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

[Kennedy]

Sounds like an injector. Best is to look at the balancing rates when it occurs, and/or do a cylinder power balance and see which hole stops the knocking...

[heartbeatcanada]

JK or anybody know what kind of balancing #s we should we getting? :confused: Was reading my data from the predator this weekend and they were all +4 with the exception of 1 which was +5. Are these #s in the exceptional range or should they all be even across the board? Maybe time to get a new set(75hp injectors) put in so i can sleep at night! :D

If an injector was going south would it give a different balancing # one time and then be within specs. another time? I will keep a closer eye on this with the predator plugged in and see what it tells me. Later :rolleyes:

[Kennedy]

Make sure you are looking at the balancing rates and not the pulse time. The pulse time will be .45ish.

Balancing rates will be on both sides of the scale, and a good set seems to have all less than +/- 2mm.

Engine must be warm and in neutral/park.

[heartbeatcanada]

Just went out and recorded some #s from the predator as per what JK stated. My bad,i got the pulse time and the balance rate switched. Here are the #s

Base PWM

#1 0.3
#2 0.4
#3 0.3
#4 0.4
#5 0.4
#6 0.5
#7 0.4
#8 0.4

I would say those #s seem allright, will keep an eye on #6. One other thing, if i rev the motor to 1000pm,they all read 0.4, rev it to 2000rpm or higher and they all read 0.4.


Balancing Rate

#1 -1.41 to -1.72
#2 0.38 to 0.55
#3 -2.32 to -2.49
#4 -0.76 to -0.98
#5 -1.74 to -2.05
#6 1.08 to 1.40
#7 -0.72 to -0.94
#8 -0.32 to -0.69

Same thing, i rev the motor to 2000pm and they all go to 0.82 if that means anything. :confused: Anybody else got any #s too compare to. Something i will be keeping an eye on. Do those #s sound allright or should i be making a trip to the dealer?

403 turbo Do you know anybody with a predator or tech 2, to pull some #s? Maybe it would set your mind at ease or maybe it would warrant a trip to the dealer? Either way i think i am going to speed up my thinking on the mega filter.

:cool: Later

[dmaxalliTech]

Heartbeat, those no's look pretty good. It would be interesting to see them when you are having trouble though. I bet they are different. Off idle, balance rates will drop to near zero. Normal

[heartbeatcanada]

dmaxalliTech

Thanks for the info. Re-assuring to know. Will try and remember to plug in the predator in the mornings to hopefully catch it when it acts up. If i catch some numbers i'll post. Later

[403turbo]

No, I don't have access to a tech 2 or predator. I am going to start looking into some better forms of filtration too. The thought of loosing $600 injectors keeps me up at night. At the same time if I freaked out every time my truck made a new noise I wouldn't ever sleep!

I do my best to protect it, but at the end of the day its a truck and a good one doesn't need to be pampered, well maintained yes, babied, no.

Thanks to everyone for the insight.