Low compression in #3, #3 injector not working, etc.

[konvict1981]

Ok let's start off with I have a 2g block with 1g head. I was gone for a month in a half and my wife and a couple of friends that have a custom shop wanted to swap out my radiator hose because it was going bad. Well someone forgot to plug the fan in and drove it about 25 miles at interstate speed and she over heated. Well when i got home and I noticed that compression was going back through the cooling system. I tore the head down and replaced the head gasket thinking it blew. Well that fixed that problem but #3 cylinder isn't firing and the compression is around 85psi. When we did the test, the compression was going through the intake. Blocked that off and it starting going through the exhaust. Also that same injector isn't working. I'm going to check the wiring and see if that's it. I'm guessing if that doesn't work then it has to be a bad injector right? And could these two problems be related? Any help is going to be greatly appreciated. Thank you.

Almost forgot. Had to buy a new timing belt tensioner. Put that on and it still seems like it's not as tight as it should be. The belt looks fine but something isn't right. I don't even know how to explain it. The timing is correct. Half way down the belt it tries to turn and flutter. I might just buy a new belt. I love My car but she is nickel and diming me to death. And thanks for your input in advance.

 

[Ghostriderdsm]

Ok let's start off with I have a 2g block with 1g head. I was gone for a month in a half and my wife and a couple of friends that have a custom shop wanted to swap out my radiator hose because it was going bad. Well someone forgot to plug the fan in and drove it about 25 miles at interstate speed and she over heated. Well when i got home and I noticed that compression was going back through the cooling system. I tore the head down and replaced the head gasket thinking it blew. Well that fixed that problem but #3 cylinder isn't firing and the compression is around 85psi. When we did the test, the compression was going through the intake. Blocked that off and it starting going through the exhaust. Also that same injector isn't working. I'm going to check the wiring and see if that's it. I'm guessing if that doesn't work then it has to be a bad injector right? And could these two problems be related? Any help is going to be greatly appreciated. Thank you.

Almost forgot. Had to buy a new timing belt tensioner. Put that on and it still seems like it's not as tight as it should be. The belt looks fine but something isn't right. I don't even know how to explain it. The timing is correct. Half way down the belt it tries to turn and flutter. I might just buy a new belt. I love My car but she is nickel and diming me to death. And thanks for your input in advance.

1- if you think you have a bad injector swap it up with another one..

Have you tryed wet testing cylinder 3? If yes then try a leak down test.

 

['97boostinGST]

If you did the compression test at RUNNING TEMP and air was escaping trough the intake mani your intake valves are more than likely fried.

 

[konvict1981]

If you did the compression test at RUNNING TEMP and air was escaping trough the intake mani your intake valves are more than likely fried.

That's what I'm leaning towards too. I didn't get a chance to look at her today. I'll most likely have her apart tomorrow. I think I might just take the whole block out and do it that way. Then when I'm done I can put her back together all nice and neat. When I bought the everything was just thrown together. Even the inter cooler is held in with zip ties.

 

[floader]

just wondering what the compression was in the other cylinders? The difference between them is really what tells the story, but 85 is damn low.

 

[konvict1981]

The compression was 150 on the rest of the cylinders. I'm going to do a wet and dry test today. I'm kind of hoping it is the valves just so I can get some titanium ones along with some beehive springs.

Did the wet and dry test today. Found that piston ring is fried. I'm going to go ahead and pull the valves tomorrow and just look them over and get some lapping compound on them and get them cleaned up. I'm going to go ahead and get a hold of advance auto's warehouse and get the bottom end kit, timing belt, maybe some motor mounts, etc, etc. Is there any thing you can think of that I should get while I'm up there?