unusual noise (not ticking) '91 2.6l
 

I just got a 1991 TrooperII 2.6/5spd 130kmi (6mo. on rebuild)

There is a noise under the hood that I is NOT the ticking noise everyone talks about.


I used a stethescope and determined that the noise is in the Smog Pump system. I havent had a car w/ an air pump in over 10 years, so I am not too experienced with them.


The sound is loud enough to hear me coming down the street. Its almost a chirping sound. Similar to what an older VW Bug might sound like, or an exhaust leak.

The noise is not heard @ idle, and while revving in neutral the sound can only be heard a few times. It is most noticeable while driving, during acceration, in any gear.


Is this a sign of a bad pump? I cant imagine the engine is supposed to sound this way, any suggestions?

my trooper started off making a chirping sound right before my alternator belt weakened so bad, which lead to the squealing noise. may not be it but at least it wouldn't hurt to see :)

I checked all of the belts, they are in good shape.

I also tried running the engine with the Air pump belt removed and then the PS belt off to see if either of those were causing the noise.

So far, nothing. I have been trying to find another Trooper like mine to hear it run and see if its mine or if its just supposed to sound that way.