I am a bit embarrased to be asking this.....

[oldrover56]

86 County V8 with the electronic ignition module.
How do I stop ignition hash in the radio???
I thought I knew a bit about suppressing ignition noise, guess not enough.

I have supression capacitors on the coil +, ignition switch, an inline choke on the radio 12v feed, and nice new inductive plug leads.

Antenna ground is clean and ok.

Distributor cap is near new and clean, carbon brush is ok.

I have even looked under the bonnet in the dark for sparks - nothing.

I can't think of anything else to try.

The noise even wipes out the broadcast FM band and the FM cb.

Anyone had this problem and fixed it??

Help, I am sick of hearing my CD's

Thanks,
Terry

[justinc]

86 County V8 with the electronic ignition module.
How do I stop ignition hash in the radio???
I thought I knew a bit about suppressing ignition noise, guess not enough.

I have supression capacitors on the coil +, ignition switch, an inline choke on the radio 12v feed, and nice new inductive plug leads.

Antenna ground is clean and ok.

Distributor cap is near new and clean, carbon brush is ok.

I have even looked under the bonnet in the dark for sparks - nothing.

I can't think of anything else to try.

The noise even wipes out the broadcast FM band and the FM cb.

Anyone had this problem and fixed it??

Help, I am sick of hearing my CD's

Thanks,
Terry

Terry All I can suggest is that the County and Defender ALL have serious earthing issues at one time or another, I would try and fit a decent earth cable from the battery under the seat to a bolt on the seatbox. Also, remove the radio and earth it directly to the bulkhead. Also, the aerial could do with being earthed to the bulkhead, not using the guard.

Hope you find a solution:( Although with rubbish on the radio here lately I wouldn't mind 'Ultimate Santana' on repeat for a while...:D

JC

[bee utey]

Inductive leads: there are good ones and baaaad ones. My top gun leads used to give me quite a lot of interference. The bosch ones don't. Look for at least 1000 ohms per foot, better is 1500 ohms.

Antenna shield needs to be earthed at both ends. Make sure the plug and antenna ends of the lead are both firmly earthed. Make sure the antenna is electrically connected to the plug. You may need a better antenna. Keep the antenna cable run away from the wiring loom.

[oldrover56]

Thanks JC, I will have a good look at earthing everything.
I have already grounded the bonnet with copper braid, I will check a few more places.

The indictive leads are Bosch.

I think the noise is being radiated because I can hear it 20m away on a transistor radio in the house.

[bee utey]

Spark plug gap? Try running 0.8mm gap resistor plugs if you aren't already. Also rotor tip-to-contact clearance may be high. I sometimes check this by laying the rotor sideways in the cap lining up the centre of the carbon. 0.5 to 1mm is good.

Measure each plug lead individually, there have been a few crook leads come through from Bosch last year (around 1% of stock) they have unusually low resistance compared to the others. I traced odd running problems in an old Holden V8 to this problem.

Also if your tranny can pick up the noise try waving it near components under the bonnet to locate the strongest source.

[oldrover56]

Thanks bee utey,
A few good clues there, I will check dist cap & leads again.
The electronic module seems to give a very strong spark, so there must be a leakage somewhere.
If I hold the tranny within a metre of the car all stations are wiped out.
Resistive plugs I hadn't thought of, might try that.
Terry

[justinc]

Thanks bee utey,
A few good clues there, I will check dist cap & leads again.
The electronic module seems to give a very strong spark, so there must be a leakage somewhere.
If I hold the tranny within a metre of the car all stations are wiped out.
Resistive plugs I hadn't thought of, might try that.
Terry

:D:D Perhaps you ought to leave well enough alone and send the vehicle as a whole to the ADF for electronic warfare weapons developement research?...:wasntme::p

Seriously though, if the symptoms are that bad it should be easy to locate...I hope.:(

JC

[PhilipA]

OK here are a few things to look at.
1 antenna coax must be earthed at both ends and the body earth must not have potential difference to battery, so earths from Guards etc.

2 obviously the antenna input to the stereo must be well earthed and the stereo body must be earthed with no difference to the battery.

4 as stated resistor plugs which have an R in the number . Ditto bonnet.

5 Are you sure that it is ignition and not alternator? Check that the capacitor on the alternator is good.
Regards Philip A

[oldrover56]

Day off tomorrow so I am going to get into it.

Ans. so far: Antenna coax is good both ends earthed well. guard to firewall don't know, will check that.
Radios well earthed. batt well earthed, inline choke fitted in radio feeds.
Noise is Hash, not alternator whine. could be there but I can't hear it over the hash.
Resistor plugs are a possibility, I will get those if I can't find a problem.
Bonnet is grounded to the firewall with braid, I will do the guards if necessary.
Distributor rotor gap - didn't check that, we'll see.
Weapons research? Might do something with weapons if I can't fix it.....

I will let you know how I go.
Thanks,
Terry

[oldrover56]

Had a look at a few things today,

Plug leads - shortest 1.5 kOhm, longest 2.7 kOhm, rest somewhere in between. all connections to them clean and tight. I think no problem there.

Extra 2.5 kOhm across the carbon brush.

There was a lot of white corrosion on the 8 aluminium contacts, cleaned that off. Rotor tip clearance about 1/2 millimeter.

Plugs gap was ~0.8mm, cleaned and reduced to 0.5mm.

Bond guards to firewall was good (0.5 Ohm) linked with braid anyway. Bonnet already done.

Radios earth ok (3 radios, broadcast, uhf cb, vhf cfa set) all to the same firewall point. No voltage difference from there to battery with everything on.

All 3 radios now powered through the inline choke (It's an inline inductor with a cap. to ground)

FM broadcast is now readable, cb,& cfa radios ok, AM band still useless.

I am starting to believe that its the power of the ignition module. It will throw a 25mm spark to the engine if I hold the plug lead (THICK rubber gloves!!!)

I am thinking of moving the antenna down the back.

Cheers,
Terry

[oldrover56]

I am still battling this radio noise.

I think I may have found the problem.... the coil + has full 14v battery voltage on it when running, I thought these had a ballast resistor on an 8v coil?

That would certainly explain the amazing 25-30mm spark it can generate.
Coil runs very warm too.

The wiring diagram shows a ballast resistor for the conventional distributor but it is a bit vague about the electronic module version, does anyone know if it should have a ballast?

There are 3 wires from the coil to a 3 pin rubber connector but with only 2 wires connected to it - full battery voltage, and an earth. According to the previous owner there was a wiring short and it was rewired by an auto elec. so anything is possible.:eek: That explains the different wire colours anyway.

Cheers,
Terry

[PhilipA]

Usually Rovers of this vintage had a resistor wire from the ign switch to the coil which served the same purpose as a ballast resistor. It was made of stainless steel or something that was impossible to solder to. Usually white with a blue? trace.

They then had a separate normal wire from the starter solonoid to the coil to give 12 volts on cranking( or whatever the volts dropped to with the starter load).
The coil was rated at 7-8 volts or so and running was supplied with 7 -8
volts via the resistor wire.

Have you considered that you may also have a crap radio? ALL Japanese radios have poor AM sensitivity as the problem in Japan /USA etc is cross talk because there are so many stations. Some of the worse ones also have poor selectivity, and may pick up harmonics of different frequencies.
Regards Philip A

[bee utey]

I am still battling this radio noise.

I think I may have found the problem.... the coil + has full 14v battery voltage on it when running, I thought these had a ballast resistor on an 8v coil?

That would certainly explain the amazing 25-30mm spark it can generate.
Coil runs very warm too.

The wiring diagram shows a ballast resistor for the conventional distributor but it is a bit vague about the electronic module version, does anyone know if it should have a ballast?

There are 3 wires from the coil to a 3 pin rubber connector but with only 2 wires connected to it - full battery voltage, and an earth. According to the previous owner there was a wiring short and it was rewired by an auto elec. so anything is possible.:eek: That explains the different wire colours anyway.

Cheers,
Terry

There isn't a ballast resistor fitted, as the electronic switching, unlike points, doesn't switch all the way to earth. So on cranking there is still full spark. You only need 2 wires to run a coil + and - connections. Any other connector is an earthed shield (braid).

Certainly possible someone has swapped out the coil, so beg/borrow/steal an original coil and fit that instead. Coils that are not matched to the amp can have significant problems. PM me if you want a standard LR electronic coil, I think there's still a couple out in the shed I swapped out during upgrades.

[oldrover56]

PhilipA,

There is definately no ballast wire, the whole bundle from the coil to the starter solenoid were replaced by the auto elec.There may have been one once, who knows?
I think the radio is ok, the ignition hash also wipes out an FM cb and a VHF FM CFA set. I can also hear it on radios in the house 20m away.

bee utey,

Thanks for that info, sounds like a good clue.
I will remove the coil tomorrow to read the numbers on the bottom, perhaps you can tell me if they match the genuine coils you have?

Cheers,
Terry

[oldrover56]

Took photos of the bottom of the coil.
Can anyone confirm this is a genuine coil for a late 85 V8 with electronic ign. module please?
Thanks
Terry

[bee utey]

Took photos of the bottom of the coil.
Can anyone confirm this is a genuine coil for a late 85 V8 with electronic ign. module please?
Thanks
Terry
Looks like the original Lucas one. Says Lucas on the insulator? Clamped on top of the amplifier? I usually bin them as when I meet them they are dead already. They then get my Bosch ignition amp conversion as a rule. Can't help unless the later Bosch OEM coil is compatible.

[oldrover56]

Hi bee utey,

Thanks very much for that.
Yes says Lucas on the module base. Sorry second pic didn't get uploaded.
This coil works very well indeed - probably too well.
I am still a bit suspicious of the 3 wires to the coil, 1 14v, 1 earth, and the 3rd goes into the rubber 3 pin plug and stops.
This could have once been a resistor connection, I know you say it doesn't need it, I am going to connect a temporary resistor and see what happens.

I should have the electrically quietest motor in existence given the work I have done to shut it up.

My ex auto elec son in law can't figure it out either. Says Landrovers are sh*t anyway:D (Ford man)

Cheers,
Terry

[Mick_Marsh]

The extra wire could go to a capacitor. These act as short circuits of ac signal to earth. The ac signal causes radio interferance.

[oldrover56]

Well, I fixed it !!!!!.

OK I know I said that once before.

Last thing I tried was a resistor in the supply - Wouldn't start and wouldn't run. bugger.

Things done to shut it up....

New inductive plug leads.
Closed up plug gap to 0.5mm
Checked rotor gap. ok. cleaned aluminium plug lead contacts.
Checked radio grounding, ok.
Radios fed thru an inline filter.
copper braid guards to firewall, and bonnet to firewall.
Tried another coil, no difference.
Copper braid over the coil to distributor HT lead. Grounded one end.
Copper braid over ignition module leads checked grounding at coil end. ok
Checked grounding of the antenna coax both ends. ok
Tried 3 different antennas. no change.

All this made the FM band and the UHF CB usable. AM band still useless.

SO, the final fix....?
Covered the antenna coax exposed in the engine bay with copper braid, grounded to the firewall.

WOO HOO no ignition noise !!!!

FIXED at last.

Thanks for all the suggestions guys.

Cheers,
Terry

[Carslil Jim]

I had lots of noise on the am band....until I realised I had routed the aerial too close to the distributor. A quick reroute (my aerial is on the bullbar thus saving another hole in the County mudguard) and all problems fixed.

[oldrover56]

Yes I will be installing an HF radio soon and the antenna cables are going to be run well away from the engine bay.
A lesson well learned!