Help with vacuum gauge readings. Extremely low. Possible leak?

Kylebach14

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Just finished up a HCI swap and noticed that it has no power so I did a vacuum test and it flickers between 7 and 10 which is extremely low. I heard that if you have a cam it will flicker. I just want to know why it flickers and why its so low. When I accelerate it climbs up and gets more steady. I've sprayed all over and cant find a vac leak. I'm thinking it could possibly be a lower intake leak. Would it be a waste of time to re do my lower intake gasket? Thanks

Heres a vid of the gauge:
https://www.youtube.com/watch?v=NbfrovhFpQ0
 

rz5.0

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Cam? Is your timing ok. How is the fuel pressure. . Use some permatex tack gasket sealer

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Kylebach14

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TFS 1 Camand timing is set at 10 degrees with spout out. The engine was cold when I tested it if that has anything to do with it
 

rz5.0

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th


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rz5.0

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Tfs1 I want to say I had 17 inches vacuum. When I did mine I unplugged every vac line plugged them. then plugged in one at a time. . It can also be the tune. Injectors size?

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Kylebach14

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Stock 19 pound injectors,TB, MAF.
I heard it may be a possible valve seal issue but I dont think thats the issue. I'm hoping its just the lower intake
 

rz5.0

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It's possible or a simple vac leak. Did you check the hoses going to the evap. Smog & egr hard plastic lines

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Kylebach14

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I deleted the smog and taped off the smog lines. I also deleted my AC and left the two pipes in the firewall open. would this affect anything?
 

toyman

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There are a lot of hidden vacuum lines. You could pay to have a smoke test done or you could fab a fitting to attach to the TB with a tire valve that will allow you to pressurize the system using a bicycle pump. If there isn't a leak the pressure will hold and if it's leaking you should be able to hear the hiss of the escaping air.
 

Kylebach14

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I'm not sure what is going on. I cant find a leak at all on this, yet it has low vacuum. Someone on another forum said maybe my rockers are too tight.
 

rz5.0

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It's possible if your rockets are to tight then your valves are not closing all the way. . Also is your car tune?..

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Kylebach14

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No it doesnt have a tune. I'm going back in and re doing my rockers. I think I may have tightened them too much on the preload.
 

Kylebach14

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Re-did my rockers and it only gave me about a 1 or 2 inch improvement of vacuum. I found a leaky injector spewing gas out the top where it meets the fuel rail. Could this be a possible spot where I'm losing vacuum?
 

toyman

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Leaking injector doesn't affect vacuum. That's likely a bad O ring. Check this site. You appear to be describing scenario 10 on the list. If it's late valve timing then you have your work cut out for you. Guessing the cam was not positioned correctly. Can you confirm the crankshaft and cam shaft sprockets were aligned and that the timing chain deflection was within spec.
 

Kylebach14

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When i installed my timing chain, I put it in dot to dot. Scenario 10 also says that it could be a possible intake leak? I deleted my ac and wasnt sure if anything from there would cause low vacuum. I plugged the plastic line by the passenger side fenderwell but I'm not sure if there is anything else?
 

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