entire
lives trying to understand such phenomena. Recently, the Six Laws of
Italian Sports Cars were discovered, thus reducing most owners'
dependency on sorcerers and prayer, to keep such cars running.

Careless application of these laws to any individual auto may fix the
problems of the moment, but cause hives or allergies in said owners.


LAW 3) THE LAW OF ELECTRICAL CHAOS
"All Italian Sports Cars shall be wired at the Factory by a
cross-eyed, color-blind worker, using whatever supplies are within
reach. All wires shall change color-code at least once between energy
source and component. all grounds shall be partially insulated." This
tends to guarantee that the owner of such vehicles will eventually be
intimately familiar with its electrical system, since he will need to
trace out each wire, then rewrite his Official Schematic, which will
differ from all others in at least one area.

 

Aside from that bad ground thing; if you want your instruments as bright as possible (besides replacing the bulbs) why don't you just bypass the rheostat altogether? It's just another unnecessary load between your alt/battery and the lights. It's a 15 minute job. No big deal.

 

As the owner of an Italian vehicle, you have undoubtedly found that,
from time to time, the thing defies all known laws of Physics.
Distinguished researchers from all over the world have spent entire
lives trying to understand such phenomena. Recently, the Six Laws of
Italian Sports Cars were discovered, thus reducing most owners'
dependency on sorcerers and prayer, to keep such cars running.

Careless application of these laws to any individual auto may fix the
problems of the moment, but cause hives or allergies in said owners.


1) THE LAW OF PLEASING DESIGN WHERE IT REALLY DOESN'T MATTER
"The inside of cam covers or other relatively innocuous areas, shall
be laced with buttresses, cross-bracing and all manner of esoteric
stiffness-with-lightness design, while something like connecting rods
shall self-destruct at redline plus 1.0 rpm due to a basic lack of
strength." An example of this Law is the stunningly beautiful
Lamborghini or Ferrari V-12's of the late '60's. They were famous for
wearing out all four camshafts in 10,000 miles or less. The cam's
metal appeared to be recycled coat hangers, which coincidentally are
still in short supply in Italy.


2) THE LAW OF NON-FUNCTIONAL APPARATUS
"All Italian Sports Cars, regardless of age, shall have at least one
system or component which does not work, and cannot be repaired. Such
a part shall never be mentioned in the Official Shop Manual, although
there may be an out-of-focus picture shown." It goes without saying
that such parts should never under any circumstances be removed, lest
the natural balance of the car be upset.


3)THE LAW OF ELECTRICAL CHAOS
"All Italian Sports Cars shall be wired at the Factory by a
cross-eyed, color-blind worker, using whatever supplies are within
reach. All wires shall change color-code at least once between energy
source and component. all grounds shall be partially insulated." This
tends to guarantee that the owner of such vehicles will eventually be
intimately familiar with its electrical system, since he will need to
trace out each wire, then rewrite his Official Schematic, which will
differ from all others in at least one area.


4)THE LAW OF PERSONAL ABUSE
"The more an Italian auto breaks down, the more endearing it becomes
to its increasingly irrational owner." For example, you purchase an
Italian Sports car, for all the money you ever hoped to earn, and
receive a ticket for air pollution on the way home from the dealer due
to the vast clouds of smoke that follow you. Several return trips to
said dealer, accompanied by your rapidly dwindling cash reserves,
cures the smoking. But now, the engine sounds like a food processor
full of ball-bearings. After replacing every component in the car,
including the radio speakers, the noise vanishes and is replaced by an
odor reminiscent of a major fire in a goat-hair mattress factory. You
still keep trying, God help you.


5)THE LAW OF UNAVAILABLE PARTS
"All parts of an Italian sports car shall be made of a material that
is available in inverse proportion to its operating half-life." Thus,
the speedometer hold-down screws are made of grade 8 cold rolled
steel, while the valves are of fabricated Unobtanium, made only at
midnight by an old man with a pointy hat covered with moons and stars.
Such parts will be backordered during the design phase of the car, and
will remain so forever. Bribes, pleading and threats will be ignored.


6)THE LAW OF CRYPTIC INSTRUCTIONS
"Any official publications dealing with repair, maintenance or
operations of an Italian sports car, shall be written such that every
fourth word is incomprehensible to the average American. In the event
that a random sentence is understandable, its information shall be
wrong." This is also known as flat-tire English, where a sentence
flows along nicely, then-Kaboom!

 

"Engine R.P.M. tied to dimmer switch "

Zebra308,
Be sure not to turn the dimmer switch to 'high' as you may
over rev the engine!

 

I had a similar problem with my '84 Mondial QV, plus an added twist -- when you stepped on the brake or hit the turn signal, the radio would fade out for a moment. You can only imagine what it was like listening to the radio in stop and go traffic.

The cure? The ground from the battery to the frame. The battery cable went to an on/off switch, which in turn was connected to the frame by a woven ground strap. The switch was completely corroded and useless and the ground strap disintegrated when I took it off. I rewired the ground cable directly from the battery to the frame, cleaning up all of the connection points, and Miracle!.... the fading radio and variable gauge problem disappeared. It also solved my intermittent starting problem as well.

Steve, Excellent Laws of Italian Cars! May I have permission to post them to a Jaguar list? I've seen something similar for British cars, but this one is MUCH better.

Regards,
Steve

 

Steve

Those laws are great and so appropos. I have recently decided to leave my passenger power window in non-operating mode, as I have discovered that each time I fix something, something new goes wrong.

Therefore, by not fixing the window (hey, its a spider anyway) I am not providing any opportunity for something else to fail, and more importantly I won't get that false sense of OK-ness about the car being "all fixed now...".

I am going to try that light dimmer thing, too, when I first start the car - if I can get the oil temp up sooner I can start using 2nd gear....

Cheers
Kevin

 

Go for it, nJoy