Bingo!! 
No vacuum, help please!
Thread Starter
Launching!
Joined: Jul 2012
Posts: 207
Likes: 8
From: Spokane, WA
No vacuum, help please! I got my L92 Swap running. It seems to drive and shift well too! I do have something a bit interesting happening though. I am running the stock truck intake manifold, that has an evap line, that should be vacuum, as well as the rear brake booster port that should be vacuum. Neither of these seem to be have any vacuum at idle. I noticed because my brake pedal is much stiffer than it should be. I have all other PCV routing how it is in a stock location, and the passenger side valve cover vent routed to the intake between the MAF and TB. Passenger vent is routed to top of intake position like stock. Besides no vacuum, it seems to run and idle well (although, when I stab the throttle, it doesn't immediately return to idle, but hangs high and comes down slowly. Not sure if that is normal or not.) Anyone have any thoughts on this?
-Nick
-Nick
Last edited by nicke; May 5, 2014 at 10:09 PM.
TECH Resident
Joined: Mar 2012
Posts: 821
Likes: 4
From: Elkridge MD
Not sure about the vacuum, but on my 5.3 I was having an issue like that with the idle acting funny after revving. I took out the sensor on the side of the TB (I think it's officially called an AIC or IAC (Idle Air Control or something) Mine was on the driver's side....not sure if you have yours there or not. It LOOKS like you have nothing plugged into that port in the TB, but my 5.3 TB looked quite different.
If that plug is missing or just not plugged in, it could explain your vacuum leak too, I imagine.
Just guesses though...I am no expert.
If that plug is missing or just not plugged in, it could explain your vacuum leak too, I imagine.
Just guesses though...I am no expert.
Thread Starter
Launching!
Joined: Jul 2012
Posts: 207
Likes: 8
From: Spokane, WA
Not sure about the vacuum, but on my 5.3 I was having an issue like that with the idle acting funny after revving. I took out the sensor on the side of the TB (I think it's officially called an AIC or IAC (Idle Air Control or something) Mine was on the driver's side....not sure if you have yours there or not. It LOOKS like you have nothing plugged into that port in the TB, but my 5.3 TB looked quite different.
If that plug is missing or just not plugged in, it could explain your vacuum leak too, I imagine.
Just guesses though...I am no expert.
If that plug is missing or just not plugged in, it could explain your vacuum leak too, I imagine.
Just guesses though...I am no expert.
-Nick
Thread Starter
Launching!
Joined: Jul 2012
Posts: 207
Likes: 8
From: Spokane, WA
Trending Topics
The white plastic thing that the hose is hooked to on the booster. The hose should be on the other side of it, and the part in the booster should have the hose hooked to it.
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Verdad Gallardo Thread Starter
Launching!
Joined: Jul 2012
Posts: 207
Likes: 8
From: Spokane, WA
That wouldn't explain the no vacuum from the evap line though would it?
-Nick
Thread Starter
Launching!
Joined: Jul 2012
Posts: 207
Likes: 8
From: Spokane, WA
After switching that around, I have vacuum assisted brakes again!!! Thank you!
Can anyone tell me why the evap isn't drawing vacuum? It's the port on the front top of the intake, then comes down the drives side to some type if solenoid, then out to my vacuum gauge. Why would there be no vacuum here?
Thanks
-Nick
Thread Starter
Launching!
Joined: Jul 2012
Posts: 207
Likes: 8
From: Spokane, WA
That makes sense. I'm guessing since I had the evap stuff taken out of the tune, and my harness doesn't even have that connector, it is probably shut off for good.
I'm guessing if I hook into it upstream from that solenoid, I should be able to show vacuum all the time though right?
Thanks for all your help!
-Nick
I'm guessing if I hook into it upstream from that solenoid, I should be able to show vacuum all the time though right?
Thanks for all your help!
-Nick
