Haunted speedometer (yet another weird Ranger issue)

[K Thompson]

Hey Guys
I have a 2003 Ranger 3.0l 5 speed. Bought it a year ago with 152k on the clock, and now has 163k.

Here is the issue. Last month I started hearing a chirping / buzzing noise that would change pitch with change of engine rpm. I thought it might be a cam position sensor, so I replaced it. Not where my noise was coming from. BTW this noise can only be heard in the cab with the windows up.

About 5 or 6 months ago the speedometer (electrical not mechanical) started jumping erratically between 0 and 30 mph. This morning I noticed the chirping noise coming and going was coinciding with the change of pitch or buzz.

Until this happened I was going to look at the bearings in the alternator, but now wondering if it is brushes or brush rack.

Would appreciate all your comments!!!

Thanks in advance
Keith (The Boltman)

 

[K Thompson]

Problem solved (but do not understand why)

I had an IAC valve ordered that came in today. 5 minutes after installing it, I went for a test drive. Now besides it not over revving, the buzzing is gone and the speedometer is working correctly.

I can understand the buzzing sound because there is air involved, but do not understand the speedo now working correctly.

Being an old fart, I will take the wins when I can get them!!