Chasing ignition noise! Anybody up for helping me diagnose?

[BuzzardsBayDave]

I think you may have this backwards. My factory plugs are “R” plugs.

No, worked in automotive industry for 15 yrs, not backwards. Around the early 80's or before due to engine management and better circuitry R type plugs were not in the vehicles from the factory.

For the Op's application, I went to Autozone web page and R plugs are not the factory replacement.

 

[BuzzardsBayDave]

It is direct from the battery. I have a fuse BLOCK (aftermarket for hooking up multiple radios/accessories) that is run straight off the battery. Not the vehicle fuse box.

1) Try for a moment - attaching the + wire directly to the battery.( to eliminate that set up )
2) Check all grounds in engine bay. ( start cheap ) Loosen the strap bolts, clean the area of any rust with tooth brush sized wire brush and retighten.

 

[a417]

Loosen the strap bolts, clean the area of any rust with tooth brush sized wire brush and retighten.

I've gotten in the habit of giving them a dose of Permatex 80370 (or the napa equiv, can't remember the number) battery terminal sealer after to help slow down corrosion and rust.

 

[RFI-EMI-GUY]

No, worked in automotive industry for 15 yrs, not backwards. Around the early 80's or before due to engine management and better circuitry R type plugs were not in the vehicles from the factory.

For the Op's application, I went to Autozone web page and R plugs are not the factory replacement.

A lot of generalization here.

First the OP should probably use whatever the OEM recommends and that may include R plugs as an option. AUTOZONE is not the authority on OEM parts.

Resistor plugs still exist in the modern world. However I have seen that in some Japanese vehicles a resistor cartridge is inserted into the COP before the boot and spring are attached. Those vehicles probably don't use resistor plugs because it would be redundant. Resistor spark plug wires were also common until the COP.

EDIT: "Ford has a ferrite slug within the spring for the COP. That may preclude use of R plugs in Ford Triton engines."

But actually it does not:

I just now checked two spare SP-493 spark plugs from my parts bin. They have around 5 or 6K resistance. These are same plugs the dealer replaced my 2001 vintage OEM plugs years ago. How do I know, I kept the old OEM plugs and the boxes for the replacments. The OEM plugs also measure around 5 or 6K resistance. Although an outlier was 10K which is interesting potential failure mode.

So a blanket statement that says the auto industry stopped using resistor plugs back in the 80's is false.

NGK.com: What is a Resistor Spark Plug?

www.ngk.com

 

[RFI-EMI-GUY]

FORD PLUG: PRODUCT SPECIFICATIONS

Part #	SP-493
SKU #	534651
Weight	0.1lbs
Ground Electrode Material	Nickel
Heat Range	3
Center Electrode Tip Material	Platinum
Center Electrode Core Material	Copper
Resistor	Yes

This is supposedly an OEM 5.7L HEMI plug. Dont know if it belongs to the OP's model:

NGK SPLZFR5C11
SP = platinum;
L = thread reach 26.5mm;
Z = extended projected tip;
F = 14mm thread, 19mm reach, 5/8" hex, gasket/washered seat;
R = resistor;
5 = HR 5;
C = firing end construction;
11 = 1.1mm gap
- Application: 5.7 Eagle OEM – This is what Chrysler puts in

 

[prcguy]

Don't turn your nose up at Sparkomatic DC noise filters. I've been using them since the early 80s and they work very well being a choke input with large filter capacitor. I've probably gone through a 10 pack of the NF 500s shown in picture below using them on friends vehicles. Next to it is my ultimate DC line filter I built from scratch using a 40 amp rated 41.7uh choke and an 8.3 Farad 16 volt capacitor as a choke input filter with overvoltage and spike protection. Nothing gets through that filter and it has four 45A Anderson Power Pole connectors on the output side and a 40A aircraft circuit breaker.

For the OPs problem I'm an advocate of pinpointing the problem before throwing any fixes at it. From the description there is a good chance the noise is radiated off ignition components like spark plugs, wires, distributor, coil packs, etc. I have had good success using a small AM or AM/SW receiver and probe around inside the engine compartment listening on the AM broadcast band and at 27MHz if its a SW receiver. I've used both an AOR AR8200MKIII and a Yupiteru MVT-7100 receiver for this. You can turn on the CB and listen to the noise then probe around with the portable radio so you know you are tracking the exact same noise. Then use the attenuator built into the receiver to numb it up so you can probe closer, or wrap it in aluminum foil with a small opening near the internal AM antenna to further numb it up so you can really pinpoint the source.

The worst vehicle I had here to sniff was an mid 80s Toyota four runner with a lot of mods. This truck had nasty spark plug noise from HF through 2m amateur. The spark plug wires and the distributor were the main offenders and I gave the owner a bunch of copper tape to wrap the distributor then some braided tubing for the spark plug wires and instructions that he may need a tune up if the shielding over the spark plug wires retarded the timing. Fortunately all the shielding went in with no timing change and the result was a very useable radio inside the truck where before his truck outside my house would wreak my reception in the house on my radios.

 

[RFI-EMI-GUY]

PRC GUY
Thats a serious filter. Motorola had a black box filter with big inductor they sold for the RED lead of Micor's. If I recall it had a transient snubber in the way of a back-EMF diode across the inductor.

 

[prcguy]

The Motorola choke and some of the snubber parts are in my filter. My secret is out, I am nothing now.

But there ain't no 8.3 Farads in the original Motorola filter, maybe only a few thousand uf.

PRC GUY
Thats a serious filter. Motorola had a black box filter with big inductor they sold for the RED lead of Micor's. If I recall it had a transient snubber in the way of a back-EMF diode across the inductor.

 

[RFI-EMI-GUY]

The Motorola choke and some of the snubber parts are in my filter. My secret is out, I am nothing now.

But there ain't no 8.3 Farads in the original Motorola filter, maybe only a few thousand uf.

You can never have enough Farads I always say. I dont think Farads were commercially available back in the Micor days.

 

[a417]

just now checked two spare SP-493 spark plugs from my parts bin. They have around 5 or 6K resistance. These are same plugs the dealer replaced my 2001 vintage OEM plugs years ago. How do I know, I kept the old OEM plugs and the boxes for the replacments. The OEM plugs also measure around 5 or 6K resistance. Although an outlier was 10K which is interesting potential failure mode.

Did you use a standard DMM ohmmeter or a megger?

I recently found out that (Champion) "R" type plugs cannot be reliably checked with a garden variety DMM as the resistance cannot be reliably measured at low voltages, while the "FISS" type resistor plugs can be ohm'd out with normal values between 3k - 10k ohms...as I was working my way thru a hard-start issue on a engine. The champion technical support gentleman was quite pleasant to talk to on the phone.

 

[RFI-EMI-GUY]

Did you use a standard DMM ohmmeter or a megger?

I recently found out that (Champion) "R" type plugs cannot be reliably checked with a garden variety DMM as the resistance cannot be reliably measured at low voltages, while the "FISS" type resistor plugs can be ohm'd out with normal values between 3k - 10k ohms...as I was working my way thru a hard-start issue on a engine. The champion technical support gentleman was quite pleasant to talk to on the phone.

I have an old school Realistic analog VOM that is a clone of the famous Simpson 260. It has a 9V battery for the high ranges. I don't use my DMM exclusively, because it is prone to being fooled.

 

[a417]

I have an old school Realistic analog VOM that is a clone of the famous Simpson 260. It has a 9V battery for the high ranges. I don't use my DMM exclusively, because it is prone to being fooled.

Understood, I have something similar - but I wasn't using it for this. I was trying to figure out why a cylinder was down, and ohm'd out some R type plugs to get values of 500, 1400 and 9600 (500 and 9.6k right out of the box) only to find out that I needed access to high voltage test equipment and was basically wasting my time.

 

[ClemsonSCJ]

No, worked in automotive industry for 15 yrs, not backwards. Around the early 80's or before due to engine management and better circuitry R type plugs were not in the vehicles from the factory.

For the Op's application, I went to Autozone web page and R plugs are not the factory replacement.

Not trying to be hard headed here but if you go to autozone’s website and search for my vehicle specific spark plugs (09 Jeep Grand Cherokee 5.7 Hemi) I went through every single plug that is specific for my vehicle and they are all resistor plugs. Couldn’t find a single non-resistor plug as an option to fit my vehicle.

Also, after extensively searching the interwebs, I can only find information on the detrimental effects of throwing non-resistor plugs in a vehicle that calls for resistor plugs (which I can’t find a single source to say mine doesn’t despite your continuous assertion that it does) and not a single bit of information about any ill effects of putting resistor plugs in a vehicle that calls for non-resistor plugs. But again, all the information I’ve been able to find tells me 3 things:
1) resistor plugs are meant to cut down rfi and are therefore recommended for any vehicle that uses a computer to monitor performance, which is pretty much all vehicles now...therefore from deductive reasoning pretty much all vehicles with an on-board computer SHOULD use resistor plugs,
2) the entire purpose of this post was about eliminating RFI in my radio so I would imagine resistor plugs would be the best choice for my application
3) putting resistor plugs in, even if that’s not what it came with from the factory, isn’t going to hurt anything. Whereas if I do put non-resistor plugs and that’s not what’s supposed to go in there, that can cause all sorts of ignition issues.

 

[RFI-EMI-GUY]

Understood, I have something similar - but I wasn't using it for this. I was trying to figure out why a cylinder was down, and ohm'd out some R type plugs to get values of 500, 1400 and 9600 (500 and 9.6k right out of the box) only to find out that I needed access to high voltage test equipment and was basically wasting my time.

I have no idea why you had that difficulty. You may find corrosion layer on the spark plug tip and the outer contact that needs to be scratched through, but a megger should not be required to measure the internal resistance of a spark plug. I just did so about 6 times with my simple VOM in my garage. 5 of mine were between 5 and 6 K the other was 10K and may have been a different plug as a two of my OEM's were changed during warranty. The Champion Rep may be recommending a megger because that is how they do so in the factory. And yes, maybe using a megger, a bad plug will measure low because of HV breakdown across the resistor slug due to moisture. But assuming a good plug, using a VOM you should be able to se a nominal resistance vs a dead short or open.

If you have a bad plug where coolant has leaked into it from above or below, the resistor might be damp and in that case a low value might result.

 

[prcguy]

Resistor plugs have been around for 50+ years and were used by car mfrs to reduce or eliminate AM car radio interference. Some need them, some don't. I have not heard they are used due to computer's in cars, its for radios.

Not trying to be hard headed here but if you go to autozone’s website and search for my vehicle specific spark plugs (09 Jeep Grand Cherokee 5.7 Hemi) I went through every single plug that is specific for my vehicle and they are all resistor plugs. Couldn’t find a single non-resistor plug as an option to fit my vehicle.

Also, after extensively searching the interwebs, I can only find information on the detrimental effects of throwing non-resistor plugs in a vehicle that calls for resistor plugs (which I can’t find a single source to say mine doesn’t despite your continuous assertion that it does) and not a single bit of information about any ill effects of putting resistor plugs in a vehicle that calls for non-resistor plugs. But again, all the information I’ve been able to find tells me 3 things:
1) resistor plugs are meant to cut down rfi and are therefore recommended for any vehicle that uses a computer to monitor performance, which is pretty much all vehicles now...therefore from deductive reasoning pretty much all vehicles with an on-board computer SHOULD use resistor plugs,
2) the entire purpose of this post was about eliminating RFI in my radio so I would imagine resistor plugs would be the best choice for my application
3) putting resistor plugs in, even if that’s not what it came with from the factory, isn’t going to hurt anything. Whereas if I do put non-resistor plugs and that’s not what’s supposed to go in there, that can cause all sorts of ignition issues.

 

[RFI-EMI-GUY]

I noticed while looking for "HEMI" sparkplugs that some insulators are ribbed and others are not. The ribbed insulators should have higher breakdown voltage from the lead contact to the body. How this works in real world with a rubber boot and surrounding valve cover metal is a guess but I thought it interesting that smooth insulators are being offered. If I had a choice it would be ribbed, but maybe there is a mechanical reasoon due to the boot.

 

[RFI-EMI-GUY]

Resistor plugs have been around for 50+ years and were used by car mfrs to reduce or eliminate AM car radio interference. Some need them, some don't. I have not heard they are used due to computer's in cars, its for radios.

I found a bit of discussion on some "tuner" pages about ignition noise confusing the engine control confusers, so it apparently is a concern under the hood of high performance vehicles.

There was a thread recently about Ford getting the bid for a fleet of state patrol cars on the east coast because of ignition noise problems of the HEMI's and the state radio system. If I find the thread I will post it. Not much said. But there are other threads where hams have had a lot of problems with the HEMI.

 

[a417]

The Champion Rep may be recommending a megger because that is how they do so in the factory. And yes, maybe using a megger, a bad plug will measure low because of HV breakdown across the resistor slug due to moisture. But assuming a good plug, using a VOM you should be able to se a nominal resistance vs a dead short or open.

I was way beyond open vs dead shorts in my diagnosis, I was down the sparkplug rabbit hole and ended up on the phone with a factory guy who told me the almost exact same thing as this website. I knew I had plugs that weren't dead or shorted, but I didn't know if they were within spec.

It was really interesting to hear, and he said "hey, you can put a VOM/DMM on one of the plugs, but trying to diagnose an ignition on an "R" type plug w/o a megger is a guessing game". It was a good phone call. Nice to hear an actual educated human imparting knowledge and not just reading a script.

 

[RFI-EMI-GUY]

I was way beyond open vs dead shorts in my diagnosis, I was down the sparkplug rabbit hole and ended up on the phone with a factory guy who told me the almost exact same thing as this website. I knew I had plugs that weren't dead or shorted, but I didn't know if they were within spec.

It was really interesting to hear, and he said "hey, you can put a VOM/DMM on one of the plugs, but trying to diagnose an ignition on an "R" type plug w/o a megger is a guessing game". It was a good phone call. Nice to hear an actual educated human imparting knowledge and not just reading a script.

From the article:

What Are the Different Champion Resistor Types?



"R" Type: Most resistor spark plugs feature a standard "R" type resistor. Most Champion "R" type resistor plugs are Champion SAC-9 suppressors. These extremely reliable resistors are formed from strontium carbonate, aluminum oxide and copper oxide powders. The resistance of a plug with SAC-9 suppressors are capable of combating typical RFI, but cannot be accurately measured with typical low voltage ohmmeters.


"FISS" Type: Fired in Suppressor Seal plugs feature a durable suppressor in the form of a proprietary glass mixture located inside the insulator. FISS plugs can be identified by their black terminal end. Technicians can check the resistance level with a conventional Ohmmeter, which should show a range of 3000-10000 ohms at room temperature.


"Q" Type: Uses a wire wound inductive coil (or electromagnetic suppression) to reduce RFI without negatively affecting ignition performance. "Q" type suppressor plugs are specified for most Evinrude and Johnson outboard engines with CDI.


"X" Type: Have a special resistor to meet more stringent RFI requirements.

To avoid a reduction in performance, resistor types should not be used interchangeably. Use of a non-OE resistor type could result in engine damage and end plug life.

I think what I have in my Ford are FISS types because they have a dark anodized terminal.

I changed my magneto on my lawn tractor a month ago. The new replacement from B&S has an RFI cap on the end that slips over the metal base of the plug and grounds it. The OEM plug is resistive. I measured the one I removed today. Apparently B&S is complying with some requirement by providing RFI suppression on new lawn mowers.

Champion Patent:

US3959184A - Modified copper-aluminum suppressor element - Google Patents

An improved ceramic article useful after firing as an electrical suppressor element, especially suitable for use in spark plugs, is disclosed. The suppressor element is a copper-aluminum composition modified with a mangesium, calcium, strontium or barium metal compound. The numerical value of...

patents.google.com

 

[krokus]

@ClemsonSCJ have you replaced the plugs? I have a 2010 WJ, and the plugs are only rated for 30,000 miles. Also, they have COP on one side of the engine, with a high voltage lead to the matching plug on the other side. (Unless the Hemi engine is that different in base design.)