I've been chasing down high BLM's (148 @ hot idle) for a while. Picked up a Mighty Vac today and now need to know how & where to test for vacuum leaks. I hooked up an air compressor with a boost leak detector to the MAF hose and did not hear any leaks. How will this Mighty Vac help me out?
High BLM & Vacuum testing
- Thread starter gnx139
- Start date
Pull the vacuum lines off the vacuum block on top of the throttle body. Start pulling a suction on each line. If it doesnt hold.... go down the line at each point in that line until you find the culprit. Also check the plenum gasket and the vacuum block gasket itself. There are alot of places for a vacuum leak to occur on these cars. You need alot of patience but you will find it sooner or later.
After that has been checked the next step is maybe a leak on the intake gasket. Did you rule out fueling issues before you start on the vacuum leak hunt.
My leak causing high BLMs was the A/C control switch behind the unit in the dash. Took a while to find that one.
After that has been checked the next step is maybe a leak on the intake gasket. Did you rule out fueling issues before you start on the vacuum leak hunt.
My leak causing high BLMs was the A/C control switch behind the unit in the dash. Took a while to find that one.
vacuum 6
I have chuckers
- Joined
- Jan 6, 2006
What PCV are you running?
For the pump:
http://www.turbobuick.com/forums/general-turbo-buick-tech/310074-walbro-255l-hr-hp-fuel-pump.html
Also make sure you have 12V to the pump. You have hot wire kit?
- Joined
- May 28, 2001
Saw a post about the stem in the EGR valve being a leak source..
A "few yrs old".. Like maybe a Walbro from the famous "instant failure" time period??
A "few yrs old".. Like maybe a Walbro from the famous "instant failure" time period??
The issue about fueling is that if its too rich or lean that will affect your BLM's up or down. As far as the 3 year old Walbro is concerned...I just changed headgaskets a few months back because my 2 year old Walbro decided to crap out on me at 22 psi. From now on I will be changing mine every year whether it needs it or not. Its only $100 bucks and it will save alot of time and headache.
OK, I had some time tonight to dig around with some vacuum lines and found the top hose to be disconnected from the nipple of the vacuum canister. I'm hoping that was a big part of it. When it is not raining I'll take her out for a drive and see what's up. Most of the vacuum lines seem real brittle. I'll replace those ASAP.
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