Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Additionally I found it really helpful when I was learning how the system works to use a vacuum gauge connected at different points in the system. For instance you can remove the VSV from the system (leads to a po402 if done long-term) etc. to simplify testing by blocking the line from the EGR modulator to the intake pass-through. Add your vacuum gauge to the system after the EGR valve and you can watch when it should open. I have done this with the gauge mounted to the wiper arm so that I can watch the gauge in real time as I drive. Very informative.
Some might call this cheating, I call it effective.
@jatree
I don't recall the readings or what my guages range even is but I can say that the needle movement was clear and obvious. If it's essential I don't mind doing some tests but if you just want to figure out if the ports are clear I can recommend an easier way to do that:
-Grab a can of brake clean with a tube on the spray nozzle and a paper towel.
-Pull the rubber vac. hose off of the brass elbow for one of the vac. ports on top of the throttle body.
-With the engine running stick the brake clean tube into the brass elbow and give a little squirt. This should impact engine rpm. If it doesn't rev the engine up to 2k rpm or so and try again.
-If no rpm impact then I'd suspect a clogged port. My cleaning technique is to gently pull the elbow using pliers and a twist/pull movement then a bit of welding wire to scrub around and find the small orifice in the TB and push it clear. Keep in mind that the drilling for the elbow is way larger than the small orifice that the vacuum passes through.
-Reinstall the rubber hose on the elbow and test/clear the other port.
Also, if you just want to use your vac guage and not Brake clean comparing one port to the other should give you a sense of vac levels. Run the RPMs up and down when testing each port. One of the ports is before and the other after the TB butterfly as I recall so the vac levels really differ at idle but are closer as the throttle opens as I recall.