valter

Update: I am complete moron It looked like that #1 was missing, but the real problem was hidden under pass. side valvecover. This is what I found under it, everything already disassembled (except rocker):



Spring is in 3 pieces Pushrod is laying under valvecover, which definitely took a beating from it. Valve is still in head. I tried to move valve, and it moves fine. Rolled pushrod on glass - it's fine.
Question: do I have a very-very slight chance, that valve/piston/head/something_deeper are not damaged and it will be worth a try to put a just a new spring there???

Thank you!

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'97 TransAm, LT1, 105k miles. One day driving it to work, while accelerating (less then 3k rpm) from a stop I felt severe power loss, engine started to shake/miss badly. I managed to get to a parking lot, and it barely idled. I have a vacuum gauge always hooked up and it's readings started to fluctuate and was lower then usual. I was able to carefully drive it back to my house, and engine started to run better, but still felt like it dropped a cylinder. Strangely, vacuum readings stopped fluctuating and became almost normal. Shaking was almost gone too.
In the next days I replaced plugs/wires/opti (whole new GM unit), it runs better, but cylinder #1 is dead. You can unplug injector and there is no response.
Spark on #1 is excellent, I tried swapping injector, everything looks fine under valvecover, no broken springs/rockers, no valvetrain noises. What can it be, and what should I do next? Bad valve, rings, hole in a piston? Compression test?
One more thing: if you give it a gas now, sometimes it's popping from intake...
I appreciate any help!

powerslide350

Pop the valve cover off and give a good visual inspection. Turn the motor by hand if possible or have someone bump it to see if both valves are opening/ closing.

A compression test/ leak down test would also be a good starting point.

You might also pop the radiator cap and crank it up and see if your getting bubbles from a bad head gasket. Or you could do the reverse and put a pressure testor on the cooling system.

Hope this helps, Josh.

RUDEDOG

I would pull the valve cover and inspect then do a leakdown test on cyl 1 and go from there. If no problems are found then ring injector harness. Did you physically swap injectors or swap connectors? It could be a bad injector.

powerslide350

Ok I see now you inspected the valve terrain.

Another simple test would be to remove the oil fill cap and check for excessive blow by which could be due to a cracked piston/ bad ring.

But the popping out of the intake sounds to me like a valve terrain issue. i.e. exauhst valve not opening or the intake valve not fully closing.

valter

Thank you guys!
I physically swapped injectors, #1 is still dead. When I replaced opti, I drained all coolant and it was like new. Visually there is nothing wrong with valvetrain. No bubbles in radiator. I will remove oil fill cap. I hope it can be fixed without pulling engine, otherwise car will be for sale as-is I have almost no time to work on it and I know no trusted local shops

Tex95Z

You need to check to see if the injector is even firing, to do that go to your local parts store and pick up a NOID light. It should be around 6 dollars. Plugs into the injector harness and blinks if its firing.

valter

Good point! I tried to listen injectors tick with a screwdriver, but it's hard to tell over other noises. I just hope it is fuel; this car was never abused, always Mobil-1 every 3k miles, it would be a bummer if valve is chipped or a piston cracked Thank you!

Guest47904

Lift up the fuel rail and have someone crank it over to see if #1 injector is squirting.

Should have done a compression test back when you posted on the 30th.

valter

updated 1-st post