Resistor spark plugs

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Resistor spark plugs

Postby dggt6 » Sat Sep 07, 2013 5:18 pm

Hi Guys,
How important is it to NOT have normal spark plugs?
Do they throw out so much RF that the MS will not function properly, or is it just a bit that can it be compensated by adjustment inside the MS?
I could ask the same question about spark plug leads?

Thanks,
Doug
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Re: Resistor spark plugs

Postby Elvin » Mon Sep 09, 2013 12:44 am

The main purpose of resistor spark plug is to incorporates a ceramic resistor to suppress ignition noise
generated during sparking.
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Re: Resistor spark plugs

Postby W113 » Mon Sep 09, 2013 12:11 pm

A bit too general to answer, but here is my $0,02 worth.

For some ignition systems it is mandatory to have some kind of external resistance in the spark circuit ( ie plug wires - plugs)
EDIS will not work more than a few seconds with low ohm (ie < 1kOhm) leads and std zero ohm plugs. Resistance per wire/plug needs to be more than 5kOhms.
A fault code will be generated and EDIS will shut down. Power off for several seconds needed to reset EDIS.

Also, there have been a number of reports over quite a few years on this forum with MS boxes resetting for reasons "unknown" , that has been cured by resistor plugs and/or wires

Best regards

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Re: Resistor spark plugs

Postby dggt6 » Tue Sep 17, 2013 4:37 am

Thanks Guys,
I have been having all sorts of trouble getting my mega squirting. I have been through all the usual fixes (reverse the VR sensor etc etc) and am now grasping at straws! I have confirmed that my plugs (BP6ES) are NOT the resistor type and equivalent resistor plugs for the 2500 are not common down here. I am yet to check my leads. I was just wondering if the new plugs could be my silver bullet!?

Thanks,
Doug
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Re: Resistor spark plugs

Postby jsmcortina » Tue Sep 17, 2013 5:00 am

BPR6ES (used on Rover V8) is obtainable or the colder BPR8ES. I used to runs 7s, but wasn't able to find a resistor version of that.

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Re: Resistor spark plugs

Postby DaveEFI » Tue Sep 17, 2013 5:31 am

dggt6 wrote:Thanks Guys,
I have been having all sorts of trouble getting my mega squirting. I have been through all the usual fixes (reverse the VR sensor etc etc) and am now grasping at straws! I have confirmed that my plugs (BP6ES) are NOT the resistor type and equivalent resistor plugs for the 2500 are not common down here. I am yet to check my leads. I was just wondering if the new plugs could be my silver bullet!?

Thanks,
Doug


There are two issues here - tach input to MS (from VR sensor, etc) and spark output from whatever (MS, EDIS) and so on. If you have a problem getting a tach signal to the MS reliably, the plugs won't matter as the two are totally separate . What does a tooth log say? Is it loosing sync when running?
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Re: Resistor spark plugs

Postby jsmcortina » Tue Sep 17, 2013 6:16 am

I've seen cases where non-resistor plugs caused interference and injected noise into the tach-in signal causing sync-loss.

James
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Re: Resistor spark plugs

Postby DaveEFI » Tue Sep 17, 2013 7:21 am

jsmcortina wrote:I've seen cases where non-resistor plugs caused interference and injected noise into the tach-in signal causing sync-loss.

James


I'm sure anything is possible.
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Re: Resistor spark plugs

Postby dggt6 » Tue Sep 17, 2013 7:53 am

Thanks guys for your input.
The long story is that my Triumph GT6 is still running with the stock carby, dizzy and plugs setup. I was hoping isolate any MS problems from "engine problems" by getting the MS to "read only" before giving any orders.
I modded the V3 board for EDIS but did NOT connect the EDIS coil unit, just the VR, O2, temp sensors and vacuum.
All the sensors worked but the RPM was scattered, the logs were all over the place and the MS would "shut down" over 1200RPM.
I returned the V3 board mods to "normal" with no change in the erratic RPM and the "shutting down".
I have also changed the VR sensor with no change noticed.
This is why I have started looking "outside" the MS such as the plugs and leads.
5 out of 6 local Auto stores do not stock the resistor plugs. Hopefully the last is lucky!
I will try and get a shot of the tooth log tomorrow.

Thanks again for your help,
Doug
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Re: Resistor spark plugs

Postby DaveEFI » Tue Sep 17, 2013 8:39 am

Do you have EDIS with the EDIS unit - or MS providing wasted spark? If EDIS, I'm not sure the EDIS unit would work happily with no coils - I suspect not. But I've not tried it.

If you are using the VR sensor direct to MS to provide the tach signal, it needs to be set for this - not EDIS. The EDIS unit converts the 36-1 signal into a simple tach signal. If MS is required to do this it has to be set correctly.
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Re: Resistor spark plugs

Postby dggt6 » Tue Sep 17, 2013 5:26 pm

Ah Ha!
The VR wires bypass the EDIS unit and the power is off to the EDIS unit, BUT I think I may still have the MS set to EDIS. I have changed so often I have forgotten where I am up to!
Which ignition type should I select to just "check" the VR signal?

Thanks,
Doug
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Re: Resistor spark plugs

Postby DaveEFI » Wed Sep 18, 2013 1:11 am

If you wish to use a VR sensor and EDIS toothed wheel to provide the tach signal you'll need to check the manual on how to do this. However, if you intend using EDIS, not sure why you'd bother - a Stim will replicate an EDIS tach signal for test purposes. EDIS is usually very reliable and easy to install.
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Re: Resistor spark plugs

Postby jsdevel » Fri Oct 13, 2017 1:02 am

I was having all sorts of noise issues with my install running with BP6ES. I could've sworn I ordered BPR6ES, but no. I literally did everything else you could think of to cure the resets. Sometimes I thought I had it squelched, but then it would come back randomly. Issues like this for the noob are not for the faint of heart. Finally after pouring over the forum and re-reading the manual I thought to double check the spark plugs that we're installed and sure enough they weren't the resistor kind. Drove to the Zone immediately for a pack of BPR6ES plugs but they were out. I cross referenced them to a set of AC Delco R43XLS plugs which they had in stock. Installed them right there in the parking lot. Noise entirely gone!

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Re: Resistor spark plugs

Postby DaveEFI » Fri Oct 13, 2017 2:24 am

dggt6 wrote:Hi Guys,
How important is it to NOT have normal spark plugs?
Do they throw out so much RF that the MS will not function properly, or is it just a bit that can it be compensated by adjustment inside the MS?
I could ask the same question about spark plug leads?

Thanks,
Doug


It is not so much MS as the type of ignition system in use. If you fit a different one from OEM which didn't use resistor plugs, it is generally easier to provide the degree of suppression needed by using the resistor version.
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