Forced Induction Superchargers | Turbochargers | Intercoolers

No boost

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Old

Jun 1, 2023 | 10:42 AM

#1

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No boost

I have a 5.3 with 88mm fis turbo not building boost. I tracked issue to blow off valve opening. I have found that at idle I have about 13-14 inhg in the intake and as I open throttle vacuum is increased to 19-20 inhg which is causing blow off valve to open. Any idea as to why vacuum would be increasing

Old

Jun 1, 2023 | 10:48 AM

#2

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you arent opening the throttle enough. at wot you will see zero vacuum.

Old

Jun 1, 2023 | 11:44 AM

#3

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You dont typically want the BOV open at idle or cruise. Run a stiffer BOV spring.

Old

Jun 1, 2023 | 12:38 PM

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Black_Sunshine_99

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Stupid question, the reference line is hooked up to the lower fitting below the diaphragm, right?
If its hooked up to the dome fitting then it would open with vacuum, if its hooked to the lower than vacuum should hold it closed and pressure should open it.

Old

Jun 4, 2023 | 07:30 AM

#5

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Yes all lines are hooked up as they should be. It was a sudden change. Car was running fine and making boost and then all of a sudden it quit making boost.

Old

Jun 4, 2023 | 03:49 PM

#6

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Spring stb?

Old

Jun 4, 2023 | 04:04 PM

#7

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Hole in rubber elbows. Had it happen many times. Hard to see the hole when it's not in boost.

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Old

Jun 4, 2023 | 04:33 PM

#8

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That was my first thought only I smoked the entire cold side of they system. I have had someone tell me check the map sensor. I am running Holley terminator x

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Old

Jun 4, 2023 | 07:57 PM

#9

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I once had the rubber elbow blow off the end of one of the pipes and couldn't see it because it was in a hard to spot location.

Old

Jun 4, 2023 | 08:59 PM

#10

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Waste gate stuck open ?

Old

Jun 23, 2023 | 11:31 AM

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Is there still a turbine wheel intact?

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