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PCV replacement?

Williebeaman

Williebeaman

1/2 ton status
Joined
Jan 4, 2019
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Location
Austin tx
Hey guys I got a 89 jimmy 350 tbi, I’ve been trying to find the source of my occasionally stalling out at red lights idling or when I put it in reverse and this is next on my list. Does it just pull right out of the valve cover? Is it as simple and popping old one out and popping new one right in place no tools or sealant necessary?
 
Yes,its just a friction fit in the valve cover grommet..
Check the hose that goes from it to the intake vacuum source,it may be plugging up with carbon or sludge,and if it has any cracks it will let air get in and dilute the fuel mixture--also if it is too soft,it can collapse under vacuum,its supposed to have hose stiff & thick enough not to collapse..the PCV valve is a controlled vacuum leak so its critical to get the correct one and ensure its getting full vacuum.

It could be you have a vacuum leak elsewhere as well,you can spray carb cleaner around the base of the throttle body,intake gaskets,other hoses,to see if the idle speed changes ,that will indicate air is sneaking past gaskets or maybe a vacuum hose to the brake booster or other item has a bad spot or crack..the booster itself can leak vacuum too,when you apply the brakes,usually though you'll notice a harder pedal,as it reduces the amount of power assist..

If the EGR valve isn't fully closing at idle that too makes the same symptoms as a vacuum leak,only your getting exhaust fumes instead of fresh air diluting the fuel/air mixture..one chunk of carbon can cause it to stay open a little..
 
Thanks for the reply, yea I am having a leak at the base of the throttle body as well. I’m having problems finding the elbow fittings that go onto it at auto stores though. They all have plenty of hose but not the right angled fittings that connect to the throttle body of that makes sense?
 
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The first picture I’m pointing at the elbow fittings I’m talking about the second picture I’m just curious what it is? I’m pretty new to working on my own vehicles so I’m still trying to learn
 
I do not run an elbow fitting on my TBI. I run the crank case vent tube straight into the TBI. The vacuum leak at the base of your TBI could be a worn out throttle shaft. There is a guy that has a company called Vic Morse that can do a good job of rebuilding your TBI. He will re-bushing the throttle shaft as well.
 
I just rebuilt the tbi about two weeks ago. The throttle shaft seemed to be nice and tight no slip or anything. I even feel like my truck was performing a little better after but still have the stalling issue. I sprayed some starter fluid at the base and it for sure revs up. I really think I just need to replace all my vacuum lines and fittings they are all super old dry looking and some cracking. I just can’t find the dang fittings
 
Williebeaman said:
I just rebuilt the tbi about two weeks ago. The throttle shaft seemed to be nice and tight no slip or anything. I even feel like my truck was performing a little better after but still have the stalling issue. I sprayed some starter fluid at the base and it for sure revs up. I really think I just need to replace all my vacuum lines and fittings they are all super old dry looking and some cracking. I just can’t find the dang fittings
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You might also have a bad base gasket or a loose bolt which causes the leak at the base
 
The other thing i learned was that different engines use different PCV valves-----v-6, small block, big block all different valves for different air/vacuum differences. So, be careful of that as well.

Don't have time to provide part numbers now. Maybe next weekend.
 
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