Symptoms of Ignition Module failure?

[wile2k]

As part of troubleshooting a rough running condition on my 86 T-Type, we hooked an inductive timing light to each spark plug wire and noted the flashes when idle and when revving. We noticed that when revving a couple cylinders would cut out completely and were somewhat flaky at idle, AHA!!

I don't have someone to swap parts with so I'm stuck buying new stuff and I started with the coil pack. Replaced that and the problem still persists. My next in line was going to be the Ignition Module (I assume that is what it is that is under the coil pack), but dont want to spend the money if it for sure isn't the problem. There appears to be a ground on the rear of the passenger head, is this the ground for the ignition module? It looks solid on my car.

Any other ideas on what could cause this? Definatly cyl misfiring and it is causing a whole host of problems for me. We have been troubleshooting for a week now and pretty much ruled out everything other than electrical ignition issues.

Anything else I can try or test?

Thanks,

Tom

 

[bishir]

As part of troubleshooting a rough running condition on my 86 T-Type, we hooked an inductive timing light to each spark plug wire and noted the flashes when idle and when revving. We noticed that when revving a couple cylinders would cut out completely and were somewhat flaky at idle, AHA!!

I don't have someone to swap parts with so I'm stuck buying new stuff and I started with the coil pack. Replaced that and the problem still persists. My next in line was going to be the Ignition Module (I assume that is what it is that is under the coil pack), but dont want to spend the money if it for sure isn't the problem. There appears to be a ground on the rear of the passenger head, is this the ground for the ignition module? It looks solid on my car.

Any other ideas on what could cause this? Definatly cyl misfiring and it is causing a whole host of problems for me. We have been troubleshooting for a week now and pretty much ruled out everything other than electrical ignition issues.

Anything else I can try or test?

Thanks,

Tom

First of all you could have the module tested at a parts store. Around here the O Riley's Auto Parts does it, but Autozone can too if they know how to work the machine. It will probably come back fine though if it's intermediate, but might be worth a shot. You could also try to remove the coil pack from the module if it's just one cylinder misfiring and use the wires feeding a known good side of the pack with the one thats feeding the missing cylinder. Then remove all the other plug wires and just crank the car to see if its firing fine. If it fires fine then the coil pack is probably good and you've narrowed it to the module. I don't think it's this, but you could unplug the cam sensor after the car has started and it should be in batch fire mode then you test again and if it's fine it could be the sensor.

Also, if you plan on owning these cars awhile Casper Electonics sells a coil pack/ module tester. Pricy but pretty cool.

 

[pacecarta]

aside from bad wires there is the coilpack/ign module and the crank sensor

caspers ignition simulator allows you to test the coilpack and the module it will simulate up to 8k rpm,
if it misses on one coil , remove the coilpack and swap ign module wires from bad coil with one that was good (swap around the green blue yellow wires)
if the miss is on same coil its the coil pack, if it moved to another coil its the ignition module

and if if that checks out ok you you can test the wires and plugs , leave the plug wires connected at coil pack , pull plugs from engine and install in wires install the plugs into a grounded bar and with simulator you can visually check each plug for good spark
for this rest i drilled and tapped a 3/8 bar of aluminum for the plugs to screw into and lay it on the alternator for the ground .

cranks sensor should be checked for clearance and rubbing ,

 

[wile2k]

Thanks all for the pointers. I really appreciate the help, this is such a frustrating thing to troubleshoot.

I'll play with the coil some more tomorrow, I wish I knew someone local that I could swap coil/ign modules with to be sure that is the problem. Dang things are pricy as hell to buy local and I'm just out time if I order one in.

Can someone explain to me the role that cam / crank sensors play in generating the spark? I can't seem to find it explained in simple terms, just a bit here and bit there that usually has some contradiction to it lol.

Thanks again for your responses.

Tom.

 

[pacecarta]

cam sensor sets up the firing for the injector to be timed correctly with the cylinder about to be compressed and is triggered once per every two engine rotatation so sometimes it takes a couple turns to trip it so injector sequence can begin
you only need cam sensor for startup to get engine run , if it is unplugged it will still run in batch fire mode (all injectors fire instead of just the one on the cylinder that the engine is about to compress ) but wont restart , if your cam sesor dies you wont have injector pulse
common failure is the interuptor ring under the cap is wobbled and hitting the sensor in the or interuptor ring tab broke and its loose and the shaft spins but ring is in wrong place , or the cap itself which is the sensor is no good and needs replacement (improper adjustment will also cause problems)

the crank sensor is responsible for the spark event and is triggered three times per engine rotation .
you need crank sensor signal at all times when engine is being cranked and when its running . if you have no crank sensor signal you wont have injectors either since module needs it to be present first
common failure is an out of round balancer interupter ring or loose wobbling balancer that causes the interuptor ring to contact the sensor and either break it or cause it to misread the actual window position since its a magnetic hall effect trigger (improper adjustment will also cause problems)

contact jeremy woods and get the cdrom of the buick turbo service manual

and save these to your favorites and read them
http://www.vortexbuicks-etc.com/
www.gnttype.org

 

[wile2k]

cam sensor sets up the firing for the injector to be timed correctly with the cylinder about to be compressed and is triggered once per every two engine rotatation so sometimes it takes a couple turns to trip it so injector sequence can begin
you only need cam sensor for startup to get engine run , if it is unplugged it will still run in batch fire mode (all injectors fire instead of just the one on the cylinder that the engine is about to compress ) but wont restart , if your cam sesor dies you wont have injector pulse
common failure is the interuptor ring under the cap is wobbled and hitting the sensor in the or interuptor ring tab broke and its loose and the shaft spins but ring is in wrong place , or the cap itself which is the sensor is no good and needs replacement (improper adjustment will also cause problems)

the crank sensor is responsible for the spark event and is triggered three times per engine rotation .
you need crank sensor signal at all times when engine is being cranked and when its running . if you have no crank sensor signal you wont have injectors either since module needs it to be present first
common failure is an out of round balancer interupter ring or loose wobbling balancer that causes the interuptor ring to contact the sensor and either break it or cause it to misread the actual window position since its a magnetic hall effect trigger (improper adjustment will also cause problems)

contact jeremy woods and get the cdrom of the buick turbo service manual

and save these to your favorites and read them
http://www.vortexbuicks-etc.com/
www.gnttype.org

Sweet, thanks Paul, very helpful. I was wondering where to get a service manual, I'll have to do that.

With my symptoms it doesnt make sense that it would be either cam or crank sensor then. I'll see if I can get my hands on an ign module to test with today.

Thanks again.

 

[GNRick]

Two reasons to bite the bullet and buy an ignition module ($180 from GMParts Direct) and a coil pack ($55 from Kirban);


The price is only going to increase

You will need them sooner or later

 

[1turbo6]

did you get this fixed? I am having similar issues and was wondering if changed the module?

 

[wile2k]

It took the ignition module to shore up the weak spark. It didn't fix my problem though as I have a couple wiped cam lobes that are causing failure on one cyl. The weak spark just happened to be a coincidence.

 

[Turbotime]

I have a code 42. I was told this is probably a ignition module problem. What do the rest of you think? Should I change the coil pack at the same time? Is the brand STANDARD or Wells ignition module ok to use? THANKS

 

[TurboBuRick]

Allot of guy's say to replace the cp and module together.

As far as the brand, AC Delco only.

 

[Toddmc66]

My problem is similar. I was dropping two cylinders after about 5 miles of driving and all of a sudden they would come back online. It was my MSD box. I removed it and replaced the ignition module and coil for good measure. After a good one hr drive I shut off the engine with no problems. Went to start it in the morning and no spark. I've gone through 3 new modules and tried another new coil.... NO SPARK. If I put the original module back in it has fire but it won't start, sounds like its out of time.

 

[John Larkin]

This may sound overly simple but are the plug wires in the right order? After that many swaps it is possible to miss something. Also the wires that connect between the module to the coil pack obviously have to be correct as well. The common blue wire goes to all three even cylinders. The others should be Blue 3. green 5 and yellow 1. Just a thought. http://www.installationinstructions.com/FYI/ccci-info.pdf

 

[jckcolarusso]

Sounds like cam sensor reluctor ring moved but most of the time no spark is crank sensor

 

[Toddmc66]

Well it was the cam sensor reluctor. I passed it up because the sensor tested good. I removed the reluctor and found the positioning tab broke off. I moved it to the correct position and it fired right up. Just ordered a new billet aluminum reluctor from RJC Racing. Thanks for the help.

 

[Toddmc66]

Installed new cam reluctor kit from RJC Racing and all's good, thanks for the input.