03Xr6T- AK New Member 8 Member For: 3y 11m 28d Posted 29/03/20 11:45 PM Share Posted 29/03/20 11:45 PM My Xr6 wont fully boost, has had new spark plugs, coils, fuel pump, fuel filter, new pod filter. Rpms get to around 3500 and starts shuddering, then comes normal. Sort of like a over boost cut. Read it could be the turbo being stuffed but otherwise any suggestions Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,240 Member For: 15y 11m 19d Gender: Male Location: Melbourne Posted 30/03/20 12:02 AM Share Posted 30/03/20 12:02 AM put a boost gauge on it to see what sort of boost it's getting to, so you can at least rule out whether it's over-boosting initially... but it seems unlikely to overboost and then the boost fall back down to an acceptable level in the higher rev ranges. pull the intake off the front of the turbo and put light pressure on the shaft of the turbo and see if the blades touch the sides or move more than a mm or so backwards/forwards. If it does, the turbo might be stuffed... otherwise you'd be looking for damaged blades for a stuffed turbo at this point. Link to comment Share on other sites More sharing options...
03Xr6T- AK New Member 8 Member For: 3y 11m 28d Posted 30/03/20 12:08 AM Author Share Posted 30/03/20 12:08 AM It'll sit around 7psi comfortably then when shuddering jumps to 12-13psi Will check for any play in turbo thank you Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,240 Member For: 15y 11m 19d Gender: Male Location: Melbourne Posted 30/03/20 12:11 AM Share Posted 30/03/20 12:11 AM 7psi is about right for a stock 03 turbo... 12-13 would indicate it's overboosting or it has been tuned/modified in the past. Link to comment Share on other sites More sharing options...
03Xr6T- AK New Member 8 Member For: 3y 11m 28d Posted 30/03/20 12:15 AM Author Share Posted 30/03/20 12:15 AM Would a fuel pressure regulator affect boost A aftermarket fpr Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,240 Member For: 15y 11m 19d Gender: Male Location: Melbourne Posted 30/03/20 12:21 AM Share Posted 30/03/20 12:21 AM no, it wouldn't cause boost issues by itself... but you wouldn't install one unless you'd modified the car for more boost via other means. Link to comment Share on other sites More sharing options...
03Xr6T- AK New Member 8 Member For: 3y 11m 28d Posted 30/03/20 12:24 AM Author Share Posted 30/03/20 12:24 AM Also has aftermarket bov, aftermarket front mount but only recently started shuddering under load. Have replaced valve springs cams and had the head reconditioned also. Car has about 265000kms Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,240 Member For: 15y 11m 19d Gender: Male Location: Melbourne Posted 30/03/20 12:36 AM Share Posted 30/03/20 12:36 AM BOV & front-mount don't significantly change airflow so it'd be fine to run stock boost through both. what changed, if anything, between when it was running OK and when it started shuddering? Link to comment Share on other sites More sharing options...
03Xr6T- AK New Member 8 Member For: 3y 11m 28d Posted 30/03/20 12:38 AM Author Share Posted 30/03/20 12:38 AM Before all these were done to the car other than the blow off valve. The blow off valve was the first thing and car was working fine. Then suddenly started shuddering under load. Iv done all that to the car since to try figure it out. It's still not running as good as it use too especially with the shuddering Let me fix that, I mean the shuddering has stopped a little but still not reaching full capacity Link to comment Share on other sites More sharing options...
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