MED wrote:
Over the past couple of weeks, I've noticed a strange pulsing noise. It appears to be coming from the intake hose intercooler area; the noise isn't there when I first start it up only when it is idling after driving for awhile. The noise just sounds like air pulsing; If I squeeze the intake side tube; the pitch of the noise changes and pretty much goes away.
Other info:
1. My OBD2 blue tooth is broken so I haven't scanned it...will order a new one soon.
2. I have the the MAF disconnected and has been disconnected for very long time.
3. I have the FCV disconnected and it was disconnected for a year because the FCV failed with codes.
4. Noise did not happen with a change in performance.
5. I do not have an oil catch can or mod so oil has been running through the intake. (dumb I know...just never got around to it)
6. Jeep has almost 230,000 miles.
7. Intake hoses are in good condition
8. The last time I checked boost pressure about 4 months ago; all seemed good, but the turbo has 230,000 miles and I am not sure the cat is in very good condition either.
9. I just drove it on a long trip through the mountains last weekend and I got almost 28mpg so the fuel economy is still good.
Remove the turbo inlet hose and check for tears.
Stick your fingers into the turbo and try to wiggle the shaft. See if it spins freely.
Also check for codes when you get a chance.
If the turbo is infact doing some sort of engine braking, that would indicate a problen with the vanes, turbo vacuum actuator, or vacuum solenoids.