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

[k7fe at aol.com]

Ray, W4BYG
Ferrite in the right places will usually solve the RFI in your vehicle computer issues.

My problems were solved with clamp-on ferrite over "every" lead in and out of my engine control computer.  Where possible, I ran the leads through the ferrite multiple times and/or used multiple clamp-on ferrites over the wiring.

My vehicle would stall when I used my homebrew 1kw amplifier.  At freeway speeds that was exciting.  Like you, I already had ferrite on the coax and other leads related to my ham gear.  My stalling problem was a result of RF from the antenna radiating into my vehicles wiring, specifically the engine control module.  My Ford has the module under the hood near the firewall.  I did shield the engine control module prior to trying ferrite and the engine still stalled when using my amplifier.

Good luck.  I hope this suggestion helps.
73,
Terry, K7FE 

 

 

 

-----Original Message-----
From: Ray <w4byg at att.net>
To: mobile-portable <mobile-portable at mailman.qth.net>
Sent: Thu, Jan 24, 2013 8:50 pm
Subject: [Mobile-Portable] HF amp causing false error codes in my auto computer.


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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