CB Radio interference with Holly Fuel Injection System

A

al chernoff

New member
Oct 11, 1999
737
0
0
I have the holly body, howell system. I do not seem to have a problem with the
radio. I hope somebody can offer a suggestion. I don't know if a capacitor to
ground, like we have on the old carb systems would do any good.
al

> When I use CB radio fuel injection goes haywire, have tried several cb radios
> , shielded wire direct to battery etc. Has anyone had this problem, and is
> there a solution?
>
> Thanks
> Jack in Texas
 
Jack,

Just a wild guess, but if others are using this system without interference
problems, then the first thing I would suspect would be a bad ground. Be
sure all component housings are properly grounded(preferably back to the
engine I would think) and definitely don't depend on grounding anything
through the coach body structure.

HTH,
Patrick

>
> I have the holly body, howell system. I do not seem to have
> a problem with the
> radio. I hope somebody can offer a suggestion. I don't know
> if a capacitor to
> ground, like we have on the old carb systems would do any good.
> al
>

>
> > When I use CB radio fuel injection goes haywire, have tried
> several cb radios
> > , shielded wire direct to battery etc. Has anyone had this
> problem, and is
> > there a solution?
> >
> > Thanks
> > Jack in Texas
>
 
>
> Thanks Patrick, but I have checked the ground,it is grounded to the engine,
> someone told me the radio transmitting frequency is the culbert but did not
> know any solution.


Correct, the RF is the problem, one answer is to move the antenna.
not an
easy answer on the GMC. Not many good places to mount one.
Another answer is proper shielding on the FI wiring, another hard thing
to do.
its also possible to put RF shielding on the FI control module.
 
>Thanks Patrick, but I have checked the ground,it is grounded to the engine,
>someone told me the radio transmitting frequency is the culbert but did not
>know any solution.

I'd check with someone who works on CBs. I believe there are some
axial capacitors that connect in series with the hot lead that go to
the electrical apparatus that is being interferred with and that have
a lead going to ground. These bypass some frequencies that might be
interferring. Perhaps on of our electronics people on this net might
have some input on this?

Emery Stora
77 Kingsley
Santa Fe, NM
 
> When I use CB radio fuel injection goes haywire, have tried several cb radios
> , shielded wire direct to battery etc. Has anyone had this problem, and is
> there a solution?
>
> Thanks
> Jack in Texas

======================================

I installed/serviced thousands of CBs. The hardest problem is eliminating
ignition interference. It is trial & error.
First determine if the interference is coming in on the DC line. An easy way to
do this is to connect the CB to a power source totally "removed" from the coach
(an external battery - not the coach or engine battery). Obviously if the noise
disappears, you've found the source. The battery capacitance is not always
sufficient to bypass ignition interference. A large coaxial capacitor installed
in-line w/the power lead is worth a try. Shielding the power lead (which you've
already done) might help. Re-routing the power lead might help. Pay particular
attention to the "mights"!!!).
If the noise is entering via the antenna, you're in bigger trouble. Using
shielded ignition wires might help. Wrapping the distributor w/aluminum tape
might help. Running a shielded power lead to the distributor might help. Absolute
clean "grounds" are a necessity. Using resistor type spark plugs might help.

There "ain't" no sure fire (pun intended) cure. It can take hours to trouble
shoot, & you might not succeed.

Lots of luck.


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Typically in mobile radio installations, you want both the power and ground
leads to come directly from the battery - not the engine, as you indicate here.

If you truly do have the ground tied to the engine and not the battery, the
resistance of the leads back to the battery will minimize the filtering effect
of the battery, and could produce this. I routinely run 50Watt Ham rigs in my
cars and GMC, and get no interference whatsoever - not even to the radio, and I
always wire to the battery directly.

- - Tim

> Thanks Patrick, but I have checked the ground,it is grounded to the engine,
> someone told me the radio transmitting frequency is the culbert but did not
> know any solution.
>

- --
================================================================================
Tim Dawson (tadawson) Owner/Engineer
TPC Services Bellnet: (972)-221-7385
Lewisville, Texas 75067 FAXnet: (972)-221-0393
"The world is complex. Sendmail.cf reflects this...."
 
- ----- Original Message -----
From:
To:
Sent: Thursday, May 25, 2000 11:59 PM
Subject: Re: GMC: CB Radio interference with Holly Fuel Injection System

> In a message dated 5/25/00 5:27:39 AM Mountain Daylight Time,

>
> > When I use CB radio fuel injection goes haywire, have tried several cb
> radios
> >

Reply
Where do you have the antenna? The ground plane or lack of one could be the
problem.
If you have twin truckers on the side mirrors check the ground for the
mirrors.

Chuck Sankey
Central Ohio
"Pickle 76"
 
what brand is your injection ??

gene

>When I use CB radio fuel injection goes haywire, have tried several cb
radios
>, shielded wire direct to battery etc. Has anyone had this problem, and is
>there a solution?
>
>Thanks
>Jack in Texas
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
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