1 Cyl miss, out of ideas, might sell cheap..LOL

[lbszr]

Rock auto lists the 16163993.

[tccrab]

Originally Posted by lbszr

If you still might need an ecm I've saved these sites but haven't checked them out. Some have said the 95 will work in the 90, but I've heard it won't work also. If it would work Corvette Central has them for 95. Hope one of these helps.

Corvette Central has no stock.
Just called.

TomC
"Crabs"

[Spanky1965]

I will look, thanks

[Spanky1965]

oops...

[Tyler Townsley]

Having had a simular problem many years ago I can tell you the best way to troubleshoot and what the steps tell you. First what color is the spark plug tip?

1. Pull the # 6 plug wire put a spark plug in and lay it on the plenum and start the car. Look at the spark across the plug. Choose another cyl and do the same. If the spark across the gap is not the same you have a spark related problem in the # 6 cyl.

2. Given that the above is proved OK you then go to the fuel side. You can measure the resistance on the injector, if it is off then you have a bad injector. You can also swap the injector with say the #4 cyl and see if the miss follows the injector, if it does then you have found the problem. Given that you show the pass side lean then you probably have a bad primary side injector on # 6.

3. If neither of the above happens then you have what I had, a broken valve spring, mine was exhaust and took me 3 months to troubleshoot and diagnose. The only way you can verfy this is to pull the cam cover and cam and take out the spring, something I am not sure you can do with the head still on the car.

It would be EXTREMLY unusual for the dis or the ecm to only effect one cyl.

Tyler

[Spanky1965]

good call, but wouldn't a compression test show if a valve was not opening? I am asking?? I don't know

[Tyler Townsley]

Originally Posted by Spanky1965

good call, but wouldn't a compression test show if a valve was not opening? I am asking?? I don't know

No, what if effects is closing. It acts as a lazy closing that either keeps the exhaust open too long or the intake open too long, the cam lobe will open it no matter what the condition of the spring. A comprssion check rpm is too slow for it to effect the compression reading. I finally figured mine out from looking at the plug and elimination of everything else. IE I move plugs and the discoloration stayed with cyl 6, I moved injectors and the miss stayed with cyl 6. The spark was strong across the plug when I laid it on the plenum. The compression was good what was left? I actually did not put it togeather until I was talking to a friend about it and he mentioned that he had a simular problem on a BBC but he could see the spring was broken when he pulled the valve cover. He did say the compression was good, which had been the part of the puzzle that did not make sense to me until we talked about it.

Once I figured it out I even knew when and how it happened. I had been getting a trouble code for the shocks and I could clear it for awhile by turning the car and restarting, it would stay off for ablut 15 min or so. At first I would put in the clutch turn off the motor coast and start the car then let out the clutch. After awhile i just turned the car off left it in gear and turned it on and let it start. Bad move, with the LT 5 you have a wasted spark that fires whichever cyl has enough fuel, aparently there was enough fuel in the off cyl to fire it with a partially open exhaust valve and it broke the spring when it fired.
To this day I can remember it was running fine and I reached turned it off then back on and it was missing. It took 3/4 months to connect the dots.

Tyler

[Spanky1965]

wow, ok so if I pull the valve cover I cant see it? car only has 30,000 miles

[SharkPilot]

Tyler,

How does a valve spring get broken when the cylinder fires with the valve part way open? I'm not doubting you at all it just seems puzzling to me.
Does it send some sort of shock up the valve and stress the spring?

Thanks,
SharkPilot

[Pete]

Another thought came to mind.

Make sure the injector plug has seated right on the injector or did not mix up the secondary plug with the primary plug.

I know it sounds silly but sometimes it's the silly stuff that drive us nuts.

Pete