rail Pressure Relief Valve

[FDavid]

How do you know when the pressure relief valve on the rail has popped open? Anyone have this happen to there truck? Does the truck stop running if this happens, and how intensive is it to replace?



Thanks,

dave

 

[Prairie Dog]

I remember early on in this forum an 03 had this device fail. It seems to me that it shut down his engine. Dealer took one off another truck to get him going. Good thing it was warranty too because customer was told this part would be better than $1K.

 

[Tomeygun]

The way it was explained to me, was that the relief valve would open and then close after the pressure went down... But the spring was only good for like 3 times before it broke and you would need repair - I have no idea what it would do it the spring broke and the valve stayed open - #ad

 

[Gypsyman]

What happens when the relief valve opens is that the check ball is "etched" by the high pressure fuel passing it. When the pressure returns to normal the ball reseats but due to the etching the integrity of the ball to seat seal has been compromised and may cause small leaks past the ball lowering overall rail pressure and performance. The only solution is a new relief valve. Early on the only way to get a new valve was as a rail and valve assembly hence the high cost. I don't know if that has changed but it is a Star part and will come under the scrutiny of Star and the dealer.



Richard

 

[Evan A. Beck]

Only way to confirm a bad pressure relief valve is to do a return flow test with a special fitting. Any flow from the PR valve requires replacement.



Symptoms can be hard start, no start, decreased power, etc. Fuel flow test must be done.



Valve can be replaced by itself, and not with the rail. As long as its torqued properly to 45 ft-lb, everything will be ok. Surface cleanliness is critical, and don't ever use and abrasives on the mating surfaces. Price of new valve from Cummins is around $350.

 

[Gypsyman]

Thanks for jumping in here Evan. I didn't know if you could purchase the valve alone now or not. BTW, this B1-04 is nice, nice, nice!!!





Richard

 

[JDerbedrossian]

ok guys i got one for you. my fuel rail leaks where the front piece buts up against the other half right under the intake manifold, it gets wet right around the connection where the two meet, anybody have this problem. to afraid to take to dealer to check out. any info please. :{

 

[Yo Hoot]

Good reason to stay away from pressure boxes. Same issues happened with the Dmax.

 

[JDerbedrossian]

what pressure is my box putting out yo hoot, cuase i dont know exactly.

 

[Evan A. Beck]

Glad to hear everything is working out, Richard. Oo.