i really need some help. engine issue

[thisxdayxfwd2]

my top end was rebuilt and was running fine. i just added a fmic, 3" exhaust with no cat, a 16g, a 2g manifold and now im having issues. it starts fine and idles fine but was you put any throttle to it, it sounds like a bunch of marbles in the motor. It had old gas so I replaced it and put 91 octane in and some booster, and i changed out the plugs but its still doing it. I have the feeling its spark knock but im not sure. could it be that the timing is off????

 

[knochgoon24]

Are you sure something didn't get into the motor? Pull the plugs and look into the cylinders with a flashlight. Also, try using one of the telescoping magnet things to fish around inside to check for chunks of debris.

It could also be from the turbo. Check for shaft play.

 

[tkelly27]

If I were you I would not drive it until I had checked everything out. Chances are good it may not be something bad, but if it is, you'll only be making it worse and increasing the potential for it to damage something else. Start from the outside in. Check everything that moves on the engine that you can easily see including turbo, accessory belts, pulleys, water pump, and harmonic balancer. Then start to think about things under the timing belt, and inside the engine. A stethoscope can really help you out.

If you have a separated crank pulley you can ruin your timing belt, if you have a spun rod bearing or something else in your short block wrong you could be damaging your cylinder walls. Most of the other things it could be don't have huge consequences, but it's not worth finding out the expensive way.

 

[thisxdayxfwd2]

hmmm.. the turbo is brand new but i will check for play, i took the plugs out earlier and it looked fine. i also replaced the valve cover and the cams were fine. i just dont understand why it would be fine at idle but not with any load. i know my knock sensor isnt in very good shape could that be a possibility?? if there was something that some how got into the motor wouldnt it do it at idle too??? could the timing be a possibility, or not getting enough fuel?? oh and its a project car so i havent driven it at all. im just scared to even start it up!!!

 

[tkelly27]

Our volvo sounds like marbles when you give it a rev. It's the power steering pump pulley/bearing.

It could be anything that moves in your engine. Does it happen at a certain RPM?

I don't think it would be a fuel or a knock sensor issue. The knock sensor is like a microphone, and I've never heard of anything detonating that badly while not under load.

 

[Butterfinger]

I think your on the right track sounds like spark knock may try higher octane and check that timing with a light.

 

[ElectricBlueTSi]

Did you remove a secondary 02 sensor?