Coil pack test - Is there an easy way?

[Charlie207]

I know LS coils are pretty durable, but I'm having a hard time finding a procedure for testing them, with in the car, or on the bench.

Does anyone have a tip or two?

 

[strutaeng]

Umm, I have never wondered that actually.

Maybe there's a resistance test out there I'm not aware of? Like on Haynes Manual?

 

[OR VietVet]

Easy way? Swap wires and see if the misfire follows. Are you trying to address a code? What is the code or problem?

 

[Charlie207]

Easy way? Swap wires and see if the misfire follows. Are you trying to address a code? What is the code or problem?

No codes. I'm trying learn how to test them. I have a multimeter and oscilloscope, and like to know how things work.

I have eight spare coils from my engine swap, and figured it'd be nice to know if they were all good.

 

[strutaeng]

I checked and Haynes Manual does not show any testing procedures for the V8 coil packs, only for the V6 engines, which are obviously different.

There's a guy on the GMT400 forum that swore LS coil packs fail left and right, Monday tru Sunday (same guy also says the SBC is superior because it has ONE coil pack vs 8, LMAO!) Anyways, I've been driving these engines (high 200k+ mileage too) now for a few years and thousands of miles and I can now say he's full of $hit. I'm sure they do in fact fail (what doesn't?) but the failure rate seems very low, especially the OEM ones.

You can probably get a good one, and compare the resistance to your 8 on the bench.

Or, I'd say just swap one by one on a known good vehicle and drive it a few days, if you don't get a misfire, put a piece of tape and label it: GOOD.

 

[Charlie207]

I checked and Haynes Manual does not show any testing procedures for the V8 coil packs, only for the V6 engines, which are obviously different.

There's a guy on the GMT400 forum that swore LS coil packs fail left and right, Monday tru Sunday (same guy also says the SBC is superior because it has ONE coil pack vs 8, LMAO!) Anyways, I've been driving these engines (high 200k+ mileage too) now for a few years and thousands of miles and I can now say he's full of $hit. I'm sure they do in fact fail (what doesn't?) but the failure rate seems very low, especially the OEM ones.

You can probably get a good one, and compare the resistance to your 8 on the bench.

Or, I'd say just swap one by one on a known good vehicle and drive it a few days, if you don't get a misfire, put a piece of tape and label it: GOOD.

Yeah, I was under the impression they either worked or died, no in-between.

 

[OR VietVet]

I have not looked but what does you tube say?

 

[j91z28d1]

some info.

using LS coils as wasted spark

curious about swapping my DP car over to LS but still running the EEC and will continue to so with a simple plug and play reversible harness i can make will my car be able to run LS coils due to the c

turboford.org

while you might be able to fire the coil in open air, you can't really test if they will fire a plug properly under load that's why it's standard practice when getting missfie code to swap the coil with another cyl. to see if the miss follows the coil.


not saying old guy us right, but they do kinda fail more often than what old guys are used to. it could purely be the odds of it happening is higher with 8 than one. or we seem to have gone backwards in quality parts wise. old coils might just have been better. I had a 96 with 325k when I sold it.. still on the oem coil. I got my 2011 with 130isj on it and it's already had one changed out.

now that said, the ls coils are very much more complicated. lots of electronics to fail in them. old coils are mostly just a transformer. ls coils do put out more spark power too.

 

[Doubeleive]

the only way I know of is either you get some misfire from it or you don't
if the ones installed now are for sure working fine, pull them out and swap in your other set, drive it and see what happens if you have no problems after 3-4 days either leave them in or swap the others back in, failure rate is pretty low for oem

(the old fashion way)**if you can hear/sense the misfire but it doesn't throw a code, start pulling wires one by one until you can't hear the difference any more
(new way) may be to connect a scanner like the tech2 and log the misfire counts, then swap coils and see if the misfire follows the coil.

pretty sure they are basically a step-up transformer generating a high voltage pulse that shoots thru the spark plug ceramic to the electrode igniting the fuel , so you would likely need a high voltage tester and know what the specs should be to really call it "good"

a ohm resistance test can be done but the coil could still be no good because there is no load, which could be where it fails
there are little cheap tools sort of like a household power socket tester that shows if the coil is firing or not but still doesn't tell you if it is 100% or not.

 

[swathdiver]

Watch this and look at the tool he uses to see if the coils are sparking through the wires. We use our Tech-2s too.

 

[EddieC]

I used to fix things that weren't broken and often made them worse.
I learned to get past that habit.
I guess if I had spares I wouldn't worry about their condition until I needed them which seems to turn out to be never for me.

As a followup, my original coils are 16 years old and have not been a concern.

 

[strutaeng]

some info.

using LS coils as wasted spark

curious about swapping my DP car over to LS but still running the EEC and will continue to so with a simple plug and play reversible harness i can make will my car be able to run LS coils due to the c

turboford.org

while you might be able to fire the coil in open air, you can't really test if they will fire a plug properly under load that's why it's standard practice when getting missfie code to swap the coil with another cyl. to see if the miss follows the coil.


not saying old guy us right, but they do kinda fail more often than what old guys are used to. it could purely be the odds of it happening is higher with 8 than one. or we seem to have gone backwards in quality parts wise. old coils might just have been better. I had a 96 with 325k when I sold it.. still on the oem coil. I got my 2011 with 130isj on it and it's already had one changed out.

now that said, the ls coils are very much more complicated. lots of electronics to fail in them. old coils are mostly just a transformer. ls coils do put out more spark power too.

Interesting, I thought these coils are the same: just a copper-wound (or aluminum?) transformer, no different than the older ones?I've never opened one up...but probably just windings.

What electronics are you talking about?

The SBC Vortec are notorious for having the ignition control module fail. The standard procedure is for guys to replace the ICM along with the coil. Coils are probably okay, but you know the parts changer mentality: "oh, I'm going to replace it since it's got *** miles." The ICM has that thermal paste, and a lot of guys blame that for failures; I don't know if that's true TBH. Most will recommend having an extra ICM in your glovebox in case you are need it, along with a cap and rotor because it's failed on them at least once. I'm glad that system was phased out because in my experience, a failure will leave you stranded: engine completely dead. And aftermarket replacement parts are notoriously poor quality, which doesn't help either.

A failure in an LS coil and you can at least get off the road with a misfire. The ECU doing the switching internally I guess replaced the ICM (?) Very rare for ECUs to fail. If anything, I think the LS are way more reliable on this aspect, but it's okay if you disagree.

The 8 coils having more power than 1 is more like a performance thing.

 

[opfor2]

I just watched his video, and he stated NOT to use anti-seize on the plugs oooops I guess I blew it on that one

 

[j91z28d1]

Interesting, I thought these coils are the same: just a copper-wound (or aluminum?) transformer, no different than the older ones?I've never opened one up...but probably just windings.

What electronics are you talking about?

The SBC Vortec are notorious for having the ignition control module fail. The standard procedure is for guys to replace the ICM along with the coil. Coils are probably okay, but you know the parts changer mentality: "oh, I'm going to replace it since it's got *** miles." The ICM has that thermal paste, and a lot of guys blame that for failures; I don't know if that's true TBH. Most will recommend having an extra ICM in your glovebox in case you are need it, along with a cap and rotor because it's failed on them at least once. I'm glad that system was phased out because in my experience, a failure will leave you stranded: engine completely dead. And aftermarket replacement parts are notoriously poor quality, which doesn't help either.

A failure in an LS coil and you can at least get off the road with a misfire. The ECU doing the switching internally I guess replaced the ICM (?) Very rare for ECUs to fail. If anything, I think the LS are way more reliable on this aspect, but it's okay if you disagree.

The 8 coils having more power than 1 is more like a performance thing.

each ls coil a 100% has electronic circuits in them. they are not just coils like back in the day. they get more complicated the newer you get too, Google ls smart coils for info on that stuff. the best place to learn what it takes to fire ls coils is going to be the megasquirt message boards, they will have diagrams and stuff for you.


again, which is better? we aren't going to even go back to one coil and dizzy. but I will say this, when a obs loses spark you can fix it in a parking lot for cheap by replacing 2 or 3 parts from any parts store. an ls ign starts messing up there's pages and pages of trying to fix random misfires and nonsense. it might be better but it's definitely not more simple. but same could he said for a carb.

 

[strutaeng]

each ls coil a 100% has electronic circuits in them. they are not just coils like back in the day. they get more complicated the newer you get too, Google ls smart coils for info on that stuff. the best place to learn what it takes to fire ls coils is going to be the megasquirt message boards, they will have diagrams and stuff for you.


again, which is better? we aren't going to even go back to one coil and dizzy. but I will say this, when a obs loses spark you can fix it in a parking lot for cheap by replacing 2 or 3 parts from any parts store. an ls ign starts messing up there's pages and pages of trying to fix random misfires and nonsense. it might be better but it's definitely not more simple. but same could he said for a carb.

Carburators? That's WAY before my time, so I can't argue about anything carbs. Heck, my Dad hasn't even owned a carbureted vehicle since the 80s.

Where do you see that there's more electronics here? It's looks about the same to me. I'm obviously comparing the two generations of the same timeline (one generation back vs one generation forward and of course things change more) Guys throwing parts at trucks is simply because lack of diagnostics knowledge. Both parties are guilty. I am as well in my younger years (my SBC years). I have no shame in admitting that. My dad was never a gearhead and I've learned this myself, out of necessity.

But agree with you reliability (throw power and emissions in there) vs simplicity. You can't have your cake and eat it too....so I digress.

 

[j91z28d1]

I still work on carburetor at work. you can order rebuild kits thru napa of all places haha.

I don't know why you keep fighting about ls coils lol. here's a schematic, just takes 2 secs to Google how they work.you can also cut an old one open, almost every stand alone coil these is more than a simple transformer like old coils do. (high end import stuff is wild) you can't even fire a ls coil with a old Gen 1 ecm without a control box inline. for years guys wanted to use coils on sbc tpi cars and you just can't, even trying wasted spark. there's no way to get a obd1 ecm to output the squad wave needed to tell the coils to fire. the smart coils can even measure the amount of power used to fire the spark plug based on all kinds of stuff. that way they become a "sensor" to help you diagnose cyl pressure.