Checking Coil Packs
Thread Starter
Joined: Jan 2002
Posts: 7,538
Likes: 4
From: Tomball, TX.
Checking Coil Packs Does anyone know a way to check each coil pack?
We had a problem with my car breaking up when I would stage the car on the convert. I changed the coil packs from my Dads car and it cleared up the problem. I really dont want to replace all of them if I dont have to.
Coach
We had a problem with my car breaking up when I would stage the car on the convert. I changed the coil packs from my Dads car and it cleared up the problem. I really dont want to replace all of them if I dont have to.
Coach
i know you can take a ohms test on each one, and see if there is any major difference in readings.
take a know good coil and see what reading you get for your baseline. but! this is not a perfect test! i do this with injectors and have had the readings good and still have a bad injector!
if you have a digital oscillascope? this would be the best way to test them. hook it up and you can watch your coil output under running and load conditions. then if there is a break up of the coil, it will show on the screen.
take a know good coil and see what reading you get for your baseline. but! this is not a perfect test! i do this with injectors and have had the readings good and still have a bad injector!
if you have a digital oscillascope? this would be the best way to test them. hook it up and you can watch your coil output under running and load conditions. then if there is a break up of the coil, it will show on the screen.
Problem is that if they're failing it's going to be a high voltage related problem, which is something that is inherent with high voltage (I've worked with it for years)
High voltage will arc where you wouldnt' expect it, if the seals in the coil packs ever went bad, that's all it takes for a little moisture/contamination to get in there and then it will start arcing. Higher loads (rpm in this case) will make it worse as well.
I hate to say it but they're gonna be a pita to see which is arcing. Only real way would be to have a scanner hooked up and see which cyl. is misfiring... and start with that. But, I assume you have your knock sensors out and don't have that option.
Maybe time to upgrade to some 6 litre truck coils, and leave your 8 as spares for maybe one of the other cars in the stable that may still have the knock sensors in it.
Actually, swapping them one at a time with one of those cars and watching on that car for a misfire might be the best way to find the bad one... or 2 or however many may be going.
High voltage will arc where you wouldnt' expect it, if the seals in the coil packs ever went bad, that's all it takes for a little moisture/contamination to get in there and then it will start arcing. Higher loads (rpm in this case) will make it worse as well.
I hate to say it but they're gonna be a pita to see which is arcing. Only real way would be to have a scanner hooked up and see which cyl. is misfiring... and start with that. But, I assume you have your knock sensors out and don't have that option.
Maybe time to upgrade to some 6 litre truck coils, and leave your 8 as spares for maybe one of the other cars in the stable that may still have the knock sensors in it.
Actually, swapping them one at a time with one of those cars and watching on that car for a misfire might be the best way to find the bad one... or 2 or however many may be going.
Before you replace the coils, if you have stock 99+ valve covers/coil brackets, look very carefully at the wires underneath where they pass by the bosses on the valve covers under the coil brackets, lot of times the wiring wears through and shorts out causing all kinds of headaches.
Before you replace the coils, if you have stock 99+ valve covers/coil brackets, look very carefully at the wires underneath where they pass by the bosses on the valve covers under the coil brackets, lot of times the wiring wears through and shorts out causing all kinds of headaches.
good hunting
you could probably use a tech 2 (gm scan tool) but if the knock sensors were removed, i dont believe you'll be able to see which cylinder is misfiring.. how every i'm not sure there also could be a function to view each coils outputs?
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Former Vendor
Joined: Mar 2009
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http://www.bmotorsports.com/shop/pro...oducts_id/1591
You also want to check the connections by wiggling them while running to see if you have an intermittent connection in the harness somewhere. Sometimes it can be a bad factory crimp or the terminals can be damaged or the spring elements worn out. We carry the connectors for both the coils themselves and for the coil subharness.
A scope measuring across a current sense resistor would tell you about each coils performance but this sort of check is typically overkill when you can simply replace the parts for less in time/money.
Teching In
Joined: Mar 2009
Posts: 7
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From: Martinsville, Indiana
anyone try a timing light? I had one go bad last year in my truck and tried the light on each plug wire until I found the one that was firing erratically. Very quick and easy, hardest part was trying to get the right coil at oreilly's.
