97 Corvette, dead cylinders on the back half

rockthemullet

rockthemullet

Forum Member
Alright guys, I've got a tough one. LS1 corvette, ran out of gas (may be related) one night due to a faulty level sender. Next day it dropped cylinders, I've been able to identify cyls 5, 6, and 8.. possibly 7.

- Pulled the injectors, soaked them, cleaned the rails. Rail pressure is solid, I've got a gauge in the car.
- Verified injector harnesses are sending signal. Fired up, same problem.
- Swapped a known good injector/coil to a known bad cyl, issue didn't move.
- New plugs, new wires, no change. ...
- Spot checked compression, Cyl 2 is ~180psi, Cyl 6 (bad) is ~170psi

I have compression, spark, and fuel... But I can hold my finger on the header primary tube on the dead cylinders while it's running.

LS1 short, LS6 heads, Comp cam, P1SC on 8psi, 60# injectors, TR6 plugs gapped at 35, full non-catted exhaust

I'm lost, any ideas? Would the rear knock sensor failing cause only the back half to malfunction? Would a valvetrain issue have cold compression but not seat the valves while it's running? ECU?

Any help would be greatly appreciated
 
I had an issue similiar once.....it was broken camshaft. The back 4 cylinders wouln't fire.....took the valve covers off and no valve train movement on those cylinders.

Yours probably isn't this, but its weird that the cylinders don't get hot.
 
Can sensor is in the rear of a 97. 02's read lean? Did you blow thru the rail at those injectors when you cleaned it
 
98 Camaro said:
I had an issue similiar once.....it was broken camshaft. The back 4 cylinders wouln't fire.....took the valve covers off and no valve train movement on those cylinders.

Yours probably isn't this, but its weird that the cylinders don't get hot.
Click to expand...

Next step is pulling the valve covers and then the intake, so I guess we'll see. It's a Comp 228 cam and I wasn't driving erratically (on the way to work) so I'd be surprised if that was the case

1BADAIR said:
Can sensor is in the rear of a 97. 02's read lean? Did you blow thru the rail at those injectors when you cleaned it
Click to expand...

I cleaned the rail and there's definitely pressure at the rear injectors because I cut the o-ring on 6 and knew it immediately. Scanner goes on it tonight (couldn't pull it from another car until today) so I should have a lot more to go on. If that's not conclusive, then I'm digging into the motor
 


Cylinder 7. Now I need to find a spring compressor and figure out if these are stock or aftermarket (PO installed the heads)
 
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