Outer Limits 4x4 Board

Chucked a new CD player in the Sierra, just a cheap MP3 one, already has an inline filter. I get really bad interference on AM when the ignition is on (even with engine stopped) but it only starts several seconds after I switch to 'Ignition'.

Is this likely to be the coil?

I bought a 20A Jaycar filter tonight that I'll chuck in that'll hopefully fix the problem but was just curious what the source of the interference is likely to be.

Off the top of my head, in my current state , I can't think what would create interference when the engine isn't turning.

EFI computer - do you have one?
Anything else electronic in the vehicle?
Did you have an AM radio before this one?

I can only suggest to start by disassembling and cleaning connections associated with stuff which is switched with your ignition. A dodgy connection causing minor arcing would explain your symptoms, but I'm far from convinced that's it.

EFI - I wish!

I've looked the thing over and I can't find any accessory that only comes on with the ignition. Everything else (GPS via cigarette lighter, radio, heater/AC fan, etc) works in the accessory switch position and creates no interference.

I did have a crap radio in there before that didn't suffer the same symptoms, but that was so old 'n crackly at all times I'm not sure I would have noticed.

Was at a wedding today and didn't get to look at it - will pull it out and rewire tomorrow if I have time. I'm rewiring the head lights and putting some spotties on anyway, so in preparation for a second battery at some stage I think I'll install a second fuseblock and wire the radio and interior light up from that anyway.

you could try pulling some fuses, you might strike lucky and find out what system the interference is coming from. does it change with revs at all?

Meh, the radio must have gotten scared at the thought of a new filter, 'cos after weeks of playing up it has been fine all day today.

Weird thing is that although I did a service last night, all I touched that was electrical in nature was the plugs, leads, dizzy and coil

Presto, when the noise was there, it was speed independent. Made no difference whether the engine was running or off, or what speed it was running at.

I'll just hope it stays gone

Electric fuel pump?????

Any solenoids controlling the purge valve of emmisions stuff??

nope and nope

Tram Tracks?

Maybe it got sick of the noise and put it's fingers in it's ears?

If it returns, describing the noise would help. Or even better, see if you can record it on you phone or something, then post it up on photobucket...

The most important question is, why the hell are you listening to AM ?

Loanrangie wrote:The most important question is, why the hell are you listening to AM ?

That's simple, exclusively For SEN and the cricket on 774 in summer.

Loanrangie wrote:The most important question is, why the hell are you listening to AM ?

News Radio

Nah listen to either CD's or 5AA - decent news service and sports show in the avo can be entertaining. Don't listen to FM much - too repetitive.

The noise was just a generic crackle - not modulated or anything.

Moph wrote:The noise was just a generic crackle - not modulated or anything.

Generic crackle is generally arcing. Loose connection, or fractured wire.

Next time it comes back with the engine off, crank up the volume, and start wiggling wires.