2G car idles, but bogs past 2500 rpms

[edmaxx]

i recently rebuilt a 4g63t, had to use a cas sensor to get it to run, had it running great for about 10 min, then i noticed there was a 100a alternator/ choke fule spot. i threw one in and the engine made some crazy noises and stalled. now it idles poorly and will not rev above 2500-3000 rpms without bogging out and blowing out alot white of smoke. i checked my timing and noticed it slipped 7 cogs on the crank but not the cams. i reset it, and the exhaust cam kept trying to move on me and i couldnt get it timed right for the longest time. this is running me up the wall, please help. car runs but will not rev up.

....

 

[hubbazoot]

If you've done a boost leak test, ignore this next paragraph.

I had an FMIC assembly done by some noob previous owner on my car when I bought it and was all to familiar with boost leaks by the time I got the custom pipe welded. Make sure that you don't have a boost leak somewhere and that your maf is on right.

Otherwise, it sounds like something inside the engine bent/broke...perhaps a valve?

 

[evil tsi]

i second the boost leak test, had the same problem not being able to rev past 2500-3000. it ended up being a silicone coupler blowing off.

 

[Tyeler18]

Since this all started when you jumped time I'd say you more than likely have bent valves or it's still out of time. Make sure all your timing marks are all lined up still. Then boost leak test, if both of those check out do a compression test.

 

[mcewendj]

The 4G63T is an interference motor. This means that if the engine is out of time at all it is very possible that the valves have come into contact with one or more of the pistons. The easiest way to find out if you have a bent/broken valve is to remove the front cover of the motor. Time the engine and make sure it is dead on turn the engine two or three complete revolutions with a breaker bar and double check your marks. If your marks are still lined up remove the spark plugs and check compression on all 4 cylinders. you should see compression numbers around 150-170 psi if you have one cylinder (or more) that is obviously low you have engine problems

 

[hubbazoot]

The 4G63T is an interference motor. This means that if the engine is out of time at all it is very possible that the valves have come into contact with one or more of the pistons. The easiest way to find out if you have a bent/broken valve is to remove the front cover of the motor. Time the engine and make sure it is dead on turn the engine two or three complete revolutions with a breaker bar and double check your marks. If your marks are still lined up remove the spark plugs and check compression on all 4 cylinders. you should see compression numbers around 150-170 psi if you have one cylinder (or more) that is obviously low you have engine problems

If it's a 1g, 7.8:1 compression could be around 115 psi. If they're not even across all four, you have a problem.