I have an all stock 2001 F-250 with a 7.3 Powerstroke that has one loud cylinder on the right (passenger) bank, either #5 or #7. It seems to be injection-related. It makes a noise that does not seem to be a mechanical (valve tappet, piston, wrist pin, or rod bearing) sound. It is the same at all RPM's and all throttle settings. It seems louder at idle only because there is less other noise to mask it.

The truck has 267,000 miles on it and I bought it eight months ago. I have put about 1,000 miles on it since. It has an automatic trans. and has been getting about 14.5-15 mpg with light loads, and doesn't seem to change whether on the freeway at 70 mph or around town. It starts right up and runs smoothly, with no indication of reduced power.

Since it has so many miles, I just replaced all the injectors with Ford remans., and since I was in there anyway I replaced the glow plugs, UVC harnesses and the valve cover gaskets. I also installed the Dino Fuel cross-connect kit and a High Pressure Oil cross-connect. After this work, I think the truck has more power, but it wasn't bad before.

Because of the cross-connect, I put in all AD injectors. There was one AE injector installed, but it was in Cy. #4, instead of #8 where it should have been. After I did the work, the noise did not change.

I would't mind the sound if all the cylinders were the same. I just don't like having just one "cummins" cylinder! Does anyone have an idea?

Jock

 

Are you 100% sure all injectors are torqued/seated correctly?? How 'bout the rocker arms?? Did you torque the rocker arms while you were in there?? They seem to come loose after a while...

 

The way you can tell if it's an injector is get up to speed so that you are in O/D with the torque converter locked. Let off the pedal and coast. When the torque converter is locked and RPM's drop below ~1900, the PCM will shut the injectors off. If you still hear a tapping sound, it's a mechanical knock. If the knock goes away, it's an injector.

I have an injector knock that you can hear at idle on either the #2 or #4 cylinder. When I do that test, the knock goes away and it's completely quiet. That's how I can tell. It still passes every test I throw at it, so it's working fine. It's just making a bit more noise than the others. I've heard a lot of PSD's with the same knock.

 

Thanks Izzy351 and Pocket! I double checked and found that everything was assembled properly. I tried Pocket's test, and the noise goes away in coast in O/D as the RPM's drop. It looks like I'm chasing an injection noise. I wonder if there is something in the ICM circuit that is affecting one injector? I wouldn't be concerned about it, but this one is so loud that it's kind of embarrasing.

 

Have you access to a good code scanner to try an injector buzz test? That should narrow down if you are chasing something in the electromechanical section near the solenoid at the top or it's electrical feed lines or somewhere else in the injection system. Does the pitch change with RPM? It sounded like you said the sound level didn't change, just wondering if the frequency did. Also looking at some live data as the thing runs might be interesting. Also was this problem there before the injector change?

Thanks
Chad

 

Yes, the noise was there before I changed the injectors. The noise seems to be in the same cylinder (#5 or #7) and seems to stay about the same volume (it just is covered up by increasing road noise as the speed increases) and of course follows the RPM. As I reported earlier, I replaced all the injectors, both UVC harnesses, both valve cover gaskets, and all the glow plugs. I was hoping that the "fresh start" would find whatever was causing the noise.

Unfortunately, I do not have access to a scanner. I will try to find someone who has one, but I'm in an area that doesn't seem to have much in the way of Powerstroke support. I think that by replacing all the parts I did, I have eliminated everything inside the valve covers. Could there be a computer problem?

Thanks,

Jock

 

You probably would do better at eliminating the injector noise if you were to eliminate all the quick connects on the fuel feed line from the fuel tank to the fuel pump inlet.
Due to a poor design by Ford a lot of air gets introduced to the fuel stream via those quick connects. The o-ring seals do a great job of keeping fuel in under pressure, but a terrible job of keeping the air out of the fuel being drawn toward the fuel pump inlet.
Just cut the flex lines off of the end of the steel lines and install some good fuel injection rated hose with screw clamps.
It will never get rid of all the cackle, but it will reduce it by quite a bit.
.
Also, if you didn't do it when you were inside the valve covers, I very highly recommend that you go back in and retorque the rocker arm pedastals. Half of mine were loose at 90,000 miles when I did mine.

 

For the noise to be made by entrained air, one cylinder would have to be in a critical state, as far as injector or control systems. Since I changed all the injectors and the internal engine wiring, I would have to have another bad injector in the same hole, or a wiring/control problem outside of the valve cover. I installed the Dino Fuel cross-connect in part to address the entrained-air/cackle issue (I really did it because it made sense to get rid of the "dead end" fuel rails for several reasons, one of which is to use the same injectors in all positions) and to have a better control of the fuel in the rails.

Soon I will be installing a service body on this truck, and when I take the old pickup box off I intend to do the in-tank mods. I will attack the fuel lines then. I am thinking of installing a pre-pump filter and removing the in-tank pickup screens. I will have to decide if I want to get rid of the stock fuel filter and mount an indstrial filter on the frame beneath the cab.

The results of the "Pocket" test make me more assured that there is little risk of imminent damage. I'll just keep running it and see if I can fiddle around with enough things to accidently fix it.

I never noticed a "cackle", only the one cylinder firing louder. Does anyone have a comment on the AE injector being installed in the #4 hole instead of #8 where it belonged?
Jock

 

Either an idiot not knowing what he is doing or someone trying to chase down a problem that may even end up being mechanical.

Moving your suspect injectors to the other side should move the bad/loud injector to the other side too. Since you had it there before, and still have it after replacing injectors, I have my doubts about the injectors being the problem.

 

I agree with Tenn01PSD350 that changing injectors proves that the problem is something else.

When we pulled the old injectors, they had large amounts of carbon on them. Is it possible that excessive carbon deposits in a cylinder could cause this noise? Since all the cylinders had about the same amount of carbon, there would still have to be something affecting the one more than others.

If carbon is a possibility, perhaps I should start a new thread with that as the subject.

Jock