Help Ignition Noise 1991 Caprice

ok first of all did you hook up the tuner yoursef ?did your vehicle factory system was installed with a bose system i know a 94 caprice has it but im not sure about the 91. i have a 91but a system was already installed before. go to your trunk and see if you have a box that looks like a amp. if so thats your problem you need to diconnect it. let me know did this help.

I haven't had that experience with ham radios, however I did at one point get
nasty ignition noise on the car stereo. I have a '75 Dart (V-8, of course), and
what I did, is install
8.8mm Accel Spark Plug Racing wires. They're supposed to keep more of the
electrical energy inside their heavier insulation, so you will have better RF
suppression (and more juice getting to your plugs!) Hope it helps!

Andrew
VE6SCK

Regarding ignition noise, it is hard to diagnose from a distance, but
I'll try to give a pointer or two. I think it is unusual to have much
ignition noise from a GM car, but it does happen with all vehicles from
time to time.

1. Run all power leads direct to the battery.

2. Check all installation issues (antenna mount, coax for bad connect-
ions, etc.

3. Ground the radio via shortest route to frame/body.

4. Make sure that the body has good ground to frame--might even run gnd
straps to frame at both ends.

5. Make certain antenna mount is grounded/installed correctly.

6. Ground hood and trunk on both sides near the hinges.

7. Ground muffler(s) with braided straps to frame. (Welds often do not
provide a good RF ground.

8. Remove antenna and see if noise is still present with whip off. If it
is, it is RADIATED noise.

9. If it is radiated noise, then you have to find what is radiating the
noise to the antenna. I once found that ignition noise was following
the taillight harness back to the light bulbs and radiating the noise
onto the antenna. So remove the light bulbs in the taillights and seeif
it stops.

10. I have never seen any inline filter remove ignition noise. So in-
stall caps across the alternator (for whine), and across the power leads
for electric fuel pump (if any).

11. How long has it been since the plug wires were replaced?

These are just some of the things you can do to stop the noise. It may
be something simple, or it may be hard to trace. Chevrolets are usually
not very noisy, so I tend to think there is something amiss with the
electrical system (plugs, wires, etc), or the rig/antenna is not in-
stalled properly.

Good Luck,

Jerry
K4KWH

WA2FSO,
First, lets find out if your getting the noise through
the power lead, or the antenna. To do this, while the car
is running, and your hearing the noise, disconnect the
antenna. If you still hear the noise, it's comming through
the power lead. If the noise disapears, it's comming in
through the antenna.
While plug wires may make a difference, they aren't the
only source of noise by any means. The same methods of
getting rid of noise always apply; shield, by-pass, and a
five gallon bucket of torriods. '91 usually doesn't have
a fuel pump in the tank, but it can have an electric fuel
pump. If so, by pass it with a capacitor. Try grounding
the motor block to the chassis, body panels to the chassis,
the radio/antenna to the chassis. Everything you can think
of to the chassis. The individual body panels, etc, will
make a small difference, but they are all accumulative. The
'total' can make a big difference.
One note on grounding straps. 'Braid' works fine when
it's first applied. Over a period of time, it will deteriorate
and the 'ground' will suffer. I'm not talking about tarnishing,
I mean that the weather/polutants/etc will make it 'rot'
away. Use a metal strap, such as copper flashing used around
chimneys etc. The bigger the better, within reason.
Good luck
'Doc
PS - By-passing the power lead, etc, is never a bad idea.

I have a '91 GMC 1500 truck that probably has the same hardware
as your Caprice. I get lots of noise off of the spark plug
wires. I've found that replacing the cap, rotor, plugs and all
the plug wires including the coil wire about every 50,000 miles
helps keep the noise down. It also helps to clean the contacts
on the spark plug wires periodically, especially the end that
goes in the distributor cap and ignition coil because they get
white powdery deposits that will create a spark gap. If your car
is like my truck it has a separate ignition coil. Make sure to
clean both ends of that coil wire. I found that the dealer had
neglected to do so and I got an incredible noise on the radios.
That high energy ignition will force a spark through an awful
lot of crud to keep the engine running and create a lot of RF
noise while doing it.

this in a
been a
Caprice has the
how to rid
solve problem.
Cars? any help or

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Have a friend who is using Magnecor CN wires from http://www.magnecor.com He
said it eliminated ignition noise after all other tries and wires
failed. You might have a look at their site.

Gary

Dear OM

I have read the postings here advising you of what to do. Its all good
advice. Unfortunately I had a Chevrolet Caprice 1987 with the same problem
as you and never was able to curb the ignition noise, maybe a couple of db's
that was it. My 706's blanker made no difference, in fact it was
overwhelmed.

I did all the things the others have advised and then some with no
satisfactory results. I even went so far as to buy an ANC-4 noise
eliminator and put a sense antenna directly into the engine compartment and
tried to phase the noise out but to no avail. Just a waste of $160.

I even questioned the General Motors engineers who show up at Dayton every
year in a special booth inside and they did not know what to tell me. Every
solution they suggested I had performed with negative results.

I tell you this to help you avoid going through a very frustrating
experience. These GM cars pump out 40kv spikes that no kind of suppression,
even digital, can cure. Bad design or what, I don't know and no longer
care. I would set my sites on getting another vehicle down the road and
assure myself it is inherently quiet. As for me, I mobile as a portable on
HF. As soon as I start the engine and begin to move I turn the rig off so my
blood pressure dosen't begin to boil.

The only vehicle I ever had that I could HF mobile in was a diesel. Do
yourself a favor and give up on the Chevy. Sorry to be negative but that is
my advice to you.

de Bill K2ANE

For those who are interested in information on HF mobile noise
suppression, I suggest that you check my web site below. This article
was first published in the Mobile Amateur Radio Awards Club
newsletter. I also have information on my nine-band three-antenna HF
mobile installaion.

http://www.qsl.net/ka0dxm

If you do not have WWW access, or if you have questions, drop me a
line and I will try to help.

Richard Ferguson
KA0DXM

The magnecor url given did not work. 73, David K3KY

On 17 May 2000 05:53:11 GMT, (David Sinclair)
wrote:

Yes it works fine for me, just clicked on it in the above message and
was taken right to the Magnecor wires site. It is sp[elled correctly
and the URL is correct.

I noticed I could not access a few sties last night, might have been
net loading.

Gary