2350 fuel pressure decay Fault code 4726

[SemiSweet]

Hi guys, My truck is showing code 4726 Fuel leakage above normal. No other codes present .Looking for any tips or guidance before I go buy block off fittings for the injector connectors as well as the test banjo fitting. Truck is demandated. Program is with Rawze for review.

What I have done so far:

Performed the fuel system leak test on insite. Pressure measured vs pressure commanded is tight all the way up to 29000psi. Shut truck off and by the time insite re connects...(rarely can I get it to stay connected so 10 -15 seconds) it is down to around 100 psi.

No external leaks.

Re seated and torqued all the connectors on the rail, pump head, and drain header.

Removed pressure relief drain line and capped. Performed the leak test again with zero drops from relief valve all the way to 29000psi.

Fuel pump roller/tappets and barrel/plunger assemblies as well as gaskets were replaced 7000km ago.

The engine shows no sign of a problem. Its starts beautifully every time with no smoke or hesitation. I have no power loss or surging of any kind.
You would think a leaky injector would make it hard starting or want to smoke a little bit or maybe hesitation on the throttle. There is no fuel dilution in the oil which is a nice honey gold color by the way.
Is it possible one of the barrel/plunger assemblies is bad. With pressure dropping this fast it should be something that shows a symptom of some sort.

I realize that I will need to run through the testing procedures that quickserve outlines to drill this down but any extra guidance is helpful.

Thanks,

[Rawze]

start by re-torquing all the feed tubes going into the head and do the test again. - After that if it fails, you most likely got a bad injector and need to use the caps to find it.

the acceptable leak-down rate is less than 4,000 psi in one minute.

[Rawze]

(02-21-2021 )SemiSweet Wrote:  ...
Truck is demandated. Program is with Rawze for review.
...

- Here is what I see at a glance with the program you sent me ...

* missing all engine mode control logic. - engine is trying to choke the exhaust all the time to warm up SCR canister and make heat to get it hot, but it can no longer see the element. This means it is going to run around all day making excess boost and heat in the exhaust. The condition to exit this warm-up mode can never be satisfied. This causes problems with the turbo spooling up way to quickly and possible over-boosting. It leads to fretted liners, possibly a cracked hear or piston in heavy haul applications, and is considered one of the more common mistakes that contributes towards a severely shortened engine life.


* All egr gas request logic is still left in place. This throws off the combustion cycle and contributes towards a shortened engine life.

* The power and torque are actually set to try and make 628HP @ 2070 ft/lbs torque. This is going to be very hard on the engine, as it is set to make the 2070 ft/lbs all the way down at 1100 rpm where it can do the mode amount of harm.

* The injector on-time tables have been jacked with to fool the ecm into giving up more fuel against its will into the cylinders above the power settings. This also fools the dash of the vehicle into a big lie about showing a much higher fuel mileage than the engine is actually doing. - typical of those places who advertise all over their over-glorified websites that "they save you 3+ mpg" type of complete lies.

* Turbo programming has not been re-adjusted for non-egr operations and is still set factory. This is usually very harmful over time. When someone does this, it is a heavy contributor of turbocharger failures.


* The injection timing is about 3 to 5 degrees (sitting at +7 and +8 BTDC in main pulse at high HP outputs) ... is too far advanced for the power level. This will be extremely harmful for a heavy-haul application... and will lead to excessive fuel impingement issues even on lower HP applications. This will eventually lead to engine damage. it is also redicoulously high at high altitude modes. It is as high as +13 and +14 BTDC. It looks like some complete didot just aded a bunch of injection timing ti all operating modes blindly ... just like in those puke deletes seen in by that horrible famous delte place in utah or that place in canada that I nicknamed "dieselSh#its". God forbid it enters the 8000+feet altitude mode.. Its sitting at +15BTDC in that mode. What a frigging hot mess!. A damned 2-stroke can't even handle injection timing that high very well, nonetheless a 15-litre 4-stroke!. These injection timing maps are not even fit to run a frigging lawn-mower!@.

* someone even had the gaul to ADVANCE FURTHER all the cold-climate injection timing tables to add more insult to injury there. - i guess they just want this thing to beat the crank bearing slap out of this engine... maybe they are trying to get more in-frame work form someone?-- WHY THE F#UK DID SOME IDIOT DO THIS???

* Looks like they left exhaust stroke fuelling on .. and then maxed out the fuel limiter. Did this idiot not know that exhaust stroke fuelling is only used for cleaning the SCR and DPF elements? -- Can anyone say --- CLUELESS!!??!? -- I though so.

* The fuel pump pressure has been raised (to 2750 bar) above the fuel pumps rating of 2600 bar.

* most of the aux.emissions and off-road emissions are still active and fighting the engine output. Was this their half-arssed attempt at trying not to blow up the engine with their horrible injection timing and other guess=-work? - That Aux.emissions manager CANNOT FIX BAD SETTINGS... it will i=only offset what is there.. I.E.> Garbage in = Garbage out! = adding insult to injury there.

* most of the hardware logic has not been hardly touched. They are using a ton of blocked faults in the ecm to prevent the ecm from screaming all of these faults that are now present in the ecm from showing up in the dash. - this is not a very good way to make a deltee file at all and can easily lead to problems that no one can find or fix at a typical repair shop due to all the suppressed codes.

There are a lot of secondary problems with it as well.. I just mentioned some of the more damaging ones is all.

==============

Typical horrible delete. Typical of those big-name shops like Puke-deletes, DieselSh#its, DeselF$ucksks, JunkBall, those auto/truck tuning sites, and all the rest.

Welcome to the bad delete club. This one has earned it front and center. Sad part is that some completely clueless truck owner probably paid a few thousands for this complete engine killing garbage too... funding these clowns who don't know their arsse from a hole in the ground.

[Rawze]

From given the day you put this horrible tune into your engine ...

and the fact that your avg. egine loads is 42.5% (according to the program you sent me) ...

and that you do heavy haul and its at 2070 trq and 620+ hp ....


I give it about 18 months or so and you will be pulling the head off it due to a fretted liner or a cracked piston .. if not sooner.


You got the money for an inframe?

How long you been driving it on this horrible tune?


and lastly.. I sure hope that exhaust can breathe well .. I hope someone made that SCR can hollow .. or bypassed the whole deal under the truck .. because this will accelerate this destruction greatly if not.


- That is what I see.


You got the $20,000 money lying around that is burning a hole in your bank? You just itching to waste money like, just so you can go up a hill a bit faster due to some ill-begotten glory?? -- because that is what someone, somewhere has done to your engine. Someone is playing f$uck-a-doodle with your trucking operations and that big-power garbage is going to cost you big-time!.

(just my opinion .. the beer is talkin') ...

This right here should be your wake-up call to get that big power s#it ideas and that bad delte OUT OF YOUR ENGINE! - You want it to pull better -- INVEST IN A BETTER REAR AXLE RATIO!

(a bit of playful sarcasm) ...
the program shows that your TRYING TO HEAVY HAUL WITH AN RTLO 0.73 OVERDRIVE TRANNY AND 3.36 REARS!!-- THIS IS GOING TO TORTURE THE ENGINE NO MATTER WHAT YOU DO! -- PUT A DAMNNED SET OF 4.11'S IN IT FOR GODS SAKE!

[SemiSweet]

Not surprised with this response on the program. The truck actually has 3.73 gears in the back. I’ve got maybe 7000km on the truck since it was programmed. Exhaust is completely straight piped, dpf and scr removed completely. I have driven the truck always above 1500rpm. Truck will sit until until I can get this resolved. I need to get in contact with someone on here that can help me get this right.

[Rawze]

(02-21-2021 )SemiSweet Wrote:  ...The truck actually has 3.73 gears in the back.
...

u sure about that? - someone needs to update the ecm program to reflect the actual hardware then. The rear axle ratio settings is sitting on 3.36041 .. just an FYI.

[SemiSweet]

I am positive on the rear end ratio . Insite also shows 3.73.

[Rawze]

(02-21-2021 )SemiSweet Wrote:  I am positive on the rear end ratio . Insite also shows 3.73.

ahh.. I see it ( I got curious, so I looked again). you have 2 settings in your for 2 diff axle ratios.
   



most trucks I see only have this as a single setting (the other one mentioned above).

just for a reference: On mine, both those settings show 3.5498 and the other setting shows this too. I have 3.55's in mine and that setting has never been adjusted since the truck was new.



even so, 3.70's is still a bit tall for what your hauling.

[SemiSweet]

I agree , 3.90s or 4.11s would be better, loaded the truck does not see overdrive as it pulls at 1500 or less which with this tune I can see would be hard on the engine.

So this guy was pretty confident in his work, he did two other trucks for guys I know . One a 2250 and one is a 871. I will be pulling there programs as I am thinking they are of similar quality.
Most likely copied from somebody else’s ECM.

Now to fix this mess..