Engine Ping / Knock

[kcarsarebest]

2000 4.7 4 x 4 ext cab 30,000 miles, spark knock in cold weather or when towing is bad, tried new plugs, got worse, tried new gas high test and brand no better, fuel additive no help, no engine light on, gets worse on heavy acceleration or load. Gets a little better as truck warms up. truck gets 17 mpg Any help? thanks.

Moderators Note: Thread moved to Engine & Drivetrain Forum for better exposure and replies. PM was sent to thread starter of its relocation. --- Possum

[mustang67408]

From the way you have described this noise it sounds like a exhaust leak to me.
Spark knock usually gets worse as the engine gets warmer.
Exhaust leaks are louder cold, and as the gasket swells the
noise goes away. Just an opinion

[Dan T]

Not to sure what spark knock is - but I have had bad wires that got worse under load

[mustang67408]

Pinging or SPARK KNOCK or detonation is basically the ignition of fuel before or after it's supposed to be ignited. What you actually hear is the explosion (fuel ignition) of the fuel against the top of the piston. If things are working as intended the explosion occurs just as the piston reaches the top of the stroke and is starting to head back down. The explosion then pushes down on the piston. This is the basic theory behind how your engine works. When things happen at the wrong time the explosion, instead of pushing down on the piston, actually hammers the piston while it's traveling upward. Now you know why it's so hard on the engine when you're pinging. If your ears were inside the engine you'd be able to hear how hard the knock is.

[KLS]

There should be no spark knock with any modern computer controlled engine--the knock sensor and the other computer gizmos will adjust for it and eliminate the knock. If it really is a spark knock, some electronic component ist kaput.

It's probably an exhaust leak, or, hope not, something mechanical.


Ken

[woody1]

Several threads about similiar sounds.

Most related to cracked exhaust manifold. Also several photos clearly showing the problem after removal of the exhaust manifold.

[Dan T]

I have never heard it called "spark" knock before - just knock or detonation. And have experienced it several times in forced induction applications - but not N/A.

Not to sure what would cause it in this - as timing is controlled by the ECU, as well as other the knock sensor

[Scott Hawn]

I have the same problem. If I run anything but 93 octane the pinging is terrible. It mostly happens at highway speed when climbing a grade in O.D. or when you wind it out you can hear it at certain RPMs and when it shifts gears. I hate it .I have also tried some additives but had no success. My dealer just kept telling me if there was something wrong the check engine light would be on. my dealer sucks!!!! Iwould love to find a solution.

[KLS]

Find a better dealership. My 2001 V8 has never had anything except 87 (sometimes 85 in the Rockies), has never pinged even when pulling my 5200# trailer uphill at near-full throttle, and runs great.

You have some component failed on your engine. Or, could it be serious combustion chamber carbon build up from some bad fuel some time in the past? Try some Chevron Techron fuel treatment, but the real answer is a dealership that cares.


Ken

[cbsimkins]

Spark knock is an old term for detonation. As stated here, detonation is a combination of things, but your electronics are supposed to retard the ignition sufficiently to adjust for lower octane. Ignition begins before Top Dead Center, depending upon engine speed etc. When the fuel load gets too warm under ignition, the unburned fuel at the extremes of the combustion chamber spontaneously ignites. This is a detonation or knock and can damage the engine. Carbon deposites fill the combusion chamber reducing the volume slightly but more importantly insulate and provide hot spots for the temperature rise which sets off the detonation. Sometimes these are spots which will glow but that is not necessary as knocking will occur in clean combustion chambers when the CR is too high for the fuel. I would not depend upon the check engine light to protect me. I would also invest in a stethoscope to listen for exhaust leaks. Detonation will most frequently occur at high loads and full throttle, like going up a hill, and don't usually occur when the engine is cold and operating at low loads and partial throttle. If it is not an exhaust leak, have someone competent check out your electronics as something is wrong there.

CBS

[mustang67408]

Originally posted by KLS
Find a better dealership. My 2001 V8 has never had anything except 87 (sometimes 85 in the Rockies), has never pinged even when pulling my 5200# trailer uphill at near-full throttle, and runs great.

You have some component failed on your engine. Or, could it be serious combustion chamber carbon build up from some bad fuel some time in the past? Try some Chevron Techron fuel treatment, but the real answer is a dealership that cares.


Ken

I agree100% - You might also has what they call piston slap, some of the early tundras have a problem where the piston skirts make noise when cold, they rattle, the only fix is a new short block. A compitent dealer would be able to find this problem in no time at all. Look for a new dealer.

[Tundra_Jules]

I've never used anything other than 87 octane in my truck either. I do notice a slight pinging between shifts occasionally but I think this is due to the computer retarding the engine until the transmission has made the gear change to lessen strain on the transmission.

I had a cracked manifold that made a tapping noise-more so when cold but I had Toyota replace that before my warranty ran out.

[v8Toilet]

Originally posted by Scott Hawn
I have the same problem. If I run anything but 93 octane the pinging is terrible. It mostly happens at highway speed when climbing a grade in O.D. or when you wind it out you can hear it at certain RPMs and when it shifts gears. I hate it .I have also tried some additives but had no success. My dealer just kept telling me if there was something wrong the check engine light would be on. my dealer sucks!!!! Iwould love to find a solution.

What you said mine does the same thing but usually only when it's very hot outside.

[akauth]

Originally posted by kcarsarebest
2000 4.7 4 x 4 ext cab 30,000 miles, spark knock in cold weather or when towing is bad, tried new plugs, got worse, tried new gas high test and brand no better, fuel additive no help, no engine light on, gets worse on heavy acceleration or load. Gets a little better as truck warms up. truck gets 17 mpg Any help? thanks.

Moderators Note: Thread moved to Engine & Drivetrain Forum for better exposure and replies. PM was sent to thread starter of its relocation. --- Possum

I'd have the manifolds checked. It sounds like a leak. Though it should sound more like a ticking than a real knock.

The engines do knock a bit when it's cold. Definite piston knock/diesel sound when it's cold. Gone completely when it warm. Certainly doesn't happen when it's hot.

I'd put in a bottle of Techron if you think something is knocking. Though it's way early to have deposits getting hot.

If you haven't put a cleaner in though (like at every oil change), I'd think about it.

Alan

[DzrtRat]

('01 V8 running 92+ octane only) I had a similar "fluttering" noise when I stepped on the gas, sounded like an exhaust leak or a loose heat shield. Took it to the dealer and they replaced the both Exhaust Manifolds and gaskets due to warpage. At 27,000 miles it was covered by warranty. It seems to be fine now. I know Toyota's have a history of manifold problems, cracking, warping, etc., not just with the Tundra but way back to the early Carolla's which were really bad. My old '86 Toyota P/U had manifold/header cracking problems as well. It seems to be the "achillies heel" of Toyota.