Is the EGR. Delete good

someotherguy said:

I'm sure whether or not it will ping when failed depends on the failure mode.

If removed, which can easily be different operating parameters than failed (no EGR action at all vs. EGR action of inappropriate amounts/under incorrect conditions), you no longer have exhaust gas (essentially inert gas) helping to cool the combustion chamber, so you can be more prone to pinging.

Richard

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I found this thread you posted on Chevy Talk years ago when I first got my truck and was having the EGR code all the time and you explained what it does and how to fault test it. https://www.chevytalk.org/fusionbb/showtopic.php?tid/258416
I thought this may help answer a lot of these responders questions. The reason it was setting error codes on my truck was due to the open exhaust messing with the ECU test procedure giving a false fault code.

Late to the game, but the issue of PINGING got my attention. Most posts here and there, only talk about the EGR valve. It is a key part to prevent pinging, so deleting it can cause damage.

Well here is my pinging problem. 1989 Chevy K1500 5.7 110k. Pings under load. Knock sensor was disconnected, but connecting it did nothing. EGR valve tested good, however the vacuum to it was only 10". These engines have intake manifold gaskets that fail. So I pulled mine today (original never bbeen changed) It was heat hardened and a bear to clean up. Gasket came off in pieces so unable to verify if leaking. However, I am glad I did because the EGR passage at the head was absolutely clogged shut with carbon. That means the EGR could not work and hopefully is the cause of the pinging.

So if your engine pings, pull the intake manifold gasket and check the EGR passage.

Russ B said:

1989 Chevy K1500 5.7 110k.

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Russ B said:

Pings under load. Knock sensor was disconnected, but connecting it did nothing.

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Tap on intake manifold or cylinder head with small hammer. Listen for engine RPM to decrease; or watch the timing retard using a timing light.

Sounds like the knock sensor circuitry was defective.

Russ B said:

if your engine pings, pull the intake manifold gasket and check the EGR passage.

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The EGR passages can be tested by lifting the EGR pintle at idle, listening for engine RPM to drop due to air/fuel dilution.

EGR passage plugging is somewhat common.

Schurkey said:

Tap on intake manifold or cylinder head with small hammer. Listen for engine RPM to decrease; or watch the timing retard using a timing light.

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Apparently depends on year model; some must be in gear for this test to work. At least, according to Mitchell. Factory service manuals probably mention this where applicable, but I haven't looked in years.. just something to keep in mind if you're doing the hammer tap trying to simulate pinging but you're not seeing any knock counts. Lift and safely support the vehicle and place in gear.. I'd probably jam the parking brake to the floor, too.

Richard