1995 T-Bird 4.6L, no power, popping and hesitating

[tcarle]

I broke a valve recently (after trying to figure out why the engine was hesitating and engine codes kept pointing to a EGR/EGP problem). I had the heads rebuilt, reringed the block and put everything back together. Just had thge Mass Air Flow sensor replaced. Since putting the car bac together, I have developed a popping (backfiring) during attempted acceleration. All cylinders at 125 psi compression. New plugs and wires. The popping seems to get better after the enginer is warm, but still has no power and cannot get out of it's own way. No engine codes.

PLEASE HELP....I MISS DRIVING THIS CAR!

[97Bird]

Check to make sure you put the plug wires back on in the correct order! Did you make sure the cams were lined up properly when you installed the timing chains? You get a backfire when the plug is firing at the wrong time or a valve is open at the wrong time. A valve might not be closing all the way. Just a few things to check.

[tcarle]

I double checked the wires and all was good. After bending all of the valves int he left bank, (I had the timing chains adjusted way wrong), I had that head redone and set both cams correctly. I would think if the cams were wrong, I would get considerably more backfiring (I really don't want to take the front of the engine apart again).

Is 125 psi compression indicative that the cam adjustments should be OK with a new valve job and rings? If I should be seeing higher compression, I will take it down again abd recheck the adjustment.

Thanks tons...Any other ideas are greatly appreciated!

[97Bird]

Did you check the ignition timing yet? My book for 97 gives a range from134psi to 250psi for compression range. The lowest reading cylinder of your engine should be no less then 75% of your highest reading cylinder. Have you done a vacuum test yet to see if any valves are sticking? Check your plug wires again! It's easy to get them mixed up where they go across the front of the engine from one side to the other.

[thunderbird muscle]

yes Check the plug wires! They are easy to get messed up.

[97Bird]

I just reread your first post and noticed that you installed new rings. Your compression will be lower then normal until the engine has been run long enough to break in the rings. If all cylinders are within 25% of each other then don't worry about the low reading. (125psi) After just removing the front cover on my 95 Bird to replace freeze plugs I can understand why you don't want to go through that hassle again!

[vasta41]

i have the exact same problem (with the popping and backfiring) the only difference being mine was a progressive problem, and it seemed to get worse with things like a new exhast (i have a 95 V8 with to CATs up front near the manifold and i just have two pipes going to two flowmasters) and before this was a serious problem, i put in a custom air intake, but it was soon taken out after it made the problem worse. since my problem was progressive, what should i do?