Engine only pulls 3" hg of vacuum at idle?
- Thread starter ram360
- Start date
TheUser said:maybe you have a gunked up/stopped up hose some where - maybe even the one you're testing
I check all of them for cracks blockages and everything. The line I was testing was directly off the vacuum tree on the firewall. I have brand new hose only like a 3" piece of it going direcly to the gauge.
RsStanG1987 said:
I have a bottle sitting on the car. But don't have enough vacuum to put it in.
Having a vac on the crankcase is where I would focus. Well first I should ask how you checked this. When I checked my crankcase for pressure/vac, I plugged the TB/VC hose and removed and capped the hose from the pcv to upper intake. Then I was able to put the gauge on the pcv for an accurate reading. I will assume you did this, or something comparable.
If you do have a vac, even just slightly, that would suggest a leak between the intake and crankcase. I did have this happen to me a short time ago. When I had installed the lower intake the gasket had slipped down about .25" Can you visually verify that the gasket did not shift during installation?
Hope you get this sorted out soon
jason
If you do have a vac, even just slightly, that would suggest a leak between the intake and crankcase. I did have this happen to me a short time ago. When I had installed the lower intake the gasket had slipped down about .25" Can you visually verify that the gasket did not shift during installation?
Hope you get this sorted out soon
jason
While having a gauge hooked up to a central line, one can also pinch off ancillary hoses, one at a time, till vac goes back up. Then trace that pinched hose further downstream.
With that huge a leak, Jason's advice is the route I would follow though.
Good luck.
With that huge a leak, Jason's advice is the route I would follow though.
Good luck.
I messed around with it some more today. Idle is now at ~5" hg at 2000 rpm I have ~10-11" hg. At 3500rpm it peaks at ~15" hg and then drops off after that. Not really sure how normal those number sound but at least that's where I'm standing right now. None of the accessories that use a vacuum source are leaking. I've isolated each one sepeartly and then all of them together w/o any change in the amount of vacuum.
vristang said:
I did exacly as you suggested with pulling the vacuum from the PCV. It hardly moves the needle. maybe ~1 or 2" hg reguardless of rpm. I tried it last night and again today just to double check. I will go and check the intake gasket and see if I can notice anything with the gasket. So does it sound like a crankcase vacuum problem to you guys since the other stuff has checked out ok? I really appreciate the help so far everyone.
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