Checking rail pressure while cranking

[Konstantin]

Hello, I want to check for rail pressure while cranking. I was told it has to be at least 100 psi. I do not know how to check it. I connected 100 psi gauge in rail compucheck fitting. The problem is while I crank the truck fires in about 6-8 seconds and I can not identify pressure when cranking. And with truck at idle pressure is 250 psi. Somebody told me to disconnect shut off solenoid, but with shut off solenoid rail pressure stays at 0. Any advice what could I do?

[tree98]

Why are you trying to do this? You say the truck starts right up and runs. What engine are we talking about here?

[Lonestar10]

There is a test in insite that turns actuators off something check valve in name. Turn it on and crank away.

[Konstantin]

(11-10-2019 )tree98 Wrote:  Why are you trying to do this? You say the truck starts right up and runs. What engine are we talking about here?

Sometimes out of the blue engine doesn't start. I need to crank like 3 times in 15-20 sec intervals. I am sorry it is ISX CM870.

[tree98]

Does it only do this after it has sat for a period of time? Could be the check valve is bad and bleeding off the prime.

[Konstantin]

(11-10-2019 )tree98 Wrote:  Does it only do this after it has sat for a period of time? Could be the check valve is bad and bleeding off the prime.

sometimes yes, but sometimes it does it for no reason when engine is still. especially if i try to crank it right away, without giving it 10-15 seconds ignition time. how do i check check valve?

[Rawze]

(11-10-2019 )Konstantin Wrote:  

(11-10-2019 )tree98 Wrote:  Does it only do this after it has sat for a period of time? Could be the check valve is bad and bleeding off the prime.

sometimes yes, but sometimes it does it for no reason when engine is still. especially if i try to crank it right away, without giving it 10-15 seconds ignition time. how do i check check valve?

It is not good for commercial vehicles to be cranked up like a car... you are supposed to always wait until all the systems do a self check before cranking to prevent electrical surges while the systems are doing their self checks.
similar thread... http://rawze.com/forums/showthread.php?t...2#pid30002

[tree98]

you could take it out and inspect it, but i would just replace it they are cheap enough.

[Konstantin]

(11-10-2019 )tree98 Wrote:  you could take it out and inspect it, but i would just replace it they are cheap enough.

Any idea how to access it. I removed lift pump , but i can't remove check valve. Do i need special tools do do it?