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I have two issues that may be vacuum related. I have never gone after diagnosing vacuum issues before. I will outline the issues and questions are at the bottom:
First I do have an idle which fluctuates after a few minutes of driving from a cold start up. No issues on cold engine. The idle seems to get down to 550 and then go to 850. This occurs where or not the Ac is on or off. If in park or neutral, it seems to be normal and not fluctuate. When I do shut the Ac off though, it jumps to 1200 to 1400 and the fall back to 600 and then fluctuate if it had been prior. With this I do have the common air intake whine or humming noise.
Periodically at some stops, it idles normally at around 600-700.
So far I have quickly done the starter fluid spray test on a cold engine and found change in idle. I cleaned the air intake tubes, new motorcraft air filter, cleaned maf, throttle plate, cleaned iac but reused gasket. Looked over vacuum like the best I could. Found good build up on line from throttle body to vapor purge valve.... The build up was lots of dust maybe, but it was directly behind the egr. When I took line off, I noticed a tear at the Vpv connector... Trimmed it off and tube seems ok. After all this, I disconnected positive battery cable to reset ecm. It is still occurring but does seem the air intake whine is not as loud as before, but still present.
Next is the common, panel selection on the EATC blows out the defrost vents most of the time as defrost vents are the default. Sometimes the panels produce output, usually when slowing down and rpm drops below 1000 during a stop. Then on acceleration, it returns back to vent from defrost.
Looked over just a few lines that are easy to look at but nothing obvious.
So a few questions, from a newbie:
Are these two vacuum systems mutually dependent on each other?
Is there a good set of tests on the EATC vents to narrow down which vacuum lines and valves to look at?
Does it make sense to go after one before the other or start with panel vacuum?
Can someone point me to good diagrams for the entire vacuum system? Maybe detailing where some of these components look like or are located?
Thanks in advance !
First I do have an idle which fluctuates after a few minutes of driving from a cold start up. No issues on cold engine. The idle seems to get down to 550 and then go to 850. This occurs where or not the Ac is on or off. If in park or neutral, it seems to be normal and not fluctuate. When I do shut the Ac off though, it jumps to 1200 to 1400 and the fall back to 600 and then fluctuate if it had been prior. With this I do have the common air intake whine or humming noise.
Periodically at some stops, it idles normally at around 600-700.
So far I have quickly done the starter fluid spray test on a cold engine and found change in idle. I cleaned the air intake tubes, new motorcraft air filter, cleaned maf, throttle plate, cleaned iac but reused gasket. Looked over vacuum like the best I could. Found good build up on line from throttle body to vapor purge valve.... The build up was lots of dust maybe, but it was directly behind the egr. When I took line off, I noticed a tear at the Vpv connector... Trimmed it off and tube seems ok. After all this, I disconnected positive battery cable to reset ecm. It is still occurring but does seem the air intake whine is not as loud as before, but still present.
Next is the common, panel selection on the EATC blows out the defrost vents most of the time as defrost vents are the default. Sometimes the panels produce output, usually when slowing down and rpm drops below 1000 during a stop. Then on acceleration, it returns back to vent from defrost.
Looked over just a few lines that are easy to look at but nothing obvious.
So a few questions, from a newbie:
Are these two vacuum systems mutually dependent on each other?
Is there a good set of tests on the EATC vents to narrow down which vacuum lines and valves to look at?
Does it make sense to go after one before the other or start with panel vacuum?
Can someone point me to good diagrams for the entire vacuum system? Maybe detailing where some of these components look like or are located?
Thanks in advance !
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