Can diesels ping? I am hearing a sound that my 6.5 makes when just driving normal and it sounds like, for the lack of a better word, pinging. Is there such a thing with diesels? Could injectors cause a "pinging" sound?

The other symptoms I have are not so great mileage 16-17 MPG all highway going 63 and it misses every once in a while. When I cold start it (sitting overnight 30F) it will sort of miss for a while. Then when I'm accelerating gently it misses quite a bit. New lift pump, new OPS, new fuel filter, new PMD, new air filter, straight piped exhaust. I'm thinking the only explanation is injectors.

What does everyone else think?

I had missing just off idle, missing when starting cold & stalling issues, and i ended up having to replace my injection pump. Check to make sure you have 5 psi from your lift pump.

I have the pinging noise too. Im pretty sure its injectors. That explains the mileage problem too. I dont think mines making the best mileage either.

Mine does a little pinging if I listen real hard, mostly hear mine at idle though if that's what it is? I'm getting pretty good MPG 19ish & mines running real smooth...just turned 194K

I was thinking well more like hoping that noise was just that sweet sounding 6.5TD diesel music :)

Yes diesels can ping.

My 2008 does this on a long non-steep hill towing. B99 makes it louder. It is a clear "this is spark knock" sound not your normal diesel rattle. Factory tune needs a little less timing there...

Over advanced timing or fuel not lighting when injected and then exploding.

I can't see a worn chain advancing timing. So early pop of the worn injectors in effect would advance timing. Fuel economy loss from the over advance attempting to drive the engine in reverse would make sense.

Getting too hot or a hot pre-cup could also light the fuel faster and 'ping' it. Do you have a upgraded or changed water pump?

I haven't changed the waterpump and I believe it's stock still. I don't run warm ever. It was doing it pretty much the whole way to work today. Sounded almost like a gasser ping. What's weird is I can seem to only hear it coming from the passenger side floor area, but that's where I hear most of my engine noise. That seems odd to me.

If it is injectors, is it bad to drive it like this? I won't be able to change them for a couple of months (2000-4000 miles).

You can pull the injectors and have them tested rather than outright replacement. This is the cheapest route and would make sure they are the problem. Bad ones can do major engine damage quickly.

You should also inspect the turbo compressor side for parts missing and rattling around in the engine.

For the miss, have you tested the glow plugs by resistance? Also a source of loose parts...

As you have a miss this is a footnote: The OEM water pump has uneven flow issues. Like ~71% of the flow goes through the driver’s side of the block. So the gauge can read fine, but, you can be boiling over one side of the block. Even the 1995 gassers had this issue. Heath Diesel did a maxtorque article and found this flow issue on a 95 6.5TD suburban.

How hard are the injectors to get out? What can be done to fix the water pump issue? That sounds pretty scary.

Fix is high output water pump upgrade or simply replacing the OEM pump with a new updated one. I think the part numbers were updated. I know firsthand there is a TSB for the gassers to replace the water pump with an updated one from mine boiling over.

I'll have to check now. Are there any other signs that it is boiling on the passenger side?

This would be boiling in the overflow bottle. You can use a heat gun to check the block temps side to side. I am leaning toward worn injectors for the ping and reduced MPG’s. Have they ever been changed?

This would be boiling in the overflow bottle. You can use a heat gun to check the block temps side to side. I am leaning toward worn injectors for the ping and reduced MPG’s. Have they ever been changed?
Yeah, I was leaning towards injectors too because of all the symptoms. I do believe they are originals too, which is a huge sign right there.

If your injectors are original with more than 100,000 miles, i would be changing them first.

I would ,before blaming the injectors
1) check for loose turbo and injector heat shields, loose down pipe clamp or frame interference or injector lines hitting each other or the intake plenum.
All this has proven to cause a pinging sound.

2) check timing,might be a tad early