missing/rough running

[Roadster]

Great job Mark, I may have missed it, but what brand coils did you purchase?
Glad it's running better than you expected!!!!

[8cam]

Coils are AC Delco D555, perfect replacement. Only difference was they don't have the cylinder numbers on them, otherwise identical. I thought about marking them with a paint pen but I just wanted my car back together. Did I mention I'm happy? I couldn't stop grinning when I buried the throttle. What a difference. If my experience is anything to go by, everyone should replace their coils if original. They can go bad slowly and you won't notice the change, and the LT5 can tolerate a bad spark without feeling rough. Just amazing.

[mgbrv8]

Great job Mark I'm glad to hear she is up and running. Now go have fun and drive it like you stole it.

Dave Hetrick

[Roadster]

Originally Posted by 8cam

Coils are AC Delco D555, perfect replacement. Only difference was they don't have the cylinder numbers on them, otherwise identical. I thought about marking them with a paint pen but I just wanted my car back together. Did I mention I'm happy? I couldn't stop grinning when I buried the throttle. What a difference. If my experience is anything to go by, everyone should replace their coils if original. They can go bad slowly and you won't notice the change, and the LT5 can tolerate a bad spark without feeling rough. Just amazing.

I am starting to look at what will be needed whenever I get around to pulling the plenum, as the 74 needs more of my attention before the Z. I know some have used the coils from Accel with good results. So getting things here and there will have me prepared before I tackle that job.
So it appears like you are driving a different ZR-1 than what you did before!!! Lol........as you have mentioned, you are one happy guy. Yes, it is amazing that doing some of the "little" things can make such a drastic improvement.

[8cam]

I posted about this in my daily driving thread, but thought I'd tie this one off too. After pulling the plenum, replacing the coils, wires and plugs, my car ran just awesome...and then it didn't. It still pulled hard and strong, running smooth all the way to red line, but something popped and the idle skyrocketed, and the secondary transition was more of a step.

Apparently the plenum pull put some stress on the original throttle body gasket, and after a little running it decided enough was enough. It took a powder, and I had unmetered air coming in the intake. I KNEW I should have replaced them with the plenum pull dammit. So I decided to do it right, sent the TB to Marc for a rebuild and ordered new gaskets from Jerry. Finally got it back together yesterday - idle issues GONE, step transition GONE, totally smooth from idle to redline and with the new coils, pulls like a bat outta hell.

Tom go ahead and pull the plenum if you're thinking about it. It's really not that hard a job, just be methodical and you'll have it done quicker than you think. That link I posted is an excellent step-by-step tutorial, and it's honestly less than a 1 hour job easy.

[Roadster]

Originally Posted by 8cam

I posted about this in my daily driving thread, but thought I'd tie this one off too. After pulling the plenum, replacing the coils, wires and plugs, my car ran just awesome...and then it didn't. It still pulled hard and strong, running smooth all the way to red line, but something popped and the idle skyrocketed, and the secondary transition was more of a step.

Apparently the plenum pull put some stress on the original throttle body gasket, and after a little running it decided enough was enough. It took a powder, and I had unmetered air coming in the intake. I KNEW I should have replaced them with the plenum pull dammit. So I decided to do it right, sent the TB to Marc for a rebuild and ordered new gaskets from Jerry. Finally got it back together yesterday - idle issues GONE, step transition GONE, totally smooth from idle to redline and with the new coils, pulls like a bat outta hell.

Tom go ahead and pull the plenum if you're thinking about it. It's really not that hard a job, just be methodical and you'll have it done quicker than you think. That link I posted is an excellent step-by-step tutorial, and it's honestly less than a 1 hour job easy.

Wow, it's just like you said, that your Z is actually running better then when you purchased it.....you must be very satisfied with the way that is performing since all of the work is completed....

I know I have to do mine, just have to set aside time to get it done, although it runs great. I still have to purchase the parts needed, so that I've have everything ready to go. I may try to employ the WAZOO guys to help if possible sometime in the future. I understand that they work for food & drink....

When we were at the Corvette show back in September, I had showed David how my vacuum pump was disconnected. He and another member plugged the connector back into the pump and it just kept running. When they disconnected the vacuum liine that goes under the plenum, and put their finger over it, then the pump started working correctly. I don't know or understand what would cause that issue to happen. And I would imagine that my secondaries are "tied" or "wired" open as they work quite well. So when the "pull" does get done, it should answer alot of questions.......

I don't know Mark, but I still think that you just may be enjoying your ZR-1 a little bit more than your "308"

[8cam]

Originally Posted by Roadster

Wow, it's just like you said, that your Z is actually running better then when you purchased it.....you must be very satisfied with the way that is performing since all of the work is completed....

I know I have to do mine, just have to set aside time to get it done, although it runs great. I still have to purchase the parts needed, so that I've have everything ready to go. I may try to employ the WAZOO guys to help if possible sometime in the future. I understand that they work for food & drink....

When we were at the Corvette show back in September, I had showed David how my vacuum pump was disconnected. He and another member plugged the connector back into the pump and it just kept running. When they disconnected the vacuum liine that goes under the plenum, and put their finger over it, then the pump started working correctly. I don't know or understand what would cause that issue to happen. And I would imagine that my secondaries are "tied" or "wired" open as they work quite well. So when the "pull" does get done, it should answer alot of questions.......

It really is running better than ever, really a startling difference. My car sat in a warehouse for more than a decade and that neglect just isn't good for anything. By driving and fixing, I've been addressing all those things and now I suspect I'm driving a Z that feels like it did when it was new. Smooth, powerful, and pulls easily well beyond 7000 rpm.

Sounds like you have a vacuum leak somewhere under the plenum. When you can plug the pump line and it cycles off, your pump is fine. If there's a leak, it can't build the proper vacuum and just runs and runs. The pump is really only necessary at low rpm where the engine itself isn't pulling enough vacuum. When the rpms rise, the engine builds the vacuum and the secondaries work as they should, but the transition isn't as smooth as it should be.

Originally Posted by Roadster

I don't know Mark, but I still think that you just may be enjoying your ZR-1 a little bit more than your "308"

LOL I really do enjoy it a lot. I think my wife would rather I had a newer car with a warranty that didn't require care and feeding, but I enjoy this a lot more. A car should have some personality, and give you the chance to bond with it. I had an M3 before the Z and it was absolutely perfect in every way - smooth, powerful, handled beautifully, built like only the Germans can, absolutely stone-cold reliable, perfect. Perfectly boring. To me it was an appliance, albeit a beautifully built one, and I just never bonded with it.

The ZR-1 is that amazingly beautiful American girl who doesn't think she's "got it" but with a little encouragement, can knock out a room with one smile. It just so happens she's become good friends with a fiery Italian who sings opera and knows how to dance. I think they are good for each other.

[XfireZ51]

I believe thoroughbreds have a personality, a character to them. They have an ego. Watching the Belmont race scene from the movie Secretariat gives you that sense that Secretariat had finally had enough of Sham and decided to just blow him off. Just destroy him so there would never be a question. If it's possible mechanically, I think the ZR is one of those cars with that kind of character.
A bit snobby with that wide tail, not a boulevard cruiser and soooo much more fun at speed. Almost a "come on and try me" personality. I have always enjoyed having "sleepers". A modded ZR certainly fits that bill for me.

[Roadster]

Originally Posted by 8cam

It really is running better than ever, really a startling difference. My car sat in a warehouse for more than a decade and that neglect just isn't good for anything. By driving and fixing, I've been addressing all those things and now I suspect I'm driving a Z that feels like it did when it was new. Smooth, powerful, and pulls easily well beyond 7000 rpm.

Sounds like you have a vacuum leak somewhere under the plenum. When you can plug the pump line and it cycles off, your pump is fine. If there's a leak, it can't build the proper vacuum and just runs and runs. The pump is really only necessary at low rpm where the engine itself isn't pulling enough vacuum. When the rpms rise, the engine builds the vacuum and the secondaries work as they should, but the transition isn't as smooth as it should be.



LOL I really do enjoy it a lot. I think my wife would rather I had a newer car with a warranty that didn't require care and feeding, but I enjoy this a lot more. A car should have some personality, and give you the chance to bond with it. I had an M3 before the Z and it was absolutely perfect in every way - smooth, powerful, handled beautifully, built like only the Germans can, absolutely stone-cold reliable, perfect. Perfectly boring. To me it was an appliance, albeit a beautifully built one, and I just never bonded with it.

The ZR-1 is that amazingly beautiful American girl who doesn't think she's "got it" but with a little encouragement, can knock out a room with one smile. It just so happens she's become good friends with a fiery Italian who sings opera and knows how to dance. I think they are good for each other.

I have been lucky, it seems the more owners mine has had, the better....
I haven't had any "real problems" so far, other than replacing the clutch slave and master cylinder. I alway make sure that both the water temp and the oil temp are at operating temps before any hard acceleration. And I have to say, it has been smooth so far, but then again, I have only driven the Z about 2,000 miles in 7 1/2 months. So more driving is in order......

As far as the possible vacumm leak, I don't have a clue, simply because I don't understand and have alot to learn about the LT5. I have the books and the info from the forum, but no time, as least not the time needed to devote to learning. Maybe when I retire in 2 1/2 years.....

Well said on the comparision of the two....not only do they compliement each other, they were made to be together........
I think that you had said at one time, something in the order, that although they are similar in some ways, they are different.....

On a side note, two weeks ago on the PA pike, on my way back from my run, A 5th wheel pickup passed me with a new Ferrari F12Berlinetta on a car trailer. I couldn't believe my eyes. First time ever I saw a Ferrari being transported like that.....a very nice machine........

Originally Posted by XfireZ51

I believe thoroughbreds have a personality, a character to them. They have an ego. Watching the Belmont race scene from the movie Secretariat gives you that sense that Secretariat had finally had enough of Sham and decided to just blow him off. Just destroy him so there would never be a question. If it's possible mechanically, I think the ZR is one of those cars with that kind of character.
A bit snobby with that wide tail, not a boulevard cruiser and soooo much more fun at speed. Almost a "come on and try me" personality. I have always enjoyed having "sleepers". A modded ZR certainly fits that bill for me.

Also very well said, the simple joys of driving great performance vehicles, especially the ZR-1's....what more could you say!!!