Solving HF interference from the TD5 motor

[mousie]

Folks

I thought I'd have a go at reducing or eliminating the known TD5 interference is an issue with a few members and I finally found a part solution and to show you the level of attempt I went to so I can use the HF on the move.

I run the FT857D remote roof mounted with the Codan D series autotune mounted at the rear of the vehicle. The main body is within the inside RD luggage compartment. Proper cabling and no RFI through the DC or accessories to drive the autotune.

First up earth (straps).

1. Rear exhaust to towbar mount to chassis.
2. Left and right bonnet to outer guards.
3. Brake booster to RH guard
4. Engine tappet cover to engine to RD inner guard.
5. BCU (behind passenger glovebox) earth feed striped to introduce braid to left guard/firewall.
5. Air conditioning compressor earth to Engine.
6. Various locations with either a 1uF and 4700uF cap without success.
7. Rear door to Body.

So what did the above achieve, very little change!

Next stop, back to the Injector loom with earthing and ferrite beads at ECU. Beads applied to:

1. two on fuel line harness at entry point to pump.
2. the 4 locations as described in another thread here. Air Comp, Injector input plug, two at connector at ECU.
3. BCU yellow plug.

Then got serious and pulled apart the internal engine injector loom (again) and put in ferrites by 5 inside each connector to the injector itself. No change!!! and given I didn't know the strength of the material, loom ferrite removed as didn't want this material working the engine over.

Finally, ripped out the injector wiring harness from injector engine plug to ECU and applied a full shield. The shield does not work on its own unless properly earthed and I did have a lot of success when applied further earth straps to engine and ecu area. Noise is still present and energy is now 1/2 to 3/4 down in strength so the AGC when set to auto does not activate on the injector noise.

Whilst I have not had total success I have reduced from an s3-5 (no AGC) to no reading and just a slight sound. Furthermore, For I seem to be able to change the frequency of the noise and is no longer broadband accross the a band area by moving the earth braid along the injector earth and clamping down.

To my surprise I found in my case the rear demister lines act as a radiator of the RFI and directs into the antenna and after further work on the rear, the only solution was to disconnect the two. Earth line is the Left Rear so this may be a solution for some.

My next challenge is perhaps a final braiding of the remaining ecu and took note of that grey connector as per the other thread as maybe an attempt.

Side issue I found oil in that connector and within the two snap in connectors under the fuse cover from the previous leak from the past owner.
I hope this helps some and perhaps the lesson here is give up!

Here is my setup and sellcall is a modified Codan 8422 that plugs in when required.

[mousie]

And the final two pics of the setup, the red push switch activates the autotune and light stays on to indicate tuning. Speaker under the drivers seat.

[Lotz-A-Landies]

Mousie

Common rail diesels are almost as bad a petrol engines for RFI (EMI) on HF, it seems that it is not a priority or even a consideration with most/all manufacturers. Another source of EMI is the Waeco fridges, although they have been improving.

The first place I would have gone would have been shielding the loom. You have done an exceptional job threading the shielding over the looms, most people merely use the shielding wrap, ferrites and grounding.

The most important issue in grounding are checking that your body and chassis have good grounds. This often means removing the OEM straps and abraiding the surface and re-attaching and then (as you said) place additional ground straps between the bonnet and body/chassis then rear door and body/chassis. After those the reductions in EMI will be minimal but understanding that a good ground between any metal panel and the chassis minimises the potential of EMI on HF.

[Bundalene]

Hi, I have had a Codan 8528 on our TD5 Series2 Disco for years with no RF interference, however, our auto tune aerial is on the bullbar. Our Codan was mounted behind the cubby with a remote aerial driver immediately under. I ran the aerial driver multi core and the 50 ohm coax directly to the arial, right away from any other cables. Also I ran a large earth (10 sq mm) from the aerial base directly back to the battery and another to the radio -ve supply.

I must sympathise with your dilemma as I have had some experience trying to reduce the EMI from HF radios on a truck a few years ago, it played havoc with the injectors.

The other thing which really upsets the Codan is the early WAECO fridge. A friend had one of these fridges and if we parked within 20 meters of his car, the HF would go crazy whenever the fridge ran.

Our Fridge is a Trailblazer and we get no interference at all, ever though both the fridges supposedly use the same controller!

I have now transferred the same Codan to our TD5 Defender and it works a treat.

Our call sign is VJN49.

Erich

[mousie]

I forgot to mention in another thread I was having difficulty with getting the nanocom to talk to the BCU (engine part fine and reliable as always for reading clearing) so I have to remove the yellow plug to the BCU with only ignition on to read clear with no worries.

So I have something further like a dirty connection and presently I'll have another go to solve this if possible. Just do not know where to look at this stage! Perhaps Christmas first and wait for the next rainy day.

I'll work on following the yellow connector wires to their destination. And yes, appears to be isolated landrovers and I just have one. fortunately I have the basic one which is enough electronics to digest.

Cheers Geoff

[Blknight.aus]

try this.

Remove the ECU and set it up on a floating earth plate then run a dedicated earth to the body with a ferrite choke on it.

I've always had a sneaking feeling that the noise source of the TD5 is the Amps in the ECU spiking back into the main earth.

[mousie]

Will give this a go after the new year and post results and pics (if necessary). I agree with you that the source in my case is perhaps the ECU and not the injector. Already ripped the cover off to work it over, t not destroy?

Cheers

[scott oz]

mousie,

Interesting thread. (I’ve got a 2001 TD5 110)

Not being too electrical (read none) but my understanding is that all currents emit electro magnetic interference (EMI) to some level.

Clearly you’ve gone to extreme lengths to eliminate as much of the EMI as possible. I’m curious or rather have a question. Improving the grounding to the chasse, motor etc wouldn’t it be superior to take all grounding directly back to the battery?

My thinking is that grounding to the chasse, motor, body potentially provides a larger electro magnetic field by using the chasse/body etc as a return to the battery even if it is extremely small/low.

By providing a dedicated return at each point to the battery, admittedly there would be a few, you reduce the overall size of the EMI field by limiting current return to dedicated return lines?

I’ve already started on mine by running a dedicated earth line the length of the vehicle, for the auxiliary battery for all components using the auxiliary batter and will extend the “standard” earth line as well.

I’m then going to work my way through the vehicle taking all “earthing” back to the appropriate dedicated line.

Would be interested in your comments.

[mousie]

I started out with dedicated heavy duty 80 OFC cabling to the rear and isolated to a rear battery as well and no earthing outside the long run. From there started the journey as your suggestion I always start with and ensure the radio chassis and ant are properly grounded. I've disconnected all and connected my KIenwood PS-53 power supply direct with no remote cabling from the back and presto, all the same and can easily prove all RFI entering the antenna itself. From there shielding to see if I can trap a possible radiating element. Did the sniffer trick only to prove strong signal from front of block to ECU. Left BCU and RH fuse panel. So independent battery source is the key to prove this so this might be easy for you to get a second battery. I found the ferrites useless really with not one doing a decent job and mind you you need the right material to be picky. With beads not working and heaving sheidling I can only assume the current level possibly 80-100volts and at 8amps (on web advice on amps and not sure about this) is the sheer current is just radiating from the injector itself (rememember i put 5 beads at the injector itself of a reliable brand) with no difference. At the end of the day, I can no drive and talk with the a few custom settings and the energy level is far reduced so as to allow the real signal to be present.

I'm at the end of an easy fix for this, and shielding was not as hard with a bit of spare time and a little at a time.
Cheers Geoff

[Sleepy]

Interesting thread.

Makes me think, perhaps another reason why the military stuck with the tdi :angel: