[Mobile-Portable] HF amp causing false error codes in my auto computer.

[Dick Flanagan]

Try your best to shield the computer itself.  Ideally, in a grounded 
metal box.  Next best, cover it with grounded aluminum foil.

Check with the SUV manufacturer.  In the past some manufacturers have 
had RFI kits available for retrofit when the customer presents an RFI 
problem.  You are operating a federally licenses radio station and their 
vehicle is not handling it gracefully.  Approach them respectfully and 
they may be able to provide some ideas or assistance.

Dick

--
Dick Flanagan K7VC
dick at k7vc.com

On 1/24/2013 1:47 PM, Ray wrote:
> I have been running mobile off and on for close to 50 years.  I have
> dealt with many automobile RFI and power related problems.  This one has
> me a little stumped.
>
> I have a rather complex HF and VHF/UHF mobile installation.  It consists
> of an FT100D driving an Ameritron 500 watt amp, driving a 7 1/2'
> Hustler, utilizing the high power 20 meter coil.  The antenna is mounted
> on top of the car top carrier of my 2006 Toyota 4Runner. The 4Runner has
> a 4.7 liter V-8.
>
> I also run 150+ watts on 2 meters and 50 watts on 440 MHz with an Alinco
> DX635 driving a 150 watt Mirage amp on 2 meters.
>
> The equipment is mounted breadboard style on the back deck of the SUV
> along with 2- good sized batteries to act as a buffer for the heavy
> amplifier currents.  The batteries are kept replenished via a number 4
> wire attached thru 80 amp fuses on both ends, directly to the + terminal
> on the front car battery and then run under the car.
>
> The antenna is bonded at the roof.  The tail pipe is bonded at the rear
> end to the frame.  The equipment grounds on the back deck are brought
> together and then bonded to the nearest frame point (about 12" away). My
> ignition  noise is about 1 S unit or less.
>
> The HF antenna coax has about a foot and a half of #43 ferrite cores
> installed on both ends to minimize RF back into the rear areas where the
> coaxes come into the car.
>
> Over all the rig works great.  I can compete very well in many DX pile ups.
>
> My problem is occasionally when I run the HF amp, my auto computer goes
> into "protect mode" from a P2440 error code.  The car then slows down to
> about 35 MPH max until I can clear the code error.  It only does this at
> random times when the HF amp is operated.  So the problem seems to be
> RFI caused, not a defective sensor.  It does not do it at all when
> running HF barefoot at a hundred watts.  Nor does it do it on VHF or
> UHF.  The problem is much worse when I try to run the amp on 40 meters.
>
> The code reader describes the P2440 error as "Secondary Air Injector
> system valve stuck open".   I can attach the code reader and clear the
> code and the car will run fine until some other undefined time, when the
> amp will cause another similar error.
>
> Anyone have any insight as to how to protect this circuit and where it
> might be located?  I don't begin to know where to find this valve and
> any related wiring associated with it.
>
> Thank you for reading the long missive.  Your attention and learned
> comments would be appreciated.
> 73,
> Ray, W4BYG
> Cleveland, TN
>
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