1985 6.9 IH bad sound from exhaust and intake.

[FoolhardyIDI]

My wife and I took the 85 out for a drive today. We went to the gym. then after the gym, we headed to the store to get stuff for dinner. Come out from the store. No start hard crank. Get a guy to give us a jump and cranks but no start. I think maybe heat soak on the injection pump. Get a bottle of water and pour it on the pump. Still no start. Get out my AAA card get the truck towed home. Put the batteries on the charger as they are dead from cranking the truck over many times trying to get it started. Once they have charged go to start the truck and the most awful noise comes from the exhaust and intake.

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[genscripter]

The intake noise is normal. Once you take off the air cleaner (for the NA) or the intake hat (for the turbo'ed), the intake makes that thud sound. I once started a block that I rebuilt on a stand without an intake hat, and I freaked out too. But someone on this forum informed me the intake without a hat and bowl will make that thud sound.

Here's the video of my engine running, and you can hear the thudding.

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As for the exhaust, that is odd.

 

[BrianX128]

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Sounds like injector knock to me. Have you tried cracking the hard lines to each injector one at a time to see if the sound goes away with any of them.?

 

[FoolhardyIDI]

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Sounds like injector knock to me. Have you tried cracking the hard lines to each injector one at a time to see if the sound goes away with any of them.?

I will give it a try today,.

 

[FoolhardyIDI]

This does not make sense. Go out to the truck this morning, ready to start cracking open the injector lines one at a time. Now no noise coming from exhaust or intake. Crack each line just to see and you can tell the engine starts to miss when the line is cracked but no noise. I'm at a complete loss. What could have changed?

 

[BrianX128]

Air. If you got air in your lines or had an injector line leak even a bit it will change the firing time and can make noises like that.

In my video I had a brand new ip and injectors but the awful noise was one hardline that wasn't tightened down flush and the return cap was leaking and I had another injector that had crud around the copper washer where the injector seats and it was leaking air from the combustion back up but both of those things made awful noises like what you hear in my video.

If you have an injector going out it might fire differently depending on all sorts of things if they're old and tired and same with the ip. How many miles on all of those?

 

[snicklas]

Check you oil. See if it is over-full, or smells like diesel.....

The change in sitting overnight, thicker oil and possibly tighter tolerances... if the engine was still warm yesterday even after all the time it took to get it home and started, the oil would be warm, and a bit "thinner".... could have a lifter going marginal, and will only pump up correctly with cold "thick" oil....

Or, if the lift pump is leaking diesel into the crankcase, the hot oil thinned with diesel would be "thinner" than cold, diesel thinned oil.....

Did you just have the noise, or was there a definite miss associated with the noise. If this was a chuff, it may manifest itself with a associated "miss" since that cylinder wouldn't be firing correctly.

If it's an injector, again tolerances. a hot injector, with warm fuel (the return system does actually warm the fuel in the tank as the day goes on) will be "looser" than a cold injector and cold fuel. Same idea as heat soak in an IP. Hot pump, warm fuel won't start, but a cool pump will....

Also, a small factor, what was the ambient (air) temperatures yesterday during the difficulty, vs. this morning? I see you are in Arizona, was it hotter than hell yesterday and "cooler" today? I know ambient temps can affect things. A bit apples to oranges, but if it's 80+ my IDI will start without glow plugs or ether (I don't have a working glow plug system, so yes I have been using ether CORRECTLY). But if it's 70 or below, it needs help. If air temp can effect starting, it can effect other things.......

How many miles on, and what type of oil? I've had engines (gas and diesel, including my 6.0) that I can tell in sound and performance, when it's getting close to the OCI..... My P71 (4.6 V-8) and my QX56 (5.6 V-8) which both run 5w-(20 for the P71, 30 for the QX56) oil. The lifters are a bit noiser near the OCI (P71 - 5000, QX56 - 3750) than on fresh oil. I use Castrol GTX High Mileage Oil, which is a decent oil. (P71 has 171,000, QX has 86,000) they aren't worn out, or being "cheap oil".......

 

[bugman40284]

I have had this exact same problem. My problem was the water separator wasn't sealing after I ran some soapy water through my fuel take. (long story, thought a bottle was diesel treatment....it wasn't). I did away with my separator and no more air intrusion. take it for a drive and see if it engine surges like you just gained 50hp and you can pretty much rule everything else out. Trace the fuel lines and make sure that clamps and fittings are tight. I also had a small leak at my tank selector.

 

[Macrobb]

One thing to think about - thudding/noises from intake and or exhaust can well be lifters - they will compress slowly if left under tension(valve open). Once you start the engine up, they start moving and with oil pressure, they fill back up.
Usually, it's only 1-2 lifters that 'compress' on you, but when you crank-sit-crank-sit, it'll be a new lifter under compression each time. It should clear itself up within a couple minutes of running; if not, put some MMO in the oil and that should (slowly) help - the lifters eventually get clogged with crud and stick slightly open, don't want to re-fill quickly.

 

[FoolhardyIDI]

Check you oil. See if it is over-full, or smells like diesel.....

The change in sitting overnight, thicker oil and possibly tighter tolerances... if the engine was still warm yesterday even after all the time it took to get it home and started, the oil would be warm, and a bit "thinner".... could have a lifter going marginal, and will only pump up correctly with cold "thick" oil....

Or, if the lift pump is leaking diesel into the crankcase, the hot oil thinned with diesel would be "thinner" than cold, diesel thinned oil.....

Did you just have the noise, or was there a definite miss associated with the noise. If this was a chuff, it may manifest itself with a associated "miss" since that cylinder wouldn't be firing correctly.

If it's an injector, again tolerances. a hot injector, with warm fuel (the return system does actually warm the fuel in the tank as the day goes on) will be "looser" than a cold injector and cold fuel. Same idea as heat soak in an IP. Hot pump, warm fuel won't start, but a cool pump will....

Also, a small factor, what was the ambient (air) temperatures yesterday during the difficulty, vs. this morning? I see you are in Arizona, was it hotter than hell yesterday and "cooler" today? I know ambient temps can affect things. A bit apples to oranges, but if it's 80+ my IDI will start without glow plugs or ether (I don't have a working glow plug system, so yes I have been using ether CORRECTLY). But if it's 70 or below, it needs help. If air temp can effect starting, it can effect other things.......

How many miles on, and what type of oil? I've had engines (gas and diesel, including my 6.0) that I can tell in sound and performance, when it's getting close to the OCI..... My P71 (4.6 V-8) and my QX56 (5.6 V-8) which both run 5w-(20 for the P71, 30 for the QX56) oil. The lifters are a bit noiser near the OCI (P71 - 5000, QX56 - 3750) than on fresh oil. I use Castrol GTX High Mileage Oil, which is a decent oil. (P71 has 171,000, QX has 86,000) they aren't worn out, or being "cheap oil".......

Just changed the oil with 15w40 Valvoline blue diesel the day before.
The oil level was at the same just over the full dash markings.
When we went out at first it was 105 degrees and when we got to the store maybe 107 degrees. Outside temp.
It had 130k miles when I bought it. It showed 87k on the title from the guy I bought it from and now has 167k miles. It showed 30k on the odometer when I bought and now shows 67k miles.

 

[icanfixall]

With that many miles on the engine my guess is an injector is failing causing the noise you hear.

 

[FoolhardyIDI]

Replaced injection pump and injectors when I bought the truck.

 

[FoolhardyIDI]

Just checked the timing again just to make sure everything was ok. At idle it shows 11 advanced, but at 2000 rpm it shows 7 advanced. I took it out for a 20 min drive on the freeway to make sure it was good and warmed up. I did disconnect the cold advance and the pump advance. I have the tach and time j33300 and the pick up does not work, so I use a timing light.

 

[jdla140]

I had a 94 6.5 that would do this, I thought it was something electrical for the longest time. It ended up being an injector that would stick randomly. Sometimes it would cause no starts completely, No idea why. It would thud horribly through the intake, sounded just like it.

 

[IDIBRONCO]

I had a 94 6.5 that would do this, I thought it was something electrical for the longest time. It ended up being an injector that would stick randomly. Sometimes it would cause no starts completely, No idea why. It would thud horribly through the intake, sounded just like it.

My guess on the no start issue is that maybe enough fuel would leak into the cylinder to cause a hydrolock. Since engines (from my experience) usually stop at only three different spots in the rotation, it may have only happened at one certain spot that it didn't stop at very often. I say this because from what I've seen, the teeth on the flywheel/flexplate ring gear usually have more wear in three places.