I have been boosted for some time now, however for the first time on a car with a MAF Sensor. So, recently I began noticing that when I come to a stop, my car dies. I assumed that it does this since their may be a slight vacuum leak, and at idle minimal fuel is input, the car often dies (running a bit on the leaner side on the tune at idle). Another thread exists regarding this situation (https://www.scionlife.com/forums/showthread.php?t=166972), however has had no luck just yet as well.

I could hear a leak, so after careful inspection and some carb cleaner, was able to determine it was coming from the second runner of the intake manifold. I took the manifold off and replaced the gasket which had been slightly deformed near runner two. After reinstall, the issue was still present. All lines were checked, and rechecked therefore I assume the plastic manifold may have developed a crack.

I replaced the manifold, re- installed, and checked every line, and now the car will not start properly, is misfiring, and the leak seams even louder. It is throwing all the codes I would get for a vacuum leak but I cannot find any issues in the lines. The manifold is properly attached to the head, and the gasket has made the seal. The lines on the manifold (brake booster, pcv) as well as the throttle body (intake, evap) are all secure with no leaks. The manifold was bought used, and I assume that it may be cracked. I checked the head and it is not warped. Anyone have any suggestions? Any lines I am missing? Anything that normally goes sour? This is a pain in the ___ to put on a new intake manifold and then reinstall everything just to see if it even works.



Please HELP ME

 

there is one vac line running from the back of the crankcase to the intake manifold, this needs to be on. that is the only vac line on the actual mani itself. do another carb check to see where it is leaking at now

 

Sounds like you got a worse intake manifold. check the edges along the intake manifold to see if there are leaks where it should be sealed.

Its a painful car to work on somtimes for sure.

 

i kinda was having the same problem?? car will start fine and drive but when i press the brake down the car leans out really bad!!! it was pushing air back into the intake manifold!! long story short we came to a conclusion that the diafram inside the brake booster had to of gone bad and now i need a new brake booster!! dont know if this helps you but i was just relaying the issues that im going thrue.....

 

Yes, I made sure that the pcv hose was connected. I also checked the edges around the manifolds and conducted a leak test, with no leak. I know for sure their is a leak, I just cannot find it within any of my lines. Next assumption may be throttle body related or brake boost related. Thanks for all the feedback, more will also be greatly appreciated!

 

Will the car idle if you are just sitting there? If so get some intake cleaner, or throttle body cleaner spray and start spraying around the intake manifold if the idle changes then you know where your leak is.

 

thats what he did in his first post man.

 

Found the issue!!! A rubber grommet from injector #2 was cracked. The crack caused the grommet to tear apart. When I replaced the manifold, only a piece of the grommet was their so it began leaking terribly without any fuel leakage. Upon inspecting, I replaced, installed, and now its beautiful. Thanks for everyones help!!!

 

good stuff. congrats on figuring it out.