Testing vacuum on MPS?, Is it as simple as hooking up a mityvac? |
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Testing vacuum on MPS?, Is it as simple as hooking up a mityvac? |
burlybryan |
Apr 13 2021, 07:53 AM
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#1
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Member Group: Members Posts: 106 Joined: 25-May 20 From: Saint Paul Member No.: 24,311 Region Association: None |
Does it need to be energized to test vacuum or can I just bench test it with vac hose (properly clamped) and a mityvac? I have a few on hand and while all test correctly for resistance on the appropriate pins, I'm not able to get any vac with my mityvac. Am I missing something or are the diaphragms all toast?
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914werke |
Apr 13 2021, 07:57 AM
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#2
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"I got blisters on me fingers" Group: Members Posts: 10,142 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
if you can apply say 5 or so #'s of vacuum on the port & it doesnt hold (at all or drops to 0 in a period of time) its toast.
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brant |
Apr 13 2021, 08:05 AM
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#3
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914 Wizard Group: Members Posts: 11,640 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
its that simple... if your mighty vac is working correctly... they must be all toast
I believe Paul Anders said 15Hg of vacuum? but would have to go check to be sure brant |
BeatNavy |
Apr 13 2021, 08:22 AM
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#4
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
its that simple... if your mighty vac is working correctly... they must be all toast I believe Paul Anders said 15Hg of vacuum? but would have to go check to be sure brant Yes, 15 in Hg is the standard test, simulating idle vacuum on a stock engine. I've read a couple of specs about how much it can leak (e.g., < 5 in Hg in a minute, or < 5 in in FIVE minutes), but if it won't hold any vacuum it's done. http://www.tangerineracing.com/mpsdiaphragm.htm Here's Brad's page: https://members.rennlist.com/pbanders/manif...S%20Diagnostics |
bob164 |
Apr 13 2021, 08:43 AM
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#5
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Member Group: Members Posts: 96 Joined: 10-February 18 From: SoCal Member No.: 21,877 Region Association: Southern California |
Double check you gauge and connections to make sure these are valid readings. Pull a vacuum on a vacuum cap first then work up from there.
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914werke |
Apr 13 2021, 08:50 AM
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#6
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"I got blisters on me fingers" Group: Members Posts: 10,142 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
15Hg=7psi approx
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burlybryan |
Apr 13 2021, 09:14 AM
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#7
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Member Group: Members Posts: 106 Joined: 25-May 20 From: Saint Paul Member No.: 24,311 Region Association: None |
Got it. That's what I thought. I can pull vac with the mityvac on my skin, so I think it's fine.
Thanks. |
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