how to check for vaccum leaks on Gen 1 L

9

94silver

Restoring a 94 :)
I rebuilt my 351 and Trans and now have high idle 1000-1400 rpm. I have read many posts here and replaced the IAC and TPS. I performed the diconnect IAC valve and truck runs the same no change(sounds like a vac leak) The only thing i did different from before rebuild was i removed the AIR PUMP and capped the vac lines going to the old equip.

Any ideas? i have not check codes since a VAC leak is my issue,

Thanks in advanced guys :)
 
Tried and true method is a can of brake kleen. But I would first verify that there is voltage at the iac.
 
Thanks MJ351 thats something i will get to tomorrow. How do i use the brake kleen? spray around the intake?
 
94silver said:
Thanks MJ351 thats something i will get to tomorrow. How do i use the brake kleen? spray around the intake?
Click to expand...

Affirmative, just concentrate on known areas Vacuum line connections gasket mating surfaces.. Did you disconnect the brake booster and see if your leak decreases?
Also, did you replace your injector seals? if one of them is leaking it will produce a nasty leak...
 
Seals yes. I haven't tried the booster hose. I will do it tomorrow after work. what do i look for? pull it and cap it? if idle decreases the the booster is leaking? Also what will i see when i spray brake keen? bubbles or what? I will check in the morning for your answers, Thanks a lot MJ!
 
Pull booster hose at check valve and plug / cover with thumb. If you see a drop then its in the booster. When using brake kleen, if you encounter a leak the rpm will change when sprayed on a leak....
 
Ok i will do that Today! :tu

---------- Post added 05-29-2012 at 06:57 PM ----------

Well i did the brakekleen thing and found no leaks or change in RPM. I pulled the booster hose at the intake TB and the engine almost died.When i plugged the inlet where the hose connects it came back to high idle 1100 rpm or so.

---------- Post added 05-29-2012 at 09:52 PM ----------

MJ found it!!! it was an open hose on the intake:grin1: i plugged it and it idle around 700 rpm.. the booster checked good.

Thanks for the help MJ :tu
 
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