Question for TGP drivers.

[jman093]

I have a question for those who have spent a lot of miles behind a TGP. Have you had a lot of problems with the ignition system, namely the ignition module and coil packs? Or is it just me?

 

For the last 3+ years now I have exclusively driven two different TGPs. Both had ICM/coil pack issues when I bought them. I fixed both up fine and both have had issues with the new parts failing again a year or so later. In the past, the issue has been misfiring from one or two coils: misfiring when hot, misfiring under load, or misfiring all the time.

 

This latest issue was different though. The red car which got a brand new ACDelco ignition module and 3 new ACDelco coil packs a little over a year ago. Starting a couple weeks ago, it would run perfectly fine until about 50% throttle and higher, then it would very suddenly bog like mad. No misfire, but it would just have no power, the engine wouldn't want rev past ~3500rpm, and boost pressure would spike. It felt all the world like a weak spark issue sometimes called "spark blow-out." After confirming fuel pressure was good (~52psi under heavy boost), I threw on a set of the allegedly higher-power "blue-bottom" coil packs from a spare L32 I have in the garage. Sure enough the car pulls hard again and pulls hard all the way to redline.

 

I've owned a lot of GM 60V6 and 90V6 engines, and wrenched on hundreds more, and although I've seen plenty of coil packs and ignition modules fail here and there, I've never seen anything like the temperamental nature of the ignition system of my TGPs. And that makes me wonder if the stock system is rather weak for a boosted application (especially one making more boost than stock like my red car does) and the slightest decline in output leads to issues.

 

So I'm just curious to hear if other long-time TGP drivers are in the same boat. How has your car done?

[digitaloutsider]

Gen II 6/60s tend to eat coil packs as they get older because of their proximity to the exhaust manifold.  The ignition system isn't weak as these coils are driving plenty of 350+ HP 3800s.  The parts just get old and baked and it does them in.

[GOT2B GM]

Perhaps the added heat of having a turbo underhood accelerates the degradation of the coil packs. As stated, they are in a bad location for heat soak.

 

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[redgrandprix]

Ive put around 40k miles on my tgp and i had 1 coil pack go out but it was a msd i believe. Swapped out for ac delcos and taylor wires. Havent had an issue since

 

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[GabsOlds]

Relocation of the coils in order?

[jman093]

Relocation of the coils in order?

 

No, they are in the same spot on a TGP as every NA 3.1 that do not have my issues. If anything, a TGP has lower underhood temps because of the hood vents. Those really work.

[EMNCFI]

I have never had a coil problem, I think I have replaced them once, have owned my TGP since 1997, so I have a few hours behind the wheel

[Mach 5]

I have always kept spares in my car........ for obvious reasons... the failure rate of the new parts is substantially greater..... I cant figure it out myself.....

[jman093]

I have always kept spares in my car........ for obvious reasons... the failure rate of the new parts is substantially greater..... I cant figure it out myself.....

 

Are you using new GM ones as well? If so, are they the L67/L32 "blue-bottoms" or regulars?

[Imp558]

I wonder if there's a difference in the population of hydhydrocarbons in the cylinders with a turbo? Shorter coil lifespan may have something to do with allowable efficiency of the spark working the secondary windings harder.

[mfewtrail]

I've never had to replace a coil or ignition module on my TGP's. I do know the ignition module was changed on the Red one somewhere around 2007 though. I have no idea what was put on it then, but it's still fine today. The white non-turbo GP I have still has the original coils on it with like 270K on them, the original icm died around 245,000 I think. The Regal might have the original coils and icm as well at around 220K miles. I know they haven't been touched in the last 130,000 miles anyway. I assume they are original because they're numbered and I don't recall ever seeing replacement sets even straight from the GM dealers way back with the numbers on them.

 

I'm willing to bet the quality of the replacements has a lot to do with the durability of the parts these days. Where did you pick up your ac delco replacements? If you still by any chance have the packaging, post the country of origin on them. I think the old ones were likely from Mexico. Some of them were made in China later on for sure. I have no idea where they're made now. I would attempt to find older stock ones though. Looking through ebay listings, there are a few that list Mexico as the country of origin. If those are accurate, that's what I would purchase. If I pull a coil off for any reason, I'll try to see if they have a country of origin on them...though I don't recall any ever having that.

Edited March 28, 2017 by mfewtrail

[55trucker]

If the close proximity of the coils to the front manifold is a concern try wrapping that manifold in header wrap. I did this to the front manifold & the crossover on my DOHC engine to cut down on the heat being generated from them, during the summer with the A/C running the engine bay just cooks when the vehicle is moving slowly (rad fans running) seeing as there is nowhere for the heat to escape to due to the large footprint that the engine takes up. 

[Mach 5]

originally stock.. then I went to msd coils... but I may go back or switch ignition systems.... getting tired of swapping them... once a year. when the car runs............

[jman093]

I've never had to replace a coil or ignition module on my TGP's. I do know the ignition module was changed on the Red one somewhere around 2007 though. I have no idea what was put on it then, but it's still fine today. The white non-turbo GP I have still has the original coils on it with like 270K on them, the original icm died around 245,000 I think. The Regal might have the original coils and icm as well at around 220K miles. I know they haven't been touched in the last 130,000 miles anyway. I assume they are original because they're numbered and I don't recall ever seeing replacement sets even straight from the GM dealers way back with the numbers on them.

 

I'm willing to bet the quality of the replacements has a lot to do with the durability of the parts these days. Where did you pick up your ac delco replacements? If you still by any chance have the packaging, post the country of origin on them. I think the old ones were likely from Mexico. Some of them were made in China later on for sure. I have no idea where they're made now. I would attempt to find older stock ones though. Looking through ebay listings, there are a few that list Mexico as the country of origin. If those are accurate, that's what I would purchase. If I pull a coil off for any reason, I'll try to see if they have a country of origin on them...though I don't recall any ever having that.

 

Yeah, I've looked for the original numbered ones as well with little luck. They seemed to only offer the unnumbered ones through the parts counter and I do wonder if they're otherwise identical. I don't have any packaging unfortunately. It's been some months since I've last changed any besides the ones I'm talking about currently, which I stole from an L32 I have in the garage, so no packaging. The original numbered ones lasted well 125,000 on the red car, and 225,000 on the black one, but each went through a set in about 20,000 or so after that. I guess I have to either be fighting dumb luck or the ACDelco replacement coils aren't as good as the factory ones. I'll probably stick with blue bottom ones if any more fail and see if that does it.

 

 

If the close proximity of the coils to the front manifold is a concern try wrapping that manifold in header wrap. I did this to the front manifold & the crossover on my DOHC engine to cut down on the heat being generated from them, during the summer with the A/C running the engine bay just cooks when the vehicle is moving slowly (rad fans running) seeing as there is nowhere for the heat to escape to due to the large footprint that the engine takes up. 

It's not a concern. If that was the issue, every w-body would eat coils like mad.

 

originally stock.. then I went to msd coils... but I may go back or switch ignition systems.... getting tired of swapping them... once a year. when the car runs............

You've had the same luck on stock and MSD?

[LukeZ34]

I had an issue like this with my old red 5 speed TGP (back in 2004). Kept trading out ICM's and coil packs and kept having the same problems. Turns out that I found some wires in the loom that runs between the front head and the water pump (pass. side) had rubbed the insulation off and were shorting out on each other. Cut/Soldered/wrapped those broken wires and the problem was gone. Not saying that's your problem, but wanted to share my experience in case it helps you troubleshoot any.