RFI problem

[sleepwalker]

I have a 2006 Kenworth with a Cat engine. The radio is wired directly to the battery. I have ran several grounds in various places, moved the antenna to no avail. The RFI is coming from the wiring harness that goes from the ECM to the fuel injectors. I used a sniffer to find this out. The noise is a popping noise that is directly related to the amount of fuel applied. I have tried some ferrites on the injector wires under the rocker covers, but didn't help. When no fuel is applied there is no noise. There is no electric fuel pump. WHAT DO I DO? I'm gonna go insane listening to this crap :x :x :x :x

 

[sleepwalker]

only problem is the noise goes away when I disconnect the antenna

 

[Guest]

only problem is the noise goes away when I disconnect the antenna

That's why it's called rf noise if it came through the power lead it would'nt be a problem to correct.

 

[sleepwalker]

only problem is the noise goes away when I disconnect the antenna

That's why it's called rf noise if it came through the power lead it would'nt be a problem to correct.

tell me something I dont know

 

[sleepwalker]

I couldnt see an '06 model having a mechanical pump

All commercial diesel engines run off mechanical fuel pumps that are timed via gears in the front end of the motor.

correct!! using a piece of coax as a "sniffer" the noise is coming from the wires that run from the ecm to the connection on the head where the leads to the injectors are...without applying throttle there is no noise....only when I get on the throttle.....tried gronding, ferrite,moving antenna...noise never got any better

 

[boomer111]

Sleepwalker...Man I know how you are feeling. I am going through the same thing. Peterbilt with ACert C15 475 HP Cat, dual turbo. Great truck piece of sh-t for radio install. I have heard that their is no know cure for our problem! Just when my new Stryker was doing such a nice job into the 4 pill. If you find cure please post. I am going to talk with the tech installers at Clays tomorrow. Clay didn't know of a cure. Fingers crossed!! By the way I start at 15 lbs maniford , I get 50 when pushed. Noise maxs out at 7 S units at about 25 lbs. manifold pressure and above. Really pathic way to run a radio. I have come to be resigned to the FACT that my 30 year old radio hobby has just been slammed. No base station just the commuter and the work truck. I quess I'll have to get my 15 minutes of fame whike driving home in the commuter. Going to miss being albe to flip the switch and talk... and more importantly hear around the greater SF Bay area.

 

[boomer111]

Sleepwalker you still here?

Well, the head installer at Clays said to try and wrap alot of tun foil around the source. I tried covering the ECM unit and the plugs into the heads with 10 layers of heavy duty foil...no relieve. Next I quess I'll get some foil tape and under the harness and try wraping the entire harness from ECM to the plugs at the heads.

Ley me know of any gain you might get at your end....Thanks

I'll do the same!

 

[sleepwalker]

Boomer your problem occurs only where there is boost pressure right? I did the wrap everything trick. No help there.
I took the rocker covers of and put ferrite on every wire under there again no help.
Contact Caterpillar. I have had mine at the Cat shop and of course the service advisor looked at me like I was crazy when I told him of the problem. I have reason to believe that it MAY be the boost pressure sensor. we have 6 new trucks and have had to replace the sensor on 2. I don't know what affect that had on the radio in those trucks. I have not got any help from Cat as of yet but my local dealer sent me an email stating that he would try to tackle the problem. I know the feeling I haven't talked on the radio in my KW since I got the truck in 07-05. I have 3 S units when it occurs. I have tried grounding, moving antenna, installing ferrite all to no avail.
The boost pressure sensor is the only electrical part(that I know of) that has anything to do with Turbo Boost Pressure.I may be wrong.
Cat sent me a radio interference troubleshooting flow chart. I can send that to you if you would like. Pm me your email. Maybe we can double team Cat and get their attention!! `IMO Cat is the only one that is going to be able to fixk it. I had my truck at the Cat shop just 2 days ago and they said "Oh by the way, we didn't have time to check out that RFI problem" This was after they had the truck for 3 days!
The service advisor then sent me an email after I contacted cat saying he would need a day to find the problem. So here we go again! We will find out what the problem is.
Shoot them a message

 

[boomer111]

Message sent. Thanks again for your information.

 

[KD0FBK]

As far as I know mechanical injection pumps are a thing of the past.

That said as your boost level rises so does the "pulse width" to the injectors to dump more fuel (fuel flow and boost are directly related). ECM and injectors are know to cause lots of electrical noise.

 

[sleepwalker]

ok so give me some insight as to why the problem also occurs when the jake brake is on and boost pressure is being applied-no fuel applied...

i have had several Cat engines and this is the first to have this problem

 

[KD0FBK]

You are showing boost when the jake is on?

 

[sleepwalker]

Now one or the other turbo is making a squealing noise when the boost is at 35 psi and above....maybe a bad bearing? could this be the source of the noise?