I noticed my engine is making a strange noise at about 2000 RPM. It was this weekend on a 500 mile road trip that I was on. It is more noticable when i am in a higher gear...accept 6th gear since road noises drowned out the engine noise. The noise is kinda hard to explain though. It sounds like the VP44 is making the noise and the noise cycles. When I am driving...about 55 mph in 5th gear my engine is spining at 2000 rpms. The engine makes this noise about once every second and lasts about 1/3 of the second. It is similar to the noise that the VP44 normally makes, but it is a little different noise. I dont know if that is a good enough discription for you guys to know what i am talking about. I do not get the noise at any other RPM just at 2000 +/- 50 RPM.

I pulled the codes and this is what I get;
P1693 - DTC Detected In ECM Or PCM
P0500 - No Vehicle Speed Sensor Signal

I know the first code is just telling me there is a code, but the second one I dont know why it would say that...my speedo works...odometer works...abs works....all guages work and no check engine light! By the way....my check engine light has never been on...and i have found codes multiple times in the past. Why wouldn't my check engine light turn on? It does turn on when I check the codes...but that is it. Any ideas?

My fuel pressure is above 16 psi always...even at WOT. (my guage only goes up to 16 psi) the only time it drops below 16 psi is when I bump the starter and the pumps (regular LP and in-tank retrofit pump) shut off after about 25 seconds. So I know I have enough fuel pressure. My truck has 72k on the ticker. My previous LP was bad for who knows how long, and before I put on the LP that is one there now all I had was the in-tank pump which only gave me about 4-6 psi at idle, and about 0-1 psi at WOT. So is my VP44 making this noise because it is about to die or what? Or am I confused and the noise is not my VP44, what else could it be?

 

Does the sound change or go away with engine temp? Or highier outside temps?

I've got something like yours... It's like a second light knock... Heard with low RPM's up to 2K... But mine goes away after the engine starts to warm up (140*F - Coolant). Mine is more pronouced when parked outside at 20*F mornings... But If plugged in and put in the shop then you don't hear it at all...

I'm not sure what it is but it's only there on cold mornings.

 

The noise is definately there when the engine is warmed up....I cant say that i have noticed it when the engine is cold. I would not describe the noise as a knock though....it is more like the VP44 changes the tone that it makes as it goes through the firing order. If i down shift and run the engine up to 3000 RPMs and then go back to 2000 then noise becomes more irregular and doesn't occur as often, then after a minute or so the noise goes back to its regular 1 noise per second frequency. And the noise only occures at 2000 RPMs +/- 50. No other engine speed do you hear the noise and the engine sounds normal....there is no power fluctuation with the noise either. There is a slight vibration though in the accelerator peddle when the noise is made.

 

Front u joints, just over 55mph on mine pulsing in the pedel and vibration sound. Mine did that just after I bought it.

Bill.

 

what kind of noise? grinding, clicking, humming, etc??? maybe a harmonic of some sort at 2000rpm?

 

I know it is the engine and not part of the drivetrain, It makes the noise in 4th, 3rd, 2nd as well as 5th gear....i cannot say I have heard it in 1st gear. even when I am stopped and rev the engine to 2000 and hold it i can hear the noise. It is just at it loudest in 5th gear at 2000 RPMs, and only 2000 RPMs. It is kinda harmonic, it is very similiar to the noise the VP44 makes (the loud diesel engine sound) but it is just a slight change in tone from the regular VP44 sound. Today I was driving, had it a 2000 RPMs in 5th (so I could easily hear it) and sometimes I heard it, sometimes I didnt. After I held it at that speed for a few seconds, then I could start to hear it get louder and louder to the point where I could very easily hear it. I dont have any other codes, other than those two in my first post. any ideas?

by the way...I cleared those codes last night, and just checked I have the same ones again...eveything works perfectly....why would they keep coming back?

 

the loudest sound you hear from the motor, the "rattle", is from the injection INTO the motor. the "rattle" isnt the VP-44 itself, but the fuel entering the combustion chamber and the resultant pressures.

is it the "rattle" you are referring to?

 

Yes that is the "rattle" I am talking about. It does seem that the colder it gets the less noticable it gets.

 

It's probably Timing rattle.

Try pulling out the POS Hypertech programmer.


Merrick

 

I pulled the "POS Hypertech programmer" and still have the exact same noise, no change whatsoever.

I must agree w/you MCummings, that programmer is junk, but it comes in handy w/different tire sizes. And cheap power. I am panning on getting a drag comp and that industrial VP44, once my warranty is out next year.

 

I was just thinking of this thread this morning.

The tire sizes is true. A good old Edge EZ is a much more "cooler" way to make ~60 extra horses. (pun intended)

It's going to be really hard to diangnose this one over the internet, but my second guess would be the possibility of the exhaust rubbing on something, or maybe the driveshaft throwing a curve ball.

The possibility of a exhaust manifold cracking, or leaking should be taken into account as well.

Merrick