FUEL PUMP RFI ( ham radio related)

Know whats funny, that POS ford transit I have for work, had the exact same setup in it and it was quiet. Not a single peep of hash and trash........

 

that is a new video to me.
do you have a scope? can you probe the signals going to the pump?

 

I have an old tectronix up laying in my garage; but the last time I used it; the controls were so scratchy I can’t remember if I could even calibrate it.

 

Depending on how you hold your phone, you pinky can block the mic.

 

too many scopes here
it would be interesting to see if electrically 14MHz is on the wires going to the pump.
not what you want to hear...but it looks like it might be easy...wrap the ECU in some foil and see
if it gets RF quieter. no more ideas coming to mind.

this post may not be a total bust....
https://discussions.apple.com/thread/251246552

 

btw: meant to ask earlier.
i have family in scranton/w-b area and they had some flooding with ida.
are you and truck unscathed?

 

lol. i've never done that. jk.

 

Wait. I missed the 14MHZ earlier. That's way too high to be the fundamental PWM frequency. Are you seeing a harmonic of the actual PWM? I would have expected something in the low double or single KHz not MHz

 

I just called my brushless expert and he confirms there is nothing in the motor that could be responsible for 14MHz.
And the PWM freq should be in the KHz range (as Trail Limo also suggests).
His (and my) suggestion is to wrap the ECU in a foil or a can but it must be STEEL...no aluminum.
It must be magnetically permeable. Ideal is Mu-metal but first things first.
If a can, poke some holes in the steel cover to get the wires out. This is an experiment. If it gets RF quieter
you can try to make it perfect. If not...at a loss here. Fingers crossed.

Edit: do not ground the can or foil.

 

A point of clarity here. Just because the PWM is in the KHz, doesn't mean the controller or motor, or cabling is not radiating the noise. It's possible that the 14MHz is a harmonic of the PWM frequency.

 

Agree..I understood, but 14MHz is several orders away from what one would expect to be a PWM freq. That would mean the PWM RFI is MASSIVE in the fundamental freq.
IFF 14MHz is actually the fundamental RFI freq, I am thinking an oscillator in the ECU.

BTW: in the video that was just posted (new to me anyway) where the ECU is disconnected from the pump...and the 14MHz is still there...kind of tells
me it is the ECU and not the pump since the pump is unlikely to be generating 14MHz on its own. I think OP drew the opposite conclusion...unless i misunderstand.

Speculation gets deeper and deeper. My money is on the ECU (fortunately it is not real money ). Only one way to find out. If it is the ECU, it is possibly easily suppressible. The pump would be a bitch.


EDIT: on the other hand, I don't see any full spectrum display from say 0Hz to 15MHz in the videos. I trust OP is not just showing what he is getting thru his ham rig and ignoring lower freq RFI....possibly REALLY strong RFI.
Getting a sinking feeling...Are there RFI peaks between 0Hz and 15MHz? can you make another video to show that full spectrum rather than narrowly centered on 14MHz?

 

Yeah we are good. The eastern part of Montgomery County got hammered with the tornado and flooding , along with parts of Philly , and the usual spots at low elevation got flooded around here.
We are all good, thanks for asking..

 

I did clamp on about 7-mix31 ferrites into the lines leaving the ecu with no change and also the harness entering the ECU, so it’s not radiating,IMOP from the ECU. In the last video , the RFI is not there when the truck is running with the residual fuel in the lines.

this video showed a spectrum sweep of 4-52MHZ …..


https://youtu.be/aCzK2s_Bp5c

 

Can you do a sweep of the KHz range? 1-30 KHz should be sufficient. Or better yet a sweep fro. Ohz to 15mhz as pdxtaco suggested?

 

Agreed. 14mhz being an oscillator would make a lot more sense... Would also mean that Toyota really messed up if it's spewing that much oscillator noise.

 

Not on that meter I can’t, I’ll dig out my cheap ass SA Amd see what it looks like tonight possibly

 

riddle me this… I hear your oscillation theory, but that would have been eliminated when I unplugged the output of the ECU that feeds the fuel pump.

Power and signal to the unit would have still been there , it would still be generating the signals it just wouldn’t be being fed to the pump and the RFI would have still been present.
It also eliminated the issue of it radiating from the ECU with the Ferrites clamped onto both inputs and outputs.

 

bhi noise reduction pricey but they work very well.

 

All that does is filter the audio output, does nothing to eliminate the RF issues.

Not something I’m willing to fiddle fuck with while driving, especially when the rig it’s self has numerous IF filtering and DSP built in. It’s pointless in my opinion to try and dig something out of the noise floor when the local RFI is well above s9- 20 over locally. That would work well for adjacent QRM , static crashes etc but not in this case.

 

If it was an oscillator, it would be the first time I have seen one spewing that much noise. I would be far more suspect of the PWM than the oscillator.

The only reason to bring up the oscillator is due to the fact that the noise is in the MHz. No PWM motor controller operates up there. Again, you can still be seeing a harmonic. The best way to prove that is to look at the lower frequencies.