2250 Carnage Pictures

[Rawze]

(04-09-2017 )doarmihai Wrote:  on quickserve this is the right procedure for High-Pressure System Leak Down Test
i don't know where rawze got his info
Connect INSITE™ electronic service tool.
Operate the engine.
Perform INSITE™ electronic service tool Fuel System Leakage Test.
Monitor the fuel rail pressure. Fuel rail pressure will rise and stabilize. This could take up to 5 minutes.
Shut the engine OFF and wait for it to completely stop.
Turn the keyswitch ON quickly.
Record the fuel rail pressure measured value. This is the first measurement.
Monitor for exactly 30 seconds.
Record the fuel rail pressure measured value again. This is the second measurement.
Subtract the second measured value from the first measured value.
A decay in fuel pressure greater than 1500 bar [21756 psi] in 30 seconds is an indication of a high-pressure fuel system leak.
See the appropriate troubleshooting symptom tree for repair direction.

You are referring to procedure https://quickserve.cummins.com/qs3/pubsy...html#STEP3

Other than the PSI in my video that I made more than 2 years ago, I said 4,350 psi in one minute and cummins now proclaims a completely ridiculous 21,756 psi in only 30 seconds (I think they may have updated it in quickserv since the video has been made), I would say that my video is more accurate than the BS cummins proclaims in this procedure. That or it is a typo. An injector or relief valve would have to be blown out for that much leakage, and the pump would possibly even have trouble keeping up at idle if it were that bad.

(04-09-2017 )doarmihai Wrote:  ...
i don't know where rawze got his info
...

Rawze based this more than 2 years ago from the information that was provided at that time. It USED TO SAY 150 bar (2,175 in 30 sec/4300 psi on one minute), not 1500 bar.

If anyone wants to go around and say their rail is not leaky if it is bleeding 4,000+ psi in one minute, then they have some serious misconceptions towards what is the norm. In fact, MOST TRUCKS will not leak even 200 - 300 PSI in a minute when the system is in good shape. 21,000 PSI in half that time would dictate that the whole system would leak to ZERO PSI in about 45 seconds or less.

If your engine is leaking down more than 4,000 PSI or so in one minute,.. then YOU HAVE SOME SERIOUS ISSUES! Especially if it is an injector. As it gets worse, it can eventually lead to lead to flooding of the cylinder after the engine is switched off, resulting in hard starts and even possibly hydra-lock if it gets severe. Also the pump gets over-worked if you have any kind of decent rail leak, so if someone wants to stick their head in the sand and disagree with this, then go have fun. I have seen engines run rough, have excess soot and poor fuel mileage where an injector was leaking only about 2600 - 2800 PSI in one minute, so I thought that cummins original value of 4,300 was actually even a bit lenient back then, but 21,000? -- in 30 seconds? -- Must be a typo!. That or they got tired of making warranty claims is all I can say. It is likely supposed to be 150 bar, not 1500. That is what the original value that I read used to be.

Fine out what is leaky. Make sure it is not an injector and fix what is leaking. Most of the time it is simply the bypass valve that has gotten weak or trash in it but sometimes it is an injector, especially as the engine gets older and it effects fuel mileage and everything else.