Strange breathy sound over 5k RPM...

[begleysm]

Hi all,

I've searched google a bit but I'm not even sure what to search on.

I had a miss-firing 4th cylinder & I repaired it by simply changing out the sparkplug. I haven't really driven it yet but it, obviously, significantly better just from the smoother idling. (Perhaps it isn't completely repaired... read on).

To test it a bit I revved up the engine up a bit &, oddly, at about 5000 RPMs the engine started sounding "breathy" going "putt putt putt putt putt", very similar to how it sounded idling when cylinder 4 was misfiring.

When I go out tonight I'm going to gas up & dump in a bottle of Fuel Injector Cleaner.

Any ideas what is going on?

Thanks,
Sean

 

[bluestream1]

I never rev my engine over 2500RPM. With the crappy timing chains they are prone to go ...Kaboom

 

[sport97]

If you said it sounds like it is missing, it probably still is. The light may come back. Could be low compression, or bad injector maybe?

I never rev my engine over 2500RPM. With the crappy timing chains they are prone to go ...Kaboom

Not sure how you don't go over 2500 RPM's. Even under normal accelerations I hit 3k RPM's. That may be to do with my gear ratio though. Mine has kissed the 6k RPM mark PLENTY of times, still ticking. But I agree, probably better off babying it, I am just tough on things haha.

 

[yavapaires]

Hi all,

I've searched google a bit but I'm not even sure what to search on.

I had a miss-firing 4th cylinder & I repaired it by simply changing out the sparkplug. I haven't really driven it yet but it, obviously, significantly better just from the smoother idling. (Perhaps it isn't completely repaired... read on).

To test it a bit I revved up the engine up a bit &, oddly, at about 5000 RPMs the engine started sounding "breathy" going "putt putt putt putt putt", very similar to how it sounded idling when cylinder 4 was misfiring.

When I go out tonight I'm going to gas up & dump in a bottle of Fuel Injector Cleaner.

Any ideas what is going on?

Thanks,
Sean

Could still be a plug miss, or, more than likely hitting the rev limiter. I'm not sure it has one, but that would be my guess. 5 grand not under load on a stock engine, if held there? Kinda dicey if you ask me.

 

[sean kane]

The rev limiter will kick in somewhere between 5k and 6k so you are probably hitting the rev limiter.

I would take it for a drive and see how it performs.

 

[sport97]

Could still be a plug miss, or, more than likely hitting the rev limiter. I'm not sure it has one, but that would be my guess. 5 grand not under load on a stock engine, if held there? Kinda dicey if you ask me.

Good point, I was thinking it was under load. Don't rev like that if its not under load. That is a good way to blow something apart in there.

 

[begleysm]

Thanks for the replies.

It was not under load when I did this. Not saying it is good for it but I've done the high rev thing in the past (after working on the car) & never heard it do this so I don't think it is a rev limiter.

I drove it about 40 miles yesterday on surface streets & the highway (up to about 75). No missing, no light.

Unless anyone has any specific experience or ideas, I guess I won't worry about it unless it becomes a problem. I rarely ever hit 5k during normal operation anyhow.

Thanks,
Sean

 

[windsors03cobra]

Probably not even designed to rev that high, a 14 year old low performance motor that was ill conceived to start with and one that has probably been abused and neglected.

Keep the revs down unless you want your motor to say "goodbye" instead of being weezy.

 

[bluestream1]

Not sure how you don't go over 2500 RPM's. Even under normal accelerations I hit 3k RPM's.

Thats easy; I drive it like a Granny.

When I get a few drinks into me and feel like livin on the edge I get the revs up to 2700