problem with ported 5.3L DBW TB
06-01-2008, 04:18 PM
#1
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problem with ported 5.3L DBW TB
After much reading on this forum I went ahead and purchased a ported TB for my 03 DBW 5.3L
Upon starting the truck, the idle went to 2K and would not come down.
The dash display read reduced engine power.
I put my original TB on and everything was back to normal.
Is the proted TB I received not set up correctly to idle due to the larger opening.
Before I installed it, I noted the rather large gap between the plate and the inner wall but figured the computer would tell the motor to close the plate.
No such luck.
Did the place that ported the TB need to take the motor off the end and move it 1 tooth?
Any suggestions?
Upon starting the truck, the idle went to 2K and would not come down.
The dash display read reduced engine power.
I put my original TB on and everything was back to normal.
Is the proted TB I received not set up correctly to idle due to the larger opening.
Before I installed it, I noted the rather large gap between the plate and the inner wall but figured the computer would tell the motor to close the plate.
No such luck.
Did the place that ported the TB need to take the motor off the end and move it 1 tooth?
Any suggestions?
06-01-2008, 05:47 PM
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Did you shut off the engine and start it again before you swapped back to your original TB? I ported my own TB and when I started it for the first time it also idled at 2k rpms. I shut the engine off and restarted and it came back down to normal.
06-01-2008, 06:34 PM
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Stock tune
I started let ir run for 30 seconds or so, shut off, started again let run for another 3 seconds or so put in gear and then back to park, shut off, started a third time for 30 seconds or so.
Idle never went below 2K
In lookinf at the TB plate, if I attempt to close it manually with the truck off, the internal motor and such puts it right back to where is was even with no power to it.
To idle lower, it would seem that the motor needs to go lower than the natural resting position to close the throttle plate.
Do I need to reset the computer?
I started let ir run for 30 seconds or so, shut off, started again let run for another 3 seconds or so put in gear and then back to park, shut off, started a third time for 30 seconds or so.
Idle never went below 2K
In lookinf at the TB plate, if I attempt to close it manually with the truck off, the internal motor and such puts it right back to where is was even with no power to it.
To idle lower, it would seem that the motor needs to go lower than the natural resting position to close the throttle plate.
Do I need to reset the computer?
06-01-2008, 10:54 PM
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It's not supposed to shut 100%, mine doesn't anyway and i have a stock one i'm staring at and a ported one on the truck. I didn't change anything other than a tad more fuel for the ported tb on mine.
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06-02-2008, 10:30 AM
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Reduced engine power means something is wrong with the TPS sensor or it's sticking REALLY badly and not able to get the TPS feedback that it's trying for. Most likely a hosed TPS I'm afraid... Take the black cover off and check that you can manually close the blade until the half moon shaped gear contacts the throttle stop. If it does that fine, then the TPS is most likely shot.
06-02-2008, 12:52 PM
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If the throttle body has been ported incorectly and there is daylight around the edge of the blade when fully closed, the MAF test will fail because to much air gets by at closed position. Get it scanned with the TB in place if you get a chance.