Strange Noise........Injector?

[403turbo]

Ok this is what I've got.

After a cold start, even when outside temps are warm the engine sometimes has a loud knock. Now hold on before you jump to conclusions....this isn't the normal "cold diesel seems louder than normal knock".

This is an extremely loud knock that seems to occur after I'm rolling a mile or so and I stop at an intersection. The first split second I touch the go pedal it sounds like the pilot injection turns off and then back on. Just a change in the sound of the engine, no hesitation, no loss of power. Just two or three louder than normal knocks then all is well.

The weather is warming up(finally) but its not quite AC weather so the windows are down and I am hearing it more.

Any thoughts? Is my truck going to start spewing fuel all over and leave me stranded somewhere?

Thanks

[heartbeatcanada]

I have had the same thing happen to me a handful of times as well. I was just chalking it up to not letting it warm up enough, as it seems ever time it has done it, i just started the truck, let oil pressure build and leave. The only thing that puzzled me was it did it in the winter, then quit and then returned. Now i probably don't let the engine warm up enough, about 2-3 times a week, and it doesn't do it all the time. Does this sound about the same 403 turbo? Maybe somebody with some diesel for blood would be able to let us know what possible things we should or could be looking for as in problems or preventative solutions! Thanks :rolleyes:

[D-max Man]

It may be a due to an EDU (FICM) starting to go bad.

We had one that would run fine up to 1300 rpm and above 1350 rpm but between the two, it knocked like crazy. GM actually ended up buying it back before we were able to get ahold of it and solve the problem.

[403turbo]

Yeah that sounds very similar. I do the same, let oil pressure come up...usually wait for voltage to stabilize so that the various heaters(air,fuel) are off and then its into gear and rolling. This problem is hit and miss...not every time and it doesn't seem to be getting worse. I think I am just hearing it more because the weather has been warm and the windows are down.

I do have an older version of the Juice 3. something....the fuel filter gets changed every 10K and I have always run either Howes or Power Service fuel additives.

Maybe I'm just being paranoid but I am sensitive to new noises from my engine!

[mackin]

Just wondering ...

Do you run an additive ??? I use to have a idle knock that if I just leaned on the go peddle a hair it would disappear... I then started running a additive and sence has never returned ... Mine was most audible warm to hot,normal operating temp ...

Mac

[heartbeatcanada]

I do use an additive, but i'm not as religious as most of you. I forget probably 50% of the time :eek: too much on the mind.

I run the 4.61hot juice, but know for a fact that it does it with the juice not hooked up. This past winter i took the juice on and off experimenting when snow plowing, and know it was off at least a couple times it did happen.

Am replying to both threads, and am posting some #s on the other one. Later

[ratlover]

Why did you try unplugging the juice when plowing and what did you find?

[heartbeatcanada]

Ratlover

I just wanted to see what kind of a power difference there was, egts #s, and fuel economy. My findings were the obvious. With the juice a flowin on the lower levels of course it had more power than anyone would need pushin snow, though at times too much as traction sometimes became a problem. Egts were pretty much no different as your not wot, and fuel economy was a litle better with the juice, but nothing worth writing home about. I did my testing based on the same type of snowfall(how much and wet snow) and 2640lbs of salt in the box + tailgate salter. With that weight in the box the juice made a huge difference, almost didn't know it was back there(kind of scary). Either way its one hell of a truck, its surpassed my expectations. Later smile.gif

[ratlover]

I am waiting on my reg cab 2500 D/A :( Its supposed to be here thursday :cool: I cant wait!

Will be running a 8'6" Fisher V. no spreader.

I will be juicing her but I figured I will do it after break in. I just was wondering if there was anything to consider about running juiced in the snow other than the obvious traction issue ;)

Still debating if I want to order exhaust now and hopefully have if for install durring the 3 day weekend. Probably just strait pipe it this weekend and see if it sounds too much like a ****ed of concrete truck

[heartbeatcanada]

Ratlover

You will love your new truck for plowing. I use a 8ft Artic plow with removable wings that make it a straight blade or a box plow. Never take the wings off, and can have snow 8ft wide 4-5ft high and 5-6ft out and the truck pushes it no problem. Probably comparable to your v plow. Good luck on wiping the grin off your face when you pick it up. I'm still grinnin.
Later smile.gif