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Rounded_nut · 02-08-2018, **(Subject: Low engine speed during high pressure test )**

I ran the high pressure leak down test again this morning and the pressure went to about 29k, but instead of a little extra noise from the fuel pump it was a fair bit louder and then it aborted the test due to low engine speed. I was at a normal idle and this hasn't happened before, cylinder cut out looked good, even running on the one cylinder the ecm says has a bad spill valve (number 6). Can anyone say if this new development is pointing to something other than a bad injector? I did have number 6 injector replaced about 2 years ago, can't remember if it was a reman or new, just that it came from peterbilt of Denver. I'm trying to keep from blowing money at the stealershit, I'm about 50 miles south of Witchita Kansas.

Thanks!

02-08-2018, **(Subject: Low engine speed during high pressure test )**

spill valve is internal to the injector and it basically means the injector is bypassing too much fuel to the return. change the injector.

Rounded_nut · 02-08-2018, **(Subject: Low engine speed during high pressure test )**

That’s what I was afraid of.

Rounded_nut · 02-09-2018, **(Subject: Low engine speed during high pressure test )**

I replaced the fuel injector, easy peasy and more spill valve issue, I ran the pressure test again though and it's still dumping. I'm going to wait a couple days and try again.

Rawze · 02-09-2018, **(Subject: Low engine speed during high pressure test )**

Maybe something like this?
http://rawze.com/forums/showthread.php?t...56#pid2556

Rounded_nut · 02-09-2018, **(Subject: Low engine speed during high pressure test )**

(02-09-2018 )Rawze Wrote: Maybe something like this?
http://rawze.com/forums/showthread.php?t...56#pid2556

It'm hinking something along those lines, I know Cummins has a tool to isolate an injector but that assumes only one is bad....

02-09-2018, **(Subject: Low engine speed during high pressure test )**

you need 5 of the tools to do it properly.

Rounded_nut · 02-09-2018, **(Subject: Low engine speed during high pressure test )**

(02-09-2018 )Unilevers Wrote: you need 5 of the tools to do it properly.

Was there anything special about the tester you use, besides the proper fittings? And I presume you use diesel know it?

Rawze · 02-09-2018, **(Subject: Low engine speed during high pressure test )**

I have also seen in the past, some procedures on quickserv I think for determining fuel return leak rate coming from the fuel pump, head, and other components without having to take too many thing apart. Things like removing the fuel return line from the head and checking flow, etc.

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I have seen Mr. Hag use the one mentioned here a few times...
http://rawze.com/forums/showthread.php?t...56#pid2556

I think he just tests them one at a time with it using a fitting right to each injector. Maybe he can chime in, he tracks down internal fuel leaks quite a lot.

Just throwing some things I have seen out there that may be helpful.