Question : Replace Ignition Coil For Preventative Maintenance

[83ste]

I've got an 83 2.8 LH7 Z code and wondering the coil should be replaced as preventative maintenance. I think all 82- 84 2.8 coils are the same single coil HEI/EST. The is original OEM so it's old time-wise even with 73K miles. There are no misfires and coil resistance on primary and secondary meets specs. I know the resistance does not tell the whole story on coil condition, though. Do these this GM coils fail have a typical failure mode? I have some that go bad with a partial failure and others that go out all at once. Brand recommendation if it should be replaced (Standard)?

[IDCavalier]

Boy, IDK. I can't speak to the distributor engines, but I know that once I started changing ignition parts, I have had nothing but trouble.

Maybe buy one as a backup, and keep it in the vehicle?

I have heard that AC Delco is the most reliable coil. I like BWD Select myself, but my car won't run due to ICM failure!!!

Good luck!

[83ste]

The coil on my other car just died at 11 PM and I needed a tow. I was not to far from home and in a good area luckily. One small misfire and then it just died after the restart so, it seems like keeping a spare in the vehicle it is the thing to do. I will replace it with a Standard Intermotor part and see how it does.

I think on newer cars the coils and the computer related parts are more critical as far as specs. But reliability with parts nowadays seems like a crap shoot. I am pretty sure BWD is a Standard brand, but of course that does not guaranty the quality as Standard/BWD both have a several quality levels .

[Purple pit]

Yes they do now. So get the top end BWD and you should be fine. There is a control module under the cap. When that goes the engine will die and there is no restart. I'd say that is the problem, but a back up coil is always nice to have. Be sure to get one with the same color wires as your stock one. If you don't it will quit working quickly.
The control module should have four electrical connections, two on each side. It's been a long time, please take a photo of it before you take it off for me.

[pontiacmc]

If this is HEI distributor there is no Ignition Module under the cap, that started in 86 I believe. BWD in my opinion sucks, if you are going with new ignition parts try and get Delco, anything else just doesn't last. Oh and HEI coils all inner change. You could go get the Accel Super HEI coil off Orielys shelf and be set.

[IDCavalier]

If the ICM isn't under the cap, then where is it?

I had a 1976 Chevy (small block, of course) and it had an ICM under the cap.

Where did they put them on 660s?

[pontiacmc]

sorry my mistake, I was thinking of the external 2 plug in ICM from the late 80s. You are right, there is the 4 prong ICM under the cap. Cant say I have seen them go bad very often but still can happen. They also are interchangeable.

[83ste]

I am also pretty there is a 4 pin ICM under the cap. This is an HEI/EST ignition that uses a single separate ign coil with a 4 pin connector on the primary side. BTW, this had Computer Command Control (C3) system and was early version of ODBI, which sent the ignition signal from ECM to the ICM. I believe that the S-10 verison of the 2.8L did not use C3, so it had a different distributor. I am not sure about the coils. Anyway, attached are pics of the distributor and coil, I am not advocating any brand, just a pics for reference.

http://shop.advanceautoparts.com/web...5034|L3*16064#

http://shop.advanceautoparts.com/web...14923|L2*15034

[Purple pit]

Replace that ICM. A few people I knew had them go out(I never did) on V8's. One of my friends had a distributor like that on a 90 something 2.8 in a Firebird. Man did that thing run!

[Futures Passed]

On the topic of getting new coils, I've seen a lot of people return the base level BWD coils, but not due to BWD's fault. Some people will buy the cheapest coil they can get, put it on their car, and try to return the coil ("I didn't need it.") after they've cleaned it up. This gets by a lot of people that work the counter, especially when it gets returned without a duplicate in stock to compare it to.

BWD Select is nice since they make them gray (most of the time) and have better contact point materials. You should be able to tell right away if it has been swapped out for a junk coil. Basic BWD coils are great, as long as that's what is actually in the box.

[davida1_hiwaay_net]

On the topic of getting new coils, I've seen a lot of people return the base level BWD coils, but not due to BWD's fault. Some people will buy the cheapest coil they can get, put it on their car, and try to return the coil ("I didn't need it.") after they've cleaned it up. This gets by a lot of people that work the counter, especially when it gets returned without a duplicate in stock to compare it to.

BWD Select is nice since they make them gray (most of the time) and have better contact point materials. You should be able to tell right away if it has been swapped out for a junk coil. Basic BWD coils are great, as long as that's what is actually in the box.

I 've had issues with BWD Select coils. I installed 3 new ones when I was fighting a missfire issue. It corrected the problem 6 months ago. Then last week my car developed a miss under boost, and I noticed one of the 6 month old BWD Select coils was cracking around the terminals. Thankfully, Advance Auto graciously replaced it.

It looked like the coil resin had shrunk and cracked.

I hear ya about the returned parts. Always inspect things BEFORE LEAVING THE STORE so that if a sham item is in the box, there's no doubt it was nothing I did. I've found a 3800 crank sensor which was only the bracket and no sensor head; connecting rod bearings that were dirty, corroded, and gouged and appeared as if they had been installed and removed; as well as many ignition modules which had signs of installation (bolt marks and thermal grease). Thankfully I caught these before leaving the store.

That is the trouble with DIY stores dealing with the "general public."

[IDCavalier]

I had cracking around my terminals too! When my ICM went out (again) about a year ago, I saw cracks on two of my 3 coils (DIS).
My 93 Caprice Police Car had that same ignition system as in the pics. I believe MSD and Accel also make coils of that variety.

[davida1_hiwaay_net]

Here is a post from a-body.net which may help here. This is a Buick engine, with the bolt-on DIS module connector. The terminals are identical to the ones in the connectors for the 60°V6 DIS, so the same damage could happen. It seemed like DIS modules kept failing again and again, but it was just the connector. Removing and reinstalling the connector would "disturb" the damaged contacts and it would work again - for a little while. This was shortly after I got the car and hadn't found all the gremlins in it yet!

About a month ago, my 1987 Century Turbo Sedan, with LG3 3.8 SFI engine quit running about a mile from home. It was just like the key was cut off. It seemed like an ignition issue. There were no codes and the laptop diagnostics didn't reveal anything unusual in the real-time sensor readings.

I tried swapping out ignition parts from another running car. I swapped the DIS module/coil assembly; crank sensor, cam sensor, and ECM/chip assembly. Nothing would make it spark. The parts from this car were put on the other car, and it ran normally.

Fast-forward to today, after a month of being out of town and other distractions. I got the engine started and finally determined that moving the harness near the firewall would provoke it to stall. The trouble ended up being the terminals in the connector where the harness plugs into the DIS module. This has the Magnavox DIS with the small screw in the middle of the connector. These terminals were "forced open" wider than they are supposed to be, preventing them from gripping the pins in the DIS module. It appeared that someone had forced an electrical tester probe into each terminal and damaged them.

It took about 5 minutes to fix, after LOTS of head-scratching, testing, reading diagrams, and shotgun-style parts swapping. Sometimes the simplest things trip us up. Just a reminder not to force a tester probe into that style of Delphi terminal. And you never know what the previous repairs have done to a used car.

Thanks,
David

Here are pictures explaining this fix for a faulty ignition module connector caused by loss of pin tension. Applies to all engines with DIS and bolt-on connector.













Sincerely,
David

[IDCavalier]

WOW! Thanks David!

That is AWESOME how you fixed that yourself! Turns out, that is EXACTLY what was wrong with my system.

But I just now got it fixed...where were you when people were battling over whether to use thermal paste?? LOL

I have noticed, however, that the 60 degree V6 (BTW- How did you put the degree symbol in your post?) IS a different harness (3 of them, actually) than the 3.8.
DSC01945.JPG


BUT, it WAS the exact same problem! Too bad that I spent all the money and time to buy and solder new new harnesses instead! On my two pin harness, the connectors were so deformed that I doubt I could have repaired THAT one.

I applaud your ingenuity in your method of repair!

Thanks again for your detailed post!


All the Best!

[davida1_hiwaay_net]

WOW! Thanks David!

That is AWESOME how you fixed that yourself! Turns out, that is EXACTLY what was wrong with my system.

But I just now got it fixed...where were you when people were battling over whether to use thermal paste?? LOL

I have noticed, however, that the 60 degree V6 (BTW- How did you put the degree symbol in your post?) IS a different harness (3 of them, actually) than the 3.8.
[ATTACH=CONFIG]7800[/ATTACH]


BUT, it WAS the exact same problem! Too bad that I spent all the money and time to buy and solder new new harnesses instead! On my two pin harness, the connectors were so deformed that I doubt I could have repaired THAT one.

I applaud your ingenuity in your method of repair!

Thanks again for your detailed post!


All the Best!

Thanks for the comments! Growing up in a family who was conservative with money tought me to find ways to fix things without buying stuff, whenever possible.

But yeah that one looks kind of past repairing. You were probably better off with a new one.

As for the thermal paste... LOL I don't like arguments so I wouldn't have been interested in reading that. Thermal paste has its place, and is called for by the factory for certain things, like HEI distributor modules. There are other products (dielectric gel) for connectors. They help keep corrosion at bay if the connector was clean and new when it was applied and not already corroded.