I rebuilt my turbo 13b engine and installed it. Started fine and set timing with a timing light. Runs good up till the turbo starts to kick in, then it starts jumping and serging. I can go ahead and floor it and it will go but I am scared I'll blow the engine. Its a s5 engine, tranny and turbo in a s4 car. All emisions are gone. Does anybody have any ideas on what to check? Please let me know at albinores@peoplepc.com.


Thanks,
Thomas

 

possibly as simple as a boost leak. yesterday my coupling came loose at the throttlebody and had the same issue. clamp just needed to be tightened, nothign was visibly wrong.

 

Do you mean where the intercooler hose clamps are? I tryed some different things. I changed the cas, no change. I unpluged the fuel regulater, and it ran a little better. I changed the oxygen sencer and it seemed to run better. I pluged the fuel reg. back in and it still seemed to run better. The turbo would ram up smoother. The problem mite have fixed its self momentarly. It could come back. If a little air leaks around the intake where it hooks to the front of the turbo, would that cause it to buck when the turbo kicks in?

Thomas

 

yes im talking all your clamps and possibly a rip or something in a coupling or softpipe somewhere. id advise against unpluggin the fuel pressure regulator. but if that made things better, maybe double check how you ran your vac lines and make sure the fpr is working correctly.
any unmetered air coming into your motor, if you are speaking of the coupling on the compressor housing that starts the intake tract piping its unmetered (post afm), will cause the bucking, surging you described.
if it is just a boost only problem i would stop looking at things like o2 sensor and such and pressure test your piping and intercooler before spending a dime.

after you've pressure tested, if that checks out, monitor fuel pressure, boost pressure, and if you can egt's. the egt reading will tell you roughly how spot on timing is under boost which a timing light really can't do without a good load bearing dyno.

 

There is a rip in the intake tube going to the compressor but it looks like it does;ent go past the hose clamp. I mite try some silcone and tighten down it to make sure the thing is sealed. I did hook the fuel reg. back up. It does not buck like it did but I still can feel a little surging. Thanks.


THomas

 

THe o2 sensor was the problem. Runs great now.


Thomas