2350 fuel pressure decay Fault code 4726
02-21-2021, (Subject: 2350 fuel pressure decay Fault code 4726 ) 
Post: #10
RE: 2350 fuel pressure decay Fault code 4726
Thanks. I will check in with an update once I get this downloaded and tested.


User's Signature: 2015 389 Peterbilt. ISX 550 18speed 3.70 gears
replyreply
02-24-2021, (Subject: 2350 fuel pressure decay Fault code 4726 ) 
Post: #11
RE: 2350 fuel pressure decay Fault code 4726
Well,
I was able to get a new “proper” program downloaded into the truck with no issue.

Picked up two loads of grain today.
I noticed that the truck has more of a knock sound to it like a fuel or injector knock especially at idle, kinda clickity clackity for lack of a better term. Much More so than the previous tune. Not sure if this is expected or if it’s caused from an underlying injector issue that I have not diagnosed yet.

The 4726 code did not come active today which is weird since the rail pressure is still dropping off. My rail block off caps are not in yet to do the tests.


Boost regulates to 32-33 under a hard pull. Although Under heavy engine braking I noticed it will climb up to 37-38 Briefly.

Temps are good, coolant sits at 190 and oil 210-220

Turbo sits at 58% at low idle if I high idle it goes to 20%


Probe temp on the exhaust manifold Climbed as high as 720deg loaded 140k lbs on a long uphill pull

I haven’t noticed any less power compared to the previous tune .


User's Signature: 2015 389 Peterbilt. ISX 550 18speed 3.70 gears
replyreply
02-24-2021, (Subject: 2350 fuel pressure decay Fault code 4726 ) 
Post: #12
RE: 2350 fuel pressure decay Fault code 4726
(02-24-2021 )SemiSweet Wrote:  ...kinda clickity clackity for lack of a better term. Much More so than the previous tune.
...

your previous tune was wound up to tight.

without a tiny bit of lash in the head at idle, the top end does not get lubed very well. Just make sure your valves are adjusted properly.


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
replyreply
02-25-2021, (Subject: 2350 fuel pressure decay Fault code 4726 ) 
Post: #13
RE: 2350 fuel pressure decay Fault code 4726
4726 code came back today. Did a cylinder cut out test and when I cut out cylinder 5 the fuel knock is completely gone . All other cylinders sound the same. I think I will start the injector return flow test with cylinder 5 and see what happens. I bet the injector is done.


User's Signature: 2015 389 Peterbilt. ISX 550 18speed 3.70 gears
replyreply





  
  
Theme by MyBB Addict
Contact Us | Rawze.com | Return to Top | Return to Content | Lite (Archive) Mode | RSS Syndication