OH NO!!, GM 3.3L (3300) V6 miss/dead coils..

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Feb 19, 2009
The Woods of NY
Howdy! From snowy upstate NY... I ran in to a problem recently... the last few days, about 600 miles i've been dealing with dead/weak/erratic spark from a couple of the towers.. It has the 3 coil, 2 towers on each coil, and a Ignition control module. The coil with tower 1 and 4 on it,(top) cyl 1 has a good spark every 1/2 sec or so, cyl 4 is bright blue rapid spark, .. Next the coil with towers 5 and 2,(middle) cyl 5 has no spark, while cyl 2 sparks as expected.. same story with the last coil,(by connector) tower 3 is iffy, while tower 6 is full working spark.. What i did to try to fix this.. I had this i thought same issue 3 weeks ago, replaced the OEM GM ICM, and all 3 coils with BWD from advanced auto, problem fixed.. it came up again, i thought the ICM went out AGAIN, so i changed out the ICM but this time the the miss stayed.. I changed out the coil packs again, same story, changed the spark plus, and even the CSPS, checked grounds, battery has 13.X with engine off, 14.5V engine idling... and its still missing.... now this miss stated off real weak, as it would only miss say passing at 65MPH, then it just stated getting worse.. it at this time is on 3 cyls.. What tooooo doo? HelP!! Thank you much...
I suspect a problem with either your harmonic balancer like the rubber is degrading or the crank sensor beneath. If your crank sensor gap is off just a touch a different ignition module might help but the real cause is underlying and still there. These cars, the ignition module has the authority to spark without the PCM; however, it tells the PCM when to fire the injectors, and the PCM talks over the "bypass wire" to allow spark advance. Yet it should still be sparking, with retarted timing, as a failsafe.
Since you say that each coil has different spark from its terminals I have to ask how are you determining this and what are your symptoms? Each coil fires its 2 companion cylinders simultaneously. So if 5 has no spark and 2 does maybe there is a problem in one of the cylinder's plug wire or plug? Have you checked/changed plugs and wires? Are you checking for spark at the plug wire while crank or engine running? You are suppose to ground the coil's companion cylinder while checking spark from the other terminal. Do you have a misfire with engine running? Your problem could be a fuel injector problem.
Hi to update you... its getting worse, in a hurry... well its so bad now that On snow, you can NOT spin the tires at WOT.. the harmonic balancer looked good, its tight, no vibrations, or bent rings.. i even cleaned it, to like new thinking it was dirt or something on the rings messing with it... I've also replaced the crankshaft position sensor, with no change.. 2X Ignition Control module 2X coils.. Sparkplugs.. Fuel filter Wires do have 31K miles on them, but are only a few months old.. Checked ALL connectors, everything is tight and clean.. I have NO codes, Well just code 12, 3X. So the ECM passes.. I have miss fire all the time, idle, WOT, just driving down the road at 55MPH, the dash will shake so much i cant even read the time on the radio... Is it possible that "New HONG KONG" ICM is bad out of the box? It was sealed, BUT, it looked like they did it in the store.. Whats even more crazy is the first Hong Kong replacement only lasted 3K miles. It feels like the problem i had 3K miles ago.. also had no spark 1 tower on each coil, after replacing the coils, and still having no spark, i replaced the ICM, and all was fixed for a couple of weeks... Im looking over EVERYTHING, but it all checks out.. and all point to the ICM. maybe i should get a GM one from the yard? If thats not the issue, then i might have to take my 20+ year old to the shop! Gasp! Im off to check the fuel injector pulse, and to make sure the ICM is getting 12V. Much Appreciated, cheers.
I still say if you are getting good spark on at least one coil tower of each coil then the ICM is not indicated and is firing the coil and the coil is completing the circuit. There could be a problem in some of the plugs or wires, although you are saying they are new and wires are not old. The misfire might not even be due to the ignition and could be the injectors or fuel system related.
Update: I have 6 injectors all receiving signal. Tested Volts. Pin H for the Ign Control Module has 12.45V strong. BUT. testing the connectors for the coils, on each pair, the BOTTOM terminal has the same 12.45V, but the top one is DEAD. Tested with a volt meter, positive to the terminal, neg to the body.. Has to be the IGN CONTROL MODULE again?
If you are talking about the 2 terminals on the ICM that connect to each coil then that sounds normal. The first one is negative and the second one is positive. Stick you voltmeter lead across the terminal and i bet you get battery voltage. Also connect a test light to ground and to the positive coil terminal and engine cranking see if test light flashes (although sometimes a test light won't pick it up and an LED is needed). If so the ICM is working. If you are getting good spark out of one coil tower and not the other then the ICM is not indicated but probably the coil or spark plug wire. Also your injectors could be getting pulse signal but the injector internal resistance could be off or they could be clogged up.
This issue started off as a slight miss when at WOT, then it just got worse.. In 2 days, about 250 miles, I had no spark for the 3 cylinders in the front... Like i said, i cant think i really got 3 bad computers.. But i had this same issue 3 weeks ago,, replaced ICM and i was set.. I replaced the ECU, (The main computer in the dash...) no difference. Also tried another OEM GM ICM and the SES light threw a code 42... UGH. So i went back to the aftermarket one.. Also sanded the surface under the ICM so its spotless.. no change... Now my belt tensioner rattles cuz i had to take the belt off to do the Crank Position Sensor.. Even made sure not to extended it all the way... guess it was weak.. Also, can spark plug wires really do this???? i cant see how they would stop the coil pack from firing.. Should i replace the plugs again? How can it be a fuel issue? Im out of ideas.. The ol girl might be heading to the yard.. frown Thanks!
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I think your belt tensioner rattles because your harmonic balancer is shot. C'mon, you just took it off. It'll come off easy the next time. AND THESE THINGS GO OUT ALL THE TIME on cieras.
Of course if a wire has an open or very high resistance it will not fire. You need to check that you are getting good spark out of both towers on each coil. Test at the coil or with a good known plug wire (you really should ground the other tower to take it's plug out of the loop). Spark at one tower and not the other of the same coil indicates the coil assuming you have verified plugs and wires are good. Also place a volt meter across the towers and see if resistance is in specs, same thing with wires and plugs they all have a maxium resitance spec. It seems you are throwing parts at this problem and it'd be cheaper to buy or borrow a service manual and follow the diagnostic chart or maybe take it to a good engine mechanic. A good one can usually find your problem within an hour and for about a $60 diagnositic fee.
It might be going to the shop.. scrap went down a little 190/ton. replaced the ign ctl mdl again, no change. ITS NOT THE ICM! lol. The first time must of been a freak thing or something.. you know, believe it or not, i do have the 2600 page factory service manual for this GM 3.3L, and it points to replace the ICM if spark does not fire from coil, even after switching in a known good one.. Coils are new... and im sorry, how can the Harmonic Balancer be shot? It is tight, and free of any wobble.. the rings are not bent, and the whole thing was just cleaned with dawn soap. How would i know if its shot? If i take a little tension off the tensioner with the car running, the sound goes away. you can also feel it in the ratchet. I might replace it away way though if im over looking something on it.. Alright, what started the original miss was when Irene hit.. you might know where im going with this.. the front of the car had water over the tires. BUT, the middle and rear were on dry land. The car was running when this happened... The road washed out, and a rut was in the middle of the road, & both front tires fell in to the water so in turn the car got stuck, and i had to leave it for hours.. When all was said and done, water covered everything below front 3 cyls.. I replaced the coils and ICM, and i was set, NO problems till recent... I did switch in known good coils, no go.. Im pretty sure tomorrow im going to call a shop, and see what they say.. frown thankss.
I just remembered an incident some years ago with a Ciera of this vintage. It was doing similar to what you describe, i had someone crank it while i played with the wiring. when i moved the wiring harness on the ICM the thing fired right up and ran perfectly, one of the terminals was loose in the connector. Quick and easy to check.
Post your symptoms on http://www.a-body.net/forums/index.php There's a forum for everything!!! I like the guy who put a 5 speed stick shift in his early 80s diesel buick century. What's got me thinking it's your spark pickup is how your coil packs are sparking for one cylinder but not the other. That spark energy goes through both spark plugs each time, so the coils are, IMO, good. This leaves, again IMO, something not telling the "device with authority (ICM)" that it's time for the missing cyl to fire. Something with a unique "switch" for each of six cylinders. Like a wobbling tone ring inside a shot harmonic balancer. If you submerged it quickly in water it could have warped the metal.. they're cast iron, right? Take a hot fry pan and throw it in the sink, it won't sit right on the stove anymore after that. This sounds like something someone with a 'scope might find; shops with a tech that can use one are few and far between. But if he watches the waveform coming off the crank pickup he might spot an abnormality.
Hey. So i was testing the OHMS of the sparkplug wires, (seemed high, at 15-19K) as i was taking the front most left cylinder wire off, the center stayed on the plug.. I just had these pulgs off a couple of weeks ago to install new ACdelco plugs.. hummm... maybe these wires are gone... But they only have around 35K miles, or 8 months. Well now they are shot because the front one pulled apart.. I am going to get new ones today. They will be Auotlite professional.. same as old. To note, i do have WEAK orange spark...... I thought i had NO spark... High resistance in the wires? ugh ill kick my self as i assumed something simple could not be the problem.. Ill post of A body later tonight. I called 2 shops and they could not help me because they said Oh wow, thats old.. LOL. Thanks!
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Ok, this is different, sounds like a coil or plug wire problem, not a control issue. If the crank sensor or balancer went out your spark would be bright blue if it worked. Why not move your coils around? They're interchangeable, except for the numbers painted on them. If the problem follows the coil, there you go. If it doesn't, it's the ICM. Plug wire resistance is not a big deal at 10's of kilovolts. It's there for radio noise suppression. An actually internally broken wire might give you issues. Autolite pro= advance auto stuff with coupon? laugh I tuned my truck up with that stuff in April and it barely runs in the rain, it may not be up to snuff for you or me, I'm thinking.
So spark plug wires are a No go.. the whole ignition system has been replaced. Autolite professional wires + paste $23.XX Code was 10$ off 30.. geeeeeeeeeeeee. :D:D:D:D KNOCK SENSOR? can that take out spark? moved coils around.. you would never know. same ones dead/ weak spark.
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