Holy Moly!! - ZR-1 Net Registry Forums

SharkPilot · 09-21-2008

First, some background:

A few weeks ago I had a backfire. Following that I could not get the car to run right. The problem turned out to be injectors that were failing.
I replaced all 16 injectors with Accel units that I got from JeffVette.

Got those all installed and everything put back together. The engine ran great, most of the time. The idle would be very smooth and low speed running was just beautiful. Sometimes the idle was rough and there was a misfire at low speed. Up high it ran great and really took off. The fuel economy was poor too, running about 2 mpg less than before the injectors.

Today I decided to change the plugs. As I pulled them out they all looked pretty nice but the gaps were a bit excessive. I was thinking that the plugs may be on the worn side. The have about 10,000 miles on them.
Then I got to number 8. When I got that out I found that the center electrode and insulator are gone. Yes... gone! It's broken off about 0.5" above the ground electrode. It didn't happen upon removel either as the fracture face is blackened. This did not just happen.
These are Bosch Platinum plugs so they're not dime store cheapies. Has anyone ever seen this before?? And an even larger question... What did it do to my engine??
One good thing I guess is the ground electrode isn't bent or deformed so nothing hit it and clobbered it.

Edit: I just turned the engine over (backward from the alt. bolt) and the engine turned smoothly through about 1 1/4 revolutions. I did hear a small noise but it sounded like something in the front like timing chains or something.

Do any of you guys have any suggestions??

Thanks, SharkPilot

09-21-2008	#1
SharkPilot Join Date: Aug 2005 Location: Anaheim, California Posts: 105	Holy Moly!! First, some background: A few weeks ago I had a backfire. Following that I could not get the car to run right. The problem turned out to be injectors that were failing. I replaced all 16 injectors with Accel units that I got from JeffVette. Got those all installed and everything put back together. The engine ran great, most of the time. The idle would be very smooth and low speed running was just beautiful. Sometimes the idle was rough and there was a misfire at low speed. Up high it ran great and really took off. The fuel economy was poor too, running about 2 mpg less than before the injectors. Today I decided to change the plugs. As I pulled them out they all looked pretty nice but the gaps were a bit excessive. I was thinking that the plugs may be on the worn side. The have about 10,000 miles on them. Then I got to number 8. When I got that out I found that the center electrode and insulator are gone. Yes... gone! It's broken off about 0.5" above the ground electrode. It didn't happen upon removel either as the fracture face is blackened. This did not just happen. These are Bosch Platinum plugs so they're not dime store cheapies. Has anyone ever seen this before?? And an even larger question... What did it do to my engine?? One good thing I guess is the ground electrode isn't bent or deformed so nothing hit it and clobbered it. Edit: I just turned the engine over (backward from the alt. bolt) and the engine turned smoothly through about 1 1/4 revolutions. I did hear a small noise but it sounded like something in the front like timing chains or something. Do any of you guys have any suggestions?? Thanks, SharkPilot __________________ [CENTER][SIGPIC][/SIGPIC] 1991 ZR-1 #1135 Red/Red with both tops. Stock except for an open topped K&N filter.[/CENTER] Last edited by SharkPilot; 09-21-2008 at 10:16 PM.