Injector pulse?

[stewy]

Prior to a 3000 mile trip I took my '01 outback to the nearest Subie dealer
who happens to be 140 miles from home.

They gave the engine, 2.5 with 65K miles, a clean bill of health. I
mentioned a tapping noise on cold start even in hot weather. The service
writer asked whether it disappeared after warm-up, I confirmed that it did.

He called it "fuel injector pulse" and not to worry.

I'm a noobie on this group. I would appreciate your thoughts.

 

[Carl 1 Lucky Texan]

Prior to a 3000 mile trip I took my '01 outback to the nearest Subie dealer
who happens to be 140 miles from home.

They gave the engine, 2.5 with 65K miles, a clean bill of health. I
mentioned a tapping noise on cold start even in hot weather. The service
writer asked whether it disappeared after warm-up, I confirmed that it did.

He called it "fuel injector pulse" and not to worry.

I'm a noobie on this group. I would appreciate your thoughts.

Probably a 'BS' answer. More likely piston slap - less likely timing
belt tensioner.(I think this is on cars older that your model though -
anyone?)

Carl

 

[Michael Pardee]

Probably a 'BS' answer. More likely piston slap - less likely timing belt
tensioner.(I think this is on cars older that your model though - anyone?)

Carl

Fuel injector pulse? Noisy injectors don't normally quiet down as the engine
warms up, and it's rare for a single injector to be so loud you'd be aware
of it. Personally, I've never noticed injector clicks above the other engine
sounds.

I agree that piston slap on so low a mileage engine is unusual, and that it
is as audible in warm weather as in cold reinforces that a bit. I'm thinking
exhaust leak (usually caused by a broken exhaust manifold stud). Exhaust
leak "tapping" usually goes away more quickly than piston slap, too -
usually within a minute as opposed to several minutes for piston slap.

A quick survey of all the exhaust manifold studs with your fingertips (I
recommend a cold engine!) will tell the story on that, but realistically,
what do you intend to do if you find a broken stud or slapping piston? The
most practical remedy for either of those is to turn Bon Jovi up a bit the
first few minutes after you start the cold engine <8^P

Mike