Coach 02 A3 Z/28

iTrader: (10)

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

yrlosing

iTrader: (6)

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.

JL ws-6

iTrader: (50)

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.

kp

iTrader: (34)

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.

tomz28

iTrader: (20)

i had this happen to me i think this is your best bet. i have not seen a bad coil so far. ive had a few friends with this same thing going on. it was the harness
good hunting

Carbed4thGen

iTrader: (2)

I Know on stock Ford's we have a system that can show you a waive form to see if the COP is taking a **** is there anything from GM that the dealerships have?

WhiteLTone

iTrader: (18)

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?

tektrans

iTrader: (23)

change them all Coach, if one went the others probably aren't far behind.

Bmotorsports

Can always go with a set of the higher output latest generation truck coils:
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.

the schoob

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.

dlove

iTrader: (23)

Not sure if I missed something, but I have never know the knock sensors to pick up a misfire. That is the job of the crank sensor.