air compressor safety valve poping like a firecracker

It sounds to me as though it is the air governor. The governor should be located next to the air compressor. You can buy one for about $15. It only takes a few minutes to replace it. If that doesn't work and it has been a while since you have replaced the air dryer filter, you may want to change it. If the air dryer is bad it will cost a few hundred dollars. There may also be a pop off valve in the air line that goes from the compressor to the air dryer or air tank. My guess is that it is most likely the air governor. That is probably the least expensive thing to replace. You should be able to change it out yourself.

 

your problem is not the the d2 air governor , the discharge line from the compressor to the drier is plugged with carbon from oil out of the compressor disconnect the discharge line and start the truck and it will quit .i have have a few trucks in the shop for this exact same issue .Dont forget if the motor needed inframed the compressor also has wear on it . use compressed air to determine where the line is blocked , disconnect the hose at each end and where it joins somewhere about the back of the motor and see which section is blocked , you'll find its blocked solid with carbon .

 

i would bypass the dryer to test your theory, first.

are both air guages climbing at the same time?

 

did u check and see if your air compressor wasnt the culprit? my n14 did the same thing, pushing water out of overflow tank. i thought it was a head job or engine rebuild, cummins did a test and advised it was a bad air compressor.

 

i would unhook the discharge line from the compressor first, its pretty common for the line that wraps around the back of the engine to carbon up at the junction and cause this.

 

What to do if discHarge line is clogged

 

Clean or replace it. It may be swollen inside braided covering. Mine was popping this week after sitting for 10 days sub zero temps. It quit, I’m sure it had some ice formed somewhere. Usually some rubbing alcohol poured down discharge hose at the compressor connection will fix that. I’m just overdue on air drier. Time for a new one, sometime before next winter, anyway.

 

Your discharge line is probably clogged with carbon and/or your air dryer needs to be replaced. I would start looking at those first.

 

It's a pain in the ### cleaning it, but i removed it and used a coat hanger to break some of the carbon down and compressed air to blow everything out. Some times its easier to just replace the discharge line trust me.