spn 157 fmi 18

[730Industries]

Looked at a truck today. Had this code. Took for a test drive and ran fine. Probably 30 minutes total for the drive. Hot on throttle at times. Didn’t lose power. Didn’t limp mod. Nothing. No stuttering either.

During original start up truck struggled to fire up which makes sense given this code reflects low fuel pressure. It did fire on the second try and ran smooth. No knocking. No stuttering. None of that.

Upon research this code can be related to fuel pump issues. However….. the truck just had all 6 injectors replaced. The shop doing it doesn’t have the software to calibrate them though. Could this be causing this code? Given they aren’t calibrated yet? I am not familiar enough with the fuel system. So someone else’s advice in this region would be appreciated.

There are receipts for all the work done for this. Including new injectors. Seller is taking truck from 3rd party shop to kenworth to have the injectors calibrated tomorrow. However I am 300 miles from the truck now, so no easy returning.

The fuel pump was replaced at 550 and truck has 860 on it now. I do understand this is getting to its replacement time. It was replaced with new style pump.

So I guess my question is, is this code purely attached to a fuel pump grenading? Or would the injectors be causing this as the haven’t been calibrated yet?

For reference engine is the cm 2350.
VIN: 1XKAD49X8ER385380

Thanks in advance.

[tree98]

If there's a bunch of air in the fuel system that could trigger a 559 code, although it should go inactive not long after startup if everything is working right. You need to run a leakdown test on it with insite. Personally I would take the head off the high pressure fuel pump and inspect for damage. That code means the fuel system is not making the level of pressure that the ECM is asking for.

[730Industries]

(01-18-2023 )tree98 Wrote:  If there's a bunch of air in the fuel system that could trigger a 559 code, although it should go inactive not long after startup if everything is working right. You need to run a leakdown test on it with insite. Personally I would take the head off the high pressure fuel pump and inspect for damage. That code means the fuel system is not making the level of pressure that the ECM is asking for.

Ok, so my question is could the injectors not being calibrated right cause the ecm to not see the requested pressure?

I’ll call and have him have the fuel pump pulled. I’m not in the area and I have no easy to to travel back 300 miles to do it myself. Anything else to look for or at?

[tree98]

(01-18-2023 )730Industries Wrote:  [quote='tree98' pid='75277' dateline='1674042924']

Ok, so my question is could the injectors not being calibrated right cause the ecm to not see the requested pressure?

No

[730Industries]

(01-18-2023 )tree98 Wrote:  

(01-18-2023 )730Industries Wrote:  [quote='tree98' pid='75277' dateline='1674042924']

Ok, so my question is could the injectors not being calibrated right cause the ecm to not see the requested pressure?

No

Okay. I’ll see if the pump is bad bad or not. If it’s not and the plungers aren’t loose or grenaded, what is there to next check? Injectors are all brand new.

[tree98]

Like i said you need to do a leakdown test using insite. If it loses more than 4000 psi in 1 minute (with 559 you most certainly will be) you need to figure out why. retorqe the injector quill tubes, cap injectors and re run leakdown test till you can isolate 1 or more injectors as bad. Where they genuine cummins injectors or aftermarkets? Have you replaced the relief valve at the end of the rail?

[730Industries]

I’m looking at buying the truck. I don’t own it. The receipts are for genuine injectors. Just trying to figure out why the code is there so I know what I’m getting myself into. Truck is in solid mechanical condition otherwise. Lots of stuff just done to it. I don’t mind buying it and working on it, my worry is just the fuel pump having been grenaded. If that isn’t the issue, the motor should be solid otherwise. It should just be a matter of tracking down the leak. But that’s why I am here asking you guys your thoughts on that.

[tree98]

Yea if the pump isn't grenaded then it shouldn't be to difficult to fix.

[Rawze]

Here is the correct way to test the rail. Seems no one does this any more properly and then does nothing but guesses at their issues, wasting moneys. Putting this here as a reference.

ref: http://rawze.com/forums/showthread.php?t...2#pid69262