Diagnosing Engine Sound (spring/ratchet)

yrenner · #1 04-14-2022, 08:30 AM

Sounds like a ratchet or one of those springy door stops in your house. Sound is loudest and most pronounced from 1250 rpm to ~2000 rpm and then it's harder to hear as the frequency increases. But I can still hear it around 50 mph. As soon as I let off the gas, it sounds like a door stop that got bumped and rattles for about a second. I can also hear it at times while coasting and coming to a stop, when it sounds very much like a consistent ratcheting sound.

Background: I've been having a rough idle and misfire only while idling (750 rpm) and only after the engine is warmed up. I think the sound I'm hearing from the engine compartment may be causing my problem. I do have a noticeable crack in my exhaust manifold (see here) but the sound I'm hearing is more mechanical, corresponds with the RPMs, and doesn't go away after the engine is warmed up.

Edit: 2006 Ford Ranger XLT 3.0 V6

12 Deg North Industries · #2 04-14-2022, 11:08 PM

Does it do it in gear only or even in neutral?

If it will do it without moving, its not a moving issue. If it does it while in park or neutral, sounds like you gonna need a buddy or the G/F-Wife to come rev the engine up while you poke around under the hood.

It may be more obvious but if not, you can always take a long screwdriver, Radiator pick tool, even a smaller prybar put it on the valve cover(s), on the cracked manifold, block, etc and push the handle sort of in your ear socket, the noise will transmit through like an engine stethoscope, Poor mans version.. It may help, if not now in later issues, but it may be more obvious than that.

yrenner · #3 04-15-2022, 11:14 AM

So it's not a moving issue. I can still hear it loud and clear in park, especially after the engine has been running for a while; not so much or at all when the engine is cold.

I didn't have a long enough screwdriver so I bought a cheap mechanic's stethoscope. The fuel injectors sound fine (the ones I can get to without removing the intake manifold) and I couldn't hear anything coming from the valve covers or from the cracked exhaust manifold. But I wasn't reving the engine so will have to give that a shot next. Thanks.

12 Deg North Industries · #4 04-17-2022, 02:33 PM

Quote:

Originally Posted by yrenner

So it's not a moving issue. I can still hear it loud and clear in park, especially after the engine has been running for a while; not so much or at all when the engine is cold.

I didn't have a long enough screwdriver so I bought a cheap mechanic's stethoscope. The fuel injectors sound fine (the ones I can get to without removing the intake manifold) and I couldn't hear anything coming from the valve covers or from the cracked exhaust manifold. But I wasn't reving the engine so will have to give that a shot next. Thanks.

You should be able to remove the plastic cover for the throttle body and gain access to the T/B cables and raise the RPM to do that from the engine bay.