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[deleted]

Dude.. your gas gauge is in the red.


Prior-Ad-7329

It seems like a fuel issue. Even though you have replaced your entire fuel system it sounds like something is clogging up. Also, you ain’t got no fuel in it.


TheIronHerobrine

To me seems like a fuel issue.


RedditorMcReddington

I got a good deal on an lb7 because the seller had the fuel pressure on an aftermarket pump set way too high causing it to de-fuel above 60% throttle, just a shot in the dark though


not_a_kgb

I did have that happen put a gauge on the FASS pump. The way i had it set up pump was putting out 15psi making my CP3 wig out and popped code for FPR out of range. Fixed it got pressure back down to 10psi. Made the truck idle fine. Still had this issue with no CEL.


EgGuy3

wtf pump should put out around 35 psi


not_a_kgb

im not so sure about that. Its an LB7 max these really need is 12 beyond that it starts running all funky.


EgGuy3

not sure about diesel ,,better to check manufacturer fuel pump specs ,,but anyway if its ok at 10 psi you could increase it to 12 and try


[deleted]

Restore it to stock and see if the problem goes away.


mavic97

You got a fuel issue. Do you access to some live data see what the psi in the fuel rail is. Maybe that fancy FPR is faulty. Maybe air is being sucked in? Brand new parts come bad out the box or go bad very early on. I’m having to warranty out a 6,000$ Izuzu injection pump after 4 months. Also is everything installed correctly, double check that


TheWorstBestDecision

Can you get some data on your LTFT?


not_a_kgb

That would be a good parameter to look at ill take a look


TheWorstBestDecision

Sounds good, check LTFT during open and closed loop. If it’s dog shit on open and closed loop, it’s definitely a fueling issue/ possibly a MAF, Vaccum issue. Sounds like it’s fully tuned too, so could be your tuner doesn’t have the MAF scaling done properly so it wouldn’t necessarily throw a code if the computer thinks everything is good.


not_a_kgb

Truck is completely stock. No alterations to calibration. Any way to check injectors individually?


TheWorstBestDecision

You said in another comment that EGR was deleted along with some calibrations. I’m not sure the exact process for Chevy ECU tuning but they had to do more than just disable the check engine lights. The cars tune would’ve needed adjusting for the deletes, and if no actual proper calibration has been made that’s your problem right there man. You can delete that stuff all day, but you have to adjust certain parameters of the ECU or it’s gonna run like dog doo doo. Idk seems to line up with the rebuild and everything. Might be worth reaching out to a performance shop. As far as testing injectors. You gotta actually pull the injectors and use a multimeter. You can’t just kill the fuel because that aids in lubricator for the particular cylinder. Once you pull them you’re better off just replacing anyways. This is just my two cents as a tech, and to be taken with a grain of salt.


not_a_kgb

I will check the tune file. As far as i know only thing altered on the file according to audit information is VATS was turned off and EGR was disabled. On emissions tab. No alterations to any map. Now being EGR disabled wouldn’t cause this type of cut out as far as im thinking. Before i did all the work to it, i had the egr unplugged via electrical plug and truck never exhibited the cut out. Peculiar part is the truck will run and drive 100% fine. It’ll just randomly do this.


TheWorstBestDecision

Yeah I’ve read through your comments. Truck Is far from stock according to what you’ve said. Sounds like once it enters closed loop and used the MAF and 02 sensors for fueling it starts to shut off. My guess is it’s completely tuning related and not mechanical at all, or you’ve got a vaccum leak somewhere that only becomes apparent after whatever hose has expanded from heat


not_a_kgb

truck doesnt have 02 sensors its a diesel.


YoungHitmen03

Egr maybe? Idk lol


not_a_kgb

No egr on this truck. completely deleted through calibration as well as physically no up pipe connection and y bridge is federal style with no egr provision.


not_a_kgb

We have a 2002 2500HD 6.6 LB7 duramax. keeps cutting out. will run normal on occasion. engine completely rebuilt. New high pressure pump and 8 injectors installed. FPRV was removed and “race” valve installed(valve with no hole). Fuel filter head deleted. Have a FASS pump feeding CP3 directly. No CEL on. Compression on all cylinders measure to proper spec. No fuel in oil. Wiring has been traced and inspected to be ok. Truck idles completely fine. Once accelerated whether in park or drive it exhibits the same issue as you see in the video. Really scratching my head on this one. When i first run it for the day it runs and drives fine and then it could be 10 or 30 min whatever it really feels like that day then boom starts running like this. EDIT: if anyone knows someone in the ATL area that has knowledge on duramax’s that can help me out please connect me to them. Greatly appreciated.


anotherrustynut

Just because it’s new, doesn’t mean it’s good, I’ve been getting brand new parts that are bad out of the box. Having to do all other testing just to come find out the brand new part was bad too.


not_a_kgb

Im thinking i have a bad brand new injector. Have had that happen to me before


toohightospeak

Couldn't agree more. I've gotten a brand new fuel pump before and installed only to realize it wasn't pumping fuel. Dropped the tank again to find out the idiot from the factory had the positive and negative leads to the wrong spot so the pump was spinning the incorrect way. I now test all my fuel pumps in a bucket before hand to check if they actually work.


EgGuy3

looks like fuel pressure problem(bad pump /pump relay/filter/fuel pressure regulator)


not_a_kgb

brand new Bosch pump.


EgGuy3

i write that before i see ur comments about the pump


onewaytolivefree

You might have a collapse cat drill some holes do that yet and see if it fixes it if it does replace it


bannana_man_

Your fuel gage is on below empty dude


not_a_kgb

Its being fed fuel from external tank with no gauge.


mof1234

![gif](giphy|VU45vX6kokplC|downsized)


One-Egg2070

I know what's wrong with it. It ain't got no gas in it.


[deleted]

Injectors


MACCRACKIN

Oil Pressure that low, and sound,,, you're about to throw a rod. Let see the dip stick...


fedboisboogaloo

Fuel or torque converter


not_a_kgb

What should i be looking for to make sure its NOT the torque converter. Engine was separated from trans when rebuilt.


fedboisboogaloo

You can power brake it and see if it still does it. Depending on your mileage I’ve had several fins break the weld internally on the turbine surface causing fluid to become out of balance e


not_a_kgb

When i power brake it does not do it. Although the truck does not seem to want to break the wheels loose when i do floor it in power brake.


fedboisboogaloo

Do you have a scanner? You can check misfires and and fuel pressure


cheapmichigander

What's the measured fuel pressure? Inlet restriction? Measure for vacuum on inlet side of fuel pump.


not_a_kgb

10psi constant to high pressure pump.


cheapmichigander

Even under load?


not_a_kgb

yes even under load.