Engine Spark Ticking Through Radio

Joined
Nov 9, 2012
Messages
12,439
Location
Olathe, KS, USA
96 Land Cruiser
Alpine Head unit, about 5 years old

I have recently developed a tick through the radio while driving, and mostly noticeable at stop signs.

On my Studebaker, there's a capacitor looking thing called a radio suppressor on the firewall, tied into the ignition.

Is there something similar on the LC? I have not had an opportunity to chase it through the FSM, and electrical is not my strongest point, but I can work through it with time.

Where should I look first?

I did notice it a few weeks after I replaced the plugs, wires, cap and rotor (All Toyota of course)

Could I have bumped something loose? I cannot find any plug wires that are not seated properly.

What's really weird is that I only notice it on radio stations away from where I live, and usually in the 95.5 to 98.5 frequency.

Is it my head gasket?
 

Irish Reiver

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Definitely your head gasket :)
I would have thought that a modern radio would have had sufficient built in suppression. The noise is normally caused by a spark - something is shorting or something is not grounded correctly.
If you have a small hand held radio, flip it to MW band tune to a frequency with no stations. You can use the radio to find the locale of the problem. My guess is that you have a plug lead that isn't on quite right.
 
Joined
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Chattanooga, TN
The radio to search is a great idea and I agree that an unseated plug wire is a likely candidate in this situation. Just in case you want more ideas here are some from my misfire chasing experiences.

An easy want to try to find the spark leak is to let the engine idle when it's very dark under hood and then mist the ignition wires with water. If the arcing is happening out where it's accessible you'll see the traces of light with the added water or possibly even without. I've found failed wire insulation this way and it also helps identify any places where wires need to be distanced from surrounding metal, etc. It could be hard to see the problem with this method if the arcing is near the bottom of the plug tubes or in the dist. cap.

I doubt it applies here thanks to the new parts but cleaning / degreasing can really help cut down on misfires because if there's a conductive film it could be encouraging stray flow. This is most often a problem on the insulator section of spark plugs themselves in my experience so new/clean plugs are not suspect unless one/more got dirty pre/during install somehow.

How confident are you of the plug gaps? I've found that if the gap is too large that the balance is thrown off such that the gap is no longer the path of least resistance and the spark will find a different place to happen away from the spark plug partially or completely. When plugs are on the edge the addition of high humidity or rich fuel mixture can be enough to tip the scales and cause a misfire. If you find one wire/circuit that is causing this problem you may want to inspect the spark plug as it could be high in terms of resistance and essentially stopping the electron flow from the path you want it on. A loose or unseated plug wire will similarly add resistance to a circuit causing a misfire elsewhere and can also create another place for a spark to happen even if the rest of the circuit remains misfire free.

If this is a misfire it's likely that resistance is either too low where you don't want it or too high at the electrode/air gap where you want the spark to happen, unless you've modified the circuit with a break (loose/broken wire).

Good luck finding that annoying misfire!
 
Joined
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Too much dielectric grease on the ignition wires, spilling onto the metal-metal contacts (rather than remaining just on the rubber seals), and thereby creating excess resistance?
Notice anything odd with your tachometer ?
 
Joined
Dec 10, 2007
Messages
8,365
Same here, turned out to be loose plug wire to one of the distributor plug towers which was arching and turning the aluminum inside the tower to dust. IIRC it was more noticeable (radio on) in the AM frequencies. A new headgasket will probably fix the problem.
 
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Well, I did the visual in the dark out on a lonely stretch of highway about 10:30 at night and couldn't see any sparking.

I also pushed on all my plug wires into the cap and felt no new clicking or had anything push in further.

I also wiggled all the wires while running in the dark to either create a spark, cause a stumble, or shock my ass and knock me out in the middle of the road. No joy on any of that.

My.plug tube seals are not leaking, at least not as evidenced from changing the plug wires 8000 miles ago. Doesn't mean it's not doing it now after moving things during the plug change.

Thanks for the help!

I'll keep listening and looking for possibilities and advise if I find it.
 

smritte

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This is something I had to deal with in the shop forever. Remember AM radio? On FM most of the work was done on aftermarket radios or AM CB's. If you have a CB, do you hear the noise there? AM is more susceptible than FM. I can barely hear my ignition with the squelch all the way down. If its real noticeable, you have an ignition problem. If you can get another "like" cruiser to compare noise on CB, that will give you a baseline.

I have found, there are few aftermarket radios with good noise suppression. Factory radios are way better but don't tend to have features we need or the sound quality we want. I run Alpines for a variety of reasons but not for their suppression. "If" your ignition is in good shape, you next look to antenna connections. Crappy adapters come loose. The antenna and mount need to be inspected also. Think of it like your setting up a Ham radio. Your just not transmitting.
Next is inline filter on positive and negative leads. This would mean either you missed an ignition item or your radio's filter decided to go bad.
I would do positive first and see how that goes.
 

YvesNL

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Check radio Ground, if the ground is bad it will most likely ground through the antenna ground.
I've had two mates with this problem, after repairing Ground issue the noise was gone.

Easy to check, unplug Antenna and measure from casing of radio to body of car (or negative battery terminal).
Once you unplug Ground there shouldn't be a connection anymore (if antenna is unplugged).

I've also solved noise issues by using some ferrite around the positive and negative power supply wires or by placing decoupling capacitors near or in the radio.

Worst case in a mate's car I installed an isolated 12V-12V DC-DC converter. Expensive but almost guaranteed to solve the issue.
 
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This is something I had to deal with in the shop forever. Remember AM radio? On FM most of the work was done on aftermarket radios or AM CB's. If you have a CB, do you hear the noise there? AM is more susceptible than FM. I can barely hear my ignition with the squelch all the way down. If its real noticeable, you have an ignition problem. If you can get another "like" cruiser to compare noise on CB, that will give you a baseline.

I have found, there are few aftermarket radios with good noise suppression. Factory radios are way better but don't tend to have features we need or the sound quality we want. I run Alpines for a variety of reasons but not for their suppression. "If" your ignition is in good shape, you next look to antenna connections. Crappy adapters come loose. The antenna and mount need to be inspected also. Think of it like your setting up a Ham radio. Your just not transmitting.
Next is inline filter on positive and negative leads. This would mean either you missed an ignition item or your radio's filter decided to go bad.
I would do positive first and see how that goes.


I have not tried it with the CB, but I will that's a great idea! Thanks!

Yes, I know AM radio well (Studebaker) and why there is radio suppression on those.

Check radio Ground, if the ground is bad it will most likely ground through the antenna ground.
I've had two mates with this problem, after repairing Ground issue the noise was gone.

Easy to check, unplug Antenna and measure from casing of radio to body of car (or negative battery terminal).
Once you unplug Ground there shouldn't be a connection anymore (if antenna is unplugged).

I've also solved noise issues by using some ferrite around the positive and negative power supply wires or by placing decoupling capacitors near or in the radio.

Worst case in a mate's car I installed an isolated 12V-12V DC-DC converter. Expensive but almost guaranteed to solve the issue.

The fact that you brought up grounding, I may have a deeper issue or maybe one or more of my ground wires is a problem.

I have noticed that If I am driving at night on a very dark road with all my driving lights on as well as my high-beams, if I trigger the window switch while the window is already in the "UP" position, my lights get BRIGHTER as if they are searching for a better ground. I would have expected them to get dimmer, as if there was a power draw.

Maybe both of these are related.

Keep the insights coming!

I've got a bunch of windshield time coming up this week, so I'll keep looking!
 
Joined
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Messages
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Olathe, KS, USA
This is something I had to deal with in the shop forever. Remember AM radio? On FM most of the work was done on aftermarket radios or AM CB's. If you have a CB, do you hear the noise there? AM is more susceptible than FM. I can barely hear my ignition with the squelch all the way down. If its real noticeable, you have an ignition problem. If you can get another "like" cruiser to compare noise on CB, that will give you a baseline.

I have found, there are few aftermarket radios with good noise suppression. Factory radios are way better but don't tend to have features we need or the sound quality we want. I run Alpines for a variety of reasons but not for their suppression. "If" your ignition is in good shape, you next look to antenna connections. Crappy adapters come loose. The antenna and mount need to be inspected also. Think of it like your setting up a Ham radio. Your just not transmitting.
Next is inline filter on positive and negative leads. This would mean either you missed an ignition item or your radio's filter decided to go bad.
I would do positive first and see how that goes.
Well, I had an opportunity to check to see if I could hear the tick through the CB. Sure enough, I can.

So, I will start going through ground cables and refreshing them.

Thanks for the insight folks! I will continue to post as I work through the issues until I have a solution!
 

LandLocked93

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Assuming you used a wire harness kit...
...sever the Alpine-side neg wire from harness-side neg wire...
then run a separate wire between Alpine-side neg and batt neg terminal. Re-eval for noise.
If no more noise, it is a ground loop issue in the harness.
 
Joined
Nov 9, 2012
Messages
12,439
Location
Olathe, KS, USA
Assuming you used a wire harness kit...
...sever the Alpine-side neg wire from harness-side neg wire...
then run a separate wire between Alpine-side neg and batt neg terminal. Re-eval for noise.
If no more noise, it is a ground loop issue in the harness.
This Alpine harness has been installed for years by the PO and has worked flawlessly during the time I have had the truck.

This is a recent change and I have not done anything dash or radio related when this started.

The only thing that was in the near time frame to the noticed ticking was around the time I changed the plugs, wires, cap and rotor.

So, I either bumped something or lost a ground cable somewhere.

The fact that my headlights get BRIGHTER when I power the window switch against a closed window tells me I need to look for grounding cables.
 
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sacramento
This Alpine harness has been installed for years by the PO and has worked flawlessly during the time I have had the truck.

This is a recent change and I have not done anything dash or radio related when this started.

The only thing that was in the near time frame to the noticed ticking was around the time I changed the plugs, wires, cap and rotor.

So, I either bumped something or lost a ground cable somewhere.

The fact that my headlights get BRIGHTER when I power the window switch against a closed window tells me I need to look for grounding cables.
Or a new head gasket:slap:
 

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