Underhood sound

joe s · Post by **joe s** » April 13th, 2006, 7:42 am

Hello. I have a little problem with my '98 R and would like to ask for advise. Recently got the 90K service ie timing belt (which by the way looked so good the mechanic could not believe was original, - go Honda), etc. A week or so later I began hearing a high pitched whistle/tone under the hood which only showed up at idle. It would go away with even the slightest throttle input, no change with clutch, brake. Mechanic thought it was the alternator - diagnosed after locating the sound and removing the alternator belt and the sound stopped, and recurred after putting it back on. I picked the car up and after driving it for a few moments, letting it warm up and therefore idling at normal idle rpm, the whistle was still there!! - mechanic said it must have been a faulty alternator (OEM) and replaced it. It seemed to take care of the problem. However, now, a week later, I'm hearing the damn sound again! Seems awfully coincidental that 2 alternators would be bad - what do you all think?? Thanks for your help!!
Joe

Bbasso · Post by **Bbasso** » April 13th, 2006, 1:04 pm

could be the Alt, is the belt properly tensioned?
Where did you get eh Alt from, maybe it's a crappy rebuild- Try a OEM part if it's not.

BudMan · Post by **BudMan** » April 13th, 2006, 3:12 pm

Although it may not be the case this time, remember some intakes like AEM really like to whistle at certain constant rpms - slightest change & no whistle.

captainzorg · Post by **captainzorg** » April 13th, 2006, 7:12 pm

My AEM CAI whistles like a bastard!

joe s · Post by **joe s** » April 14th, 2006, 11:55 am

Thanks for any suggestions. The car's pretty much stock (everything except a K&N air filter), so hopefully it's the belt tension. Will keep you utd
Joe

joe s · Post by **joe s** » April 22nd, 2006, 12:02 am

Hmmm, still a problem. Alternator (OEM) replaced, still the whistle sound while in idle, going away even with the slightest increase of rpm. Vacuum checked, no leaks. Alternator belt changed, PVC valve changed, vacuum/tension(?) valve changed (forget what this was, so sorry for the wrong nomenclature).......STILL the idle whistle/sound remains. Mechanic cannot find it.
I talked to an Acura mechanic; he'll look at it whenever I can get it in. Any thoughts?

joe s · Post by **joe s** » May 3rd, 2006, 10:41 am

OK, thought I'd keep you utd - I know you're on the edge of your seats(!!). Acura mechanic, seemingly a very bright guy - put another oem alternator on it, since the sound went away upon removal of alt. belt. The sound remains; takes a few moments before returning (pressure buildup?) and no obvious relationship to anything else but throttle (any rpm >900 or so and the sound goes away). Seems like the idle is now a little higher than normal ie approx 1000 even after a 50 minute drive or so. Otherwise car is running great.
Mechanic's thought about the relationship to the alternator belt is that the computer compensates a tiny bit for load changes ie with/without alternator hooked up, thus the lack of sound at idle WITH alternator belt taken off. He's going to call some regional people today for help - apparently is stuck just like the previous mechanic.
Hmmmm, why me..........oh well, it's a mechanical problem of some sorts and therefore will sooner or later be diagnosed and fixed; that's my hope anyway