Fuel Pump RFI

This subject is a little esoteric if you're not an amateur radio operator.

I have a 2006 RTL Navi. The radio is an Icom IC-7000, and the antenna is a 580RTM HiQ. Photos of the installation may be seen on my web site under the photo gallery. The URL is http:/www.k0bg.com.

The fuel pump operates like most other fuel injected vehicles. The pump runs for about 4 or 5 seconds when you first turn on the ignition. It runs continuously when the engine is running. When you turn off the key, the fuel pump continues to run until the oil pressure drops, which takes from 5 to 10 seconds.

Normally, fuel pumps are brushed electric motors which produce RFI in the form of hash. It sounds like the static you hear between stations on an AM dial.

However, in the Ridgeline (and apparently other Honda models and Toyotas), the RFI you hear is a carrier. It appears every 15 KHz. The background level of 80 and 40 mask the carrier, but on 20 and above it is annoying. Typical levels are in the sub microvolt levels, but easily heard on the IC-7000.

After talking to a Honda rep, the suggestion was to use ferrite beads. I have. In fact, after R&R the rear seat (about an hour job), installing 4 Mix 31 beads (two under and two atop the access cover to the fuel pump), the RFI is still there. Although the notch filter takes it out, I want to eliminate it.

Is there anyone out there how has had this problem and solved it? Or, perhaps one of the Honda guys who frequent these pages may have an answer.

It appears the pump either contains a piezo element, or is driven with one. In any case, it isn't an ordinary motorized pump.

Thanks for reading.

Alan Applegate, KØBG
k0bg@plateautel.net

Alan, I am going to install mt Icom 706 in my RL next spring. Thanks for posting the RFI issue. I will let you know my results. BTW de N1XXU. 73!

My Icom 208H does not have the problem. I'll install my Alinco DX-70TH and see what I get on HF.

KI4ACL

This subject is a little esoteric if you're not an amateur radio operator.

I have a 2006 RTL Navi. The radio is an Icom IC-7000, and the antenna is a 580RTM HiQ. Photos of the installation may be seen on my web site under the photo gallery. The URL is http:/www.k0bg.com.

The fuel pump operates like most other fuel injected vehicles. The pump runs for about 4 or 5 seconds when you first turn on the ignition. It runs continuously when the engine is running. When you turn off the key, the fuel pump continues to run until the oil pressure drops, which takes from 5 to 10 seconds.

Normally, fuel pumps are brushed electric motors which produce RFI in the form of hash. It sounds like the static you hear between stations on an AM dial.

However, in the Ridgeline (and apparently other Honda models and Toyotas), the RFI you hear is a carrier. It appears every 15 KHz. The background level of 80 and 40 mask the carrier, but on 20 and above it is annoying. Typical levels are in the sub microvolt levels, but easily heard on the IC-7000.

After talking to a Honda rep, the suggestion was to use ferrite beads. I have. In fact, after R&R the rear seat (about an hour job), installing 4 Mix 31 beads (two under and two atop the access cover to the fuel pump), the RFI is still there. Although the notch filter takes it out, I want to eliminate it.

Is there anyone out there how has had this problem and solved it? Or, perhaps one of the Honda guys who frequent these pages may have an answer.

It appears the pump either contains a piezo element, or is driven with one. In any case, it isn't an ordinary motorized pump.

Thanks for reading.

Alan Applegate, KØBG
k0bg@plateautel.net

Picked up my RTLnav tonight and an IC7000 is my next purchase.

I would try three avenues, a shunt cap to ground as close to the pump as possible and a wound choke instead of the ferrite beads on each wire going to the pump. Insulate these parts and wrap copper tape around the motor housing if it is not all metal or not grounded and around the filter parts. Solder a ground to the copper and attach it to the frame.

The beads are obviously not doing the job nor would I expect them to at the frequencies involved but a pair of 100 micro henry chokes and 1 uf caps should kill this beast.

Let me know what solution you come up with and maybe a photo of where you had to put the fix.

Picked up my RTLnav tonight and an IC7000 is my next purchase.

I would try three avenues, a shunt cap to ground as close to the pump as possible and a wound choke instead of the ferrite beads on each wire going to the pump. Insulate these parts and wrap copper tape around the motor housing if it is not all metal or not grounded and around the filter parts. Solder a ground to the copper and attach it to the frame.

The beads are obviously not doing the job nor would I expect them to at the frequencies involved but a pair of 100 micro henry chokes and 1 uf caps should kill this beast.

Let me know what solution you come up with and maybe a photo of where you had to put the fix.

Note to self: Remember these guys if I need help with an electrical problem... lol :cool:

Although I've got little more than a clue what it is you guys are discussing... I'm glad you're members of the ROC! :D

As a "wireless" homeowner, I've dealt with automation problems of the rf variety, so I think I know your frustration.

Sorry I can't help with your noise problem, but I AM interested in the fix, when you find it.

Heck... I was under the impression that the RL's fuel pump was in the tank...

Good luck,
Pug

p.s. k0bg... I checked-out your site. Nice!

I suspect you're not going to hear it on an FM radio as it is a AM carrier, albeit not modulated. If you know what to listen for, you can hear the carrier in the AM radio spectrum.

One fact that leads me to the conclusion that it isn't a motor like other fuel pumps, is the pictorial of it in the schematics is different than one for a fan motor or power seat motor.

The carrier can be heard as can the pump, by removing the gas cap and listening to both. They coincide, and removing the relay also confirms the scenario.

The pump is in the tank, but the tank is plastic. The pump housing, which is also the fuel level device, is grounded by a short ground lead.

If the carrier is radiated by the pump itself, bypassing the low impedance power lead isn't going to suppress the emitted RFI.

It is my hope to be able to talk with a Honda engineer this next Thursday when he visits the dealer.

More later, and I hope it includes a FIX!

Alan, KØBG
www.k0bg.com

Here's a small update. After checking with the dealer, and speaking to a couple of well-informed mechanics, I called and opened a Case with American Honda. After a couple of hitches, they essentially told me anything. Fact is, at this juncture I know more than they do.

Today, I wrote a letter to their Torrance, CA CS Dept. asking the them to reopen the case, and escalate it up the ladder.

I took a copy of the letter to my dealer, and they will be asking the area rep for help too.

Sooner or later, I'll get this resolved.

If you think that Hondas are RFI noisy, you should see the photos posted on my web site's Photo Gallery of VE3XKD's Prius.

Alan, KØBG
www.k0bg.com