Another DI question

[blackandtan]

I have an 02 RXDI that I have been trying to figure out the fuel system on for a while. I pulled the fuel pump and cleaned it cleaned the injectors and changed the fuel filters and now have 107 psi like it should. But after I ride it for about 10 minutes it will blow a hole in the small air line coming off of the air compressor. Does anybody have a suggestion for what to check on it?
One of the cylinders is low on compression from the rave very slightly hitting the piston so I know I have to do the top end but I would like to figure this air line out before I do that.

 

[bdesim2]

Is the line that's blowing oem? Or did you replace it?

 

[blackandtan]

I replaced it. it was blown when I got it so I put a piece of parker flexible air line on it rated for 300 psi and 200*

 

[bdesim2]

I personally have never had one blow or had to deal with it... but I have heard that when that line is replaced even with high pressure line this issue happens. The oem stuff is very good. You may want to try an oem hose and see if this fixes the issue. Search the forum here for threads on this exact topic. There have been a few recently.

Hope this helps.

 

[stout890]

Maybe a bad pressure regulator? The compressor makes quite a bit of pressure well over the 80psi needed but the regulator should dump excess pressure overboard.

 

[blackandtan]

I could be wrong but I would think if it was the regulator the fuel pressure would be to high but I have been wrong before.

 

[bdesim2]

As the air pressure rises in the rail to 80 psi the fuel pressure rises to maintain pressure plus 27 psi. That's where you get the magical 107 psi number. If the air pressure was too high the fuel pressure could be too low causing the injectors not to flow fuel.

I would look at the regulator as posted above and change out that line to the oem hose.

 

[stout890]

I would think the fuel pressure would be to high if it was the air pressure regulator failing to release excess pressure. From what I know the air pressure acts on the relief valve for the fuel which is set at 27psi so as the compressed air acts on the fuel pressure regulator it increases (equal to the air pressure+27 psi) the pressure in which it dumps excess fuel therefore allowing the fuel pressure to build. So the 80psi+27psi=107psi

So basically if the air pressure relief valve failed you would see high fuel pressure
I can't think of a reason other than too much pressure for the line to burst though. Rubbing maybe?