This is my first 92 D250 4x4 dodge diesel and I love it.

When i first start the truck in the morning, sometimes the engine noise is really quiet. For a diesel I think it's almost to quiet, hence the purr. In maybe 30-60 seconds it change very abruptly to a load, what I think is an injection rattle. Outside temp does not seem to effect this condition it just seems to do it when it wants to. I wonder if this has to do with the fuel heater and the PCM or the KSB solenoid. One other thing I thought it could be was air getting into the fuel. If anyone can tell me how the truck should sound at idle on cold start and first 1-2min of driving and or have had or still have this condition I would really appreciate it.

This does'nt sound right to me and kind of has me worried.

The truck runs great and sounds really nice when it is purring but I don't know if its normal.
I have installed a 16cfm housing and made slight pump adjustments but thats it. This condition was there before

 

Sounds like the KSB kicking in - but that should only happen when the air temp inside the manifold is below 90 degrees.

 

Thanks Wannadiesel. When it kicks in is that at key on. Or is it kicking in after the 60sec that Im getting the rattle

I have the Factory dodge manual for this truck. It says the KSB should never have 12v only about 8v. It says there should be a resistor in the circuit which isnt there. Talked to a dodge tech and all he said was if it aint broke dont fix it. Not alot of help.

 

Hi, Im not sure if you are having the same rattle as my dad is but I just talked to him and it sounds as if you two have the same truck & possibly same issue? I was wondering if you have found out what was going on with yours yet? I just posted a question on this topic today. Thanks! Maybe if either of us get an answer we can help eachother out!

 

I had the same issue a couple years ago. Going down the road the engine note would change at random. Same at idle, sometimes noisy, sometimes not. If it was a gasser I would have said the timing chain was jumping back and forth a tooth. Unplugged the KSB and the problem went away. Turns out the manifold air temp sensor thingy was bad and turning the KSB on and off at random.

Try unplugging the sensor and see if it helps.

 

Thanks. I'll try diagnosing the KSB

 

Just leave it unplugged for a few trips and see what happens. If it keeps rattling, it's not the KSB.