Grinding, No start and backpressure through the intake
Thread Starter
|
Joined: Apr 2021
Posts: 3
Grinding, No start and backpressure through the intake
Hello everyone. I've been working on cars for a minute and have myself pretty stumped. I'm a "driveway certified mechanic" but am totally in over my head with this one.
About the car first, its an 02 monte carlo ss 3.8L naturally aspirated. I have an empty upper intake manifold, exhaust work, a pcm tune (zzp) and that is it.
About a week ago it started to make a sound that almost sounded like the starter grinding but the car would start and run fine once started. Fast forward to this weekend, I thought I had a leak from the crank seal so i pulled that out and replaced the crank seal. I looked at the starter and didn't notice any deformation on it as if it were grinding. Slapped everything back together and now am getting a horrible grinding or metal on metal sound, no start and when I get off the starter ( un-turn the key) I can hear pressure release from through the intake and can smell a bit of gas mixed with exhaust or almost like a super rich burning exhaust. I pulled the front three spark plugs (didn't have time to pull the rear three) and 2 of them had normal gap, but smelled like gas. The third was gapped to about .05 and also smelled like gas. When it was running, it ran fine and strong and had no issues at idle or while running. I drained all the oil and it has no coolant or metal flakes in it.
At this point I am at a loss and am reaching out to the people who may and do have more knowledge than me to get this issue resolved. If anyone has anything I should try or any tips as to where to start please let me know. Any help is greatly appreciated as the car is taking up the garage and I am borrowing a family members car until the monte is running again.
Again thanks in advance for any input.
About the car first, its an 02 monte carlo ss 3.8L naturally aspirated. I have an empty upper intake manifold, exhaust work, a pcm tune (zzp) and that is it.
About a week ago it started to make a sound that almost sounded like the starter grinding but the car would start and run fine once started. Fast forward to this weekend, I thought I had a leak from the crank seal so i pulled that out and replaced the crank seal. I looked at the starter and didn't notice any deformation on it as if it were grinding. Slapped everything back together and now am getting a horrible grinding or metal on metal sound, no start and when I get off the starter ( un-turn the key) I can hear pressure release from through the intake and can smell a bit of gas mixed with exhaust or almost like a super rich burning exhaust. I pulled the front three spark plugs (didn't have time to pull the rear three) and 2 of them had normal gap, but smelled like gas. The third was gapped to about .05 and also smelled like gas. When it was running, it ran fine and strong and had no issues at idle or while running. I drained all the oil and it has no coolant or metal flakes in it.
At this point I am at a loss and am reaching out to the people who may and do have more knowledge than me to get this issue resolved. If anyone has anything I should try or any tips as to where to start please let me know. Any help is greatly appreciated as the car is taking up the garage and I am borrowing a family members car until the monte is running again.
Again thanks in advance for any input.
Joined: Feb 2008
Posts: 6,465
So the only thing you changed between running to not running is the crank seal replacement?
I'd probably start in that area to see if anything looks odd. Not much in that area besides the crank sensor, but I'd check to make sure it's still plugged in and the wires didn't get damaged as that is pretty critical to function.
As for the grinding, I'd probably stick a ratchet on the crank bolt and start turning the engine over to see of you can isolate which area its coming from (or if it spins easily / cleanly, indicating that the noise may only occur with the starter engaged).
The one thing I'd check is to pull the inspection cover off the bottom of the trans and try to inspect the flexplate for cracks. Maybe its cracked bad enough that a chunk is dragging on something? Shouldn't cause a no start though unless the whole outer ring sheared off which ive never seen before.
I'd probably start in that area to see if anything looks odd. Not much in that area besides the crank sensor, but I'd check to make sure it's still plugged in and the wires didn't get damaged as that is pretty critical to function.
As for the grinding, I'd probably stick a ratchet on the crank bolt and start turning the engine over to see of you can isolate which area its coming from (or if it spins easily / cleanly, indicating that the noise may only occur with the starter engaged).
The one thing I'd check is to pull the inspection cover off the bottom of the trans and try to inspect the flexplate for cracks. Maybe its cracked bad enough that a chunk is dragging on something? Shouldn't cause a no start though unless the whole outer ring sheared off which ive never seen before.
Thread
Thread Starter
Forum
Replies
Last Post