engine got louder and werid vibration

[NJGearhead666]

when i started the truck to come home from work tonight it seems like the motor got louder almost like something was not getting enough oil. I check my aftermarket oil gauge and it had almost 50psi showing on it. so I let the truck idle for a few minutes and then start driving it. It seems that when I hit about 2200RPMs the motor smooths out and sounds like it always has. but at around 1800-2200 RPMS I can feel the gas pedel viabrating like the motor is missing or something. I checked the oil and its about a quart low. I first though maybe the motor was knocking but why would it get quiet when I give it more gas?

 

[towcat]

something got into the pump or injectors?

 

[NJGearhead666]

something got into the pump or injectors?

I was thinking that, i was also thinking maybe the injector pump is crapping out but I don't get why the engine viabrates mid range but then smooths out in the upper rpms

 

[Cincinnati Guy]

I was thinking that, i was also thinking maybe the injector pump is crapping out but I don't get why the engine viabrates mid range but then smooths out in the upper rpms

Probably because the amount of fuel pouring into the IP when you idle it up.

 

[Smokey73]

sounds like the advance piston in the pump

 

[NJGearhead666]

well after a hour of me cooling off I went back out to the truck to give it a better diagnosis. the truck makes a hell of a racket at idle and I bring the RPMS up to 1500 and it smooths out and quiets down to how it normally sounds. took it for a test ride around town and it bucks bad when i hit the gas from a stop or when im rolling along and just step into it alittle. but after 1500rpms once again it runs great. ran to advanced auto and got a fuel filter guess ill throw that in on friday.

 

[LCAM-01XA]

Is it smoking grey? Spray some warm water around each injector where they go in the heads, and watch for bubbles...

 

[NJGearhead666]

its not smoking at all. i messed with it today and it seems like the noise got louder and sounds like its comming from the top of the motor.

 

[fury9]

i just had this same problem in my 99 express (thats why my idi is my daily) now i understand gas and diesel are different BUT I had three basically dead cylinders and the main culprit was cyl no 1 it acually had negative compression and i havent had the gusto to tear it apart cause its cold and i have no garage. with th3 micro camera i can see the exhaust valve is stuck open on no 1, I would suggest IMHO to do a compression test and STOP RUNNING HER until you can figure out whats wrong IMO

 

[fx4wannabe]

I had a similar problem in my 93 and it ended up I had 2 broke valve springs.

 

[NJGearhead666]

it was crazy today with it. I took it to my friends shop we messed around with it. new fuel filter and the belt tensioner broke in half on the ride there so we replaced that also but on the ride there the noise would start comming and going. Im a diesel rookie when it comes to working on them but im not scared to dive into it. I just dont know where to start or how to diagnose it.

 

[atimike]

I feel your pain

I'm fighting the exact same problem. Mine almost sounds like it's detonating in the intake. I have already taken off the valve covers(nothing felt loose),did a compression test, changed injectors(pop-tested) and return caps, drained one fuel tank and replaced with new fuel,removed the serpentine belt momentarily to eliminate water pump, etc, removed the flexplate cover to see if anything felt loose,filled up the filter with diesel kleen and ran it through. I'm at the point of taking it in to the shop because I'm out of ideas.
Smokey73, is there any way to test or free the advance piston in the IP?

 

[atimike]

try checking the flexplate

Worked on mine this weekend changing injection timing to see if I could get rid of the noise and had no luck. This afternoon I took it by the local diesel shop and they said it sounded like a broken flexplate. Driving back home the vibration got worse and next time I started it, it failed, the flexplate cracked around the outside of the crank flange. I had tried wiggling it before and it seemed tight but the shop was right on the money. If you take the cover off the bottom and pry lightly between the motor and flexplate you might be able to see movement or a crack around the OD of the crank flange. I put a clip on Youtube of the engine noise here.

http://www.youtube.com/watch?v=XhJztaw01jk

Good luck.