extra loud ping/detonation

[jag7720]

I posted this on diesel place too...

1985 M1009 6.2 25,000 miles

This is going to be hard to explain.

I have been noticing an extra loud ping in my engine. It only happens under load.

When I am cruising at 30 or 40 mph or highway speeds. If I lift off the accelerator it goes away... If I give it full throttle it seems to lighten up.

It is does not have any rhythm and it "sounds" like is is a single extra ping.

It does not go away when the engine is up to temp.

I want to say the it almost sounds like the loud pings you get on a cold morning and the engine is on high idle while you are driving.


Anyone have any idea what might be going on and what I can do to make it stop?


Thanks

 

[doghead]

bad injector?

 

[lavarok]

Bad fuel? I recently had a problem with some bad diesel from a small station off the interstate. I thought my engine was getting ready to fall apart. Luckily, it was only 3 gallons. I put some fresh off road in once I got home and within 10 minutes of driving she sounded purty again.

 

[jimm1009]

extra loud ping.

I have heard of th low sulfer fuel doing this but I am no diesel expert.

You might consider a fuel additive to improve lubricity of the fuel.

Also check the "rough timing" of the injection pump.
The top of the engine has a timing mark and so does the pump.
The lines should be lined up together if everything is good.

It's easy to do. Just pull the air filter assembly and take a quick look.

Jim

 

[jag7720]

bad injector?

In what respect?

as far as bad fuel... doubtful as it has been doing it for a while and I have used fuel from several different places...

low sulfur... maybe... what additive could I try to bring the lubricity up?

 

[doghead]

Opening to soon or sticking. Get them cleaned/tested or replace them with new or rebuilts.

 

[jag7720]

Two words... Diesel Purge.

That was the best $12 fix I have ever done.