LB7 30 over tips/ fuel delivery

[DuallyLB7]

Hi guys,

Had the truck scene new a 2001 LB7 dually. Just did the injectors on it, the originals held for 160,000 miles!

I lost an injector with the typical white smoke and un intentional "loop tune" at idle.

Before the swap she could tow anything up any grade under any conditions, best running truck ever, however... I swapped out all 8 injector tips with 30 "over" ones. she was running fine for a month, I didn't tow anything with the new tips in... yet. I did a series of trips picking up some project cars "not the heaviest thing I've towed by any means".

Went into safe mode "fuel leak" when loaded up/ spooling going up some steep long hills. She would slow down as usual and id pull over and clear the code and coast home...

Its not a fuel leak on the block, I replaced the fuel lines running to the fuel computer along with a few other lines running ontop of the engine.


Am I not delivering enough fuel to the new 30 over injectors when spooling with heavy loads?????

 

[DAVe3283]

Have you checked for diesel in the oil? If an injector is leaking fuel, you won't usually see it outside the motor. It will either return excessive amounts (this is the good option), or leak into the oil (this is the bad option). If you don't have diesel in the oil, you might still have one or more injectors returning excessive amounts of fuel and causing the code.

Also, to be clear, you took the failed 160k mile injectors, and swapped new +30% tips onto the old worn bodies?

 

[OregonDMAX]

Assuming you didnt just throw on 30% over tips on the 160k mile injectors. Did you have the tuning adjusted to compensate for the 30% over tips.

 

[DuallyLB7]

Everything is stock besides the 30 over tips. when I installed them I was concerned about the fuel delivery, I hope that the 30 over injectors are causing the problem.

I have NOT touched any tunes or any other adjustments to the fuel other than the tips.

Am I correct on the fact that i need to increase fuel delivery?

Everything else on the truck is fine, no fuel in the oil or anything like that.

What tuner/ adjustments can be done to satisfy the new tips?

 

[hondarider552]

So did you or did you not replace the original injector bodies.

 

[THEFERMANATOR]

Like said above, if you just did tips then you created issues. Teh tips is not what leaks over time, it is the ball seat that wears out and causes high fuel return. And as far as tuning goes, you need to have the pulsewidth REDUCED in the idle areas to compensate for the oversized injectors. Some go without compensating and are fine, and other trucks will bellow smoke and not run for crap(who's injectors are used has a big role in this area, you get what you pay for).

 

[DuallyLB7]

The electronic solenoid on the injectors are still stock “aka 160,000” miles on them.

I replaced the 8 original tips with 30 over tips.

Nothing else

Didn't touch any electronics or fuel delivery adjustments.

So its a stock truck with 30 over tips...literally.

I was worried about the "solenoid Ball" leaking, however i already had issues, white smoke ect... The new tips solved the problem, its only when towing it goes into safe mode "excessive fuel leak" code. I was thinking along the lines of a "lack of fuel".

So turn up the fuel delivery and reduce pulse width at idle?

 

[yellowchevy]

The electronic solenoid on the injectors are still stock “aka 160,000” miles on them.

I replaced the 8 original tips with 30 over tips.

Nothing else

Didn't touch any electronics or fuel delivery adjustments.

So its a stock truck with 30 over tips...literally.

I was worried about the "solenoid Ball" leaking, however i already had issues, white smoke ect... The new tips solved the problem, its only when towing it goes into safe mode "excessive fuel leak" code. I was thinking along the lines of a "lack of fuel".

So turn up the fuel delivery and reduce pulse width at idle?

Just to clarify, you pulled your stock 160k injectors, put new 30% over tips on them, then reinstalled them?

If so, you need new injectors.

Yellowchevy

 

[DAVe3283]

By the time LB7 injectors are smoking/loping, the ball seat inside the injector body is worn out. It would also be common for the tips to be in bad shape.

By putting on new tips, you improved atomization of fuel, which fixed the smoke/lope. But the ball/seat is still worn, and that is where the fuel is leaking. It then returns through the return system (excessively), and is what is causing the truck to think there is a fuel leak.

To fix this, you are going to have to replace the injector bodies. If you like to live dangerously, you can play with the tune to either trick the computer into thinking there is not excessive return fuel, or just disable the limp mode. Hopefully your bodies hold up, and don't eventually split, dumping a ton of fuel right into your oil. But really, you need new injectors. No easy way out.

 

[clrussell]

No comment, I'm out...


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[WolfLMM]

You needed new injectors, not just new tips. And anytime you change nozzle size, it requires a retune. You are changing the injector flow rate, how do you expect the ecm to accurately deliver a quantity of fuel, when you are deceiving the ecm.

 

[DuallyLB7]

I was concerned with the injector solenoids being shot, however I was "persuaded" to only do the tips. Ill probably swap out the solenoid, the truck is too nice to start jerryrigging.

We all have to learn some how!
This will be a good time/ excuse to find something else to upgrade...

Thanks guys, ill keep the pedal off the floor and no towing until I open her up again.

Luckily its not boating season yet, wont stress her with 12k of boat to haul.

Thanks everyone

 

[OregonDMAX]

I was concerned with the injector solenoids being shot, however I was "persuaded" to only do the tips. Ill probably swap out the solenoid, the truck is too nice to start jerryrigging.

No, don't change the soleniods, By just swapping out the solenoids you will be jerryrigging it.
YOU NEED INJECTORS.

 

[Chevy1925]

you need to buy the whole injector and either swap your tips over or run the stock tips. if you liked the way it ran before, put the stock tipped injectors in and go.

YOU MUST REPLACE THE WHOLE INJECTOR. we are all under the impression you are only going to replace parts of the injector, you can not fix the problem areas of the injector by doing this. the only option is to replace the whole thing and swap tips or run the stock tips.

 

[Duramax One]

YOU MUST REPLACE THE WHOLE INJECTOR.

This

 

[THEFERMANATOR]

By the time LB7 injectors are smoking/loping, the ball seat inside the injector body is worn out. It would also be common for the tips to be in bad shape.

By putting on new tips, you improved atomization of fuel, which fixed the smoke/lope. But the ball/seat is still worn, and that is where the fuel is leaking. It then returns through the return system (excessively), and is what is causing the truck to think there is a fuel leak.

To fix this, you are going to have to replace the injector bodies. If you like to live dangerously, you can play with the tune to either trick the computer into thinking there is not excessive return fuel, or just disable the limp mode. Hopefully your bodies hold up, and don't eventually split, dumping a ton of fuel right into your oil. But really, you need new injectors. No easy way out.

The other part your forgetting is if excess fuel returns to the tank, this can also cause the inejctors to open. The injector is a pressure differential valve, it opens by the solenoid opening the bypass which causes an internal pressure drop inside the inejctor, and the injector opens. So if a ball seat is worn badly enough, it can bypass enough fuel to cause an injector to open on it's own without being triggerred to. Most hung injectors are because to much fuel is bypassing the ball seat which causes the injector to go open without being triggerred.

 

[hondarider552]

Wow.

 

[Yngdmax92]

I am thinking you are the fella that posted the video on youtube about changing injectors? stated it was cheap and only cost you 600 dollars or so to change them? I am not busting your chops by no means but when i watched that video and saw that you did not change the whole injector....wow is just what i thought. Get ahold of Lincoln diesel and get some reman injectors

 

[TheBac]

Wow.

Thats what we're getting nowadays, Bri.

Solenoids on these injectors arent the problem, O/P. Its the ball/seat inside the injector body...which is something an everyday person CANNOT repair.

You probably flushed debris into the injectors when you undid the high pressure lines, and now that crap finally wore the injectors out. 160,000 is impressive for a set of LB7s, esp an 01. Lincoln Diesel has an excellent rep with LB7 owners.

 

[Awenta]

Or exergy. Please don't go off trying to save a few bucks and having to do this a third time.

And you need to get tuning to compensate for the change in amount of fuel sprayed. No way around that.

If you have a stock truck and it's staying stock then leave the stock injectors. You gain nothing by going to bigger injectors. Stock can push well beyond what your transmission can hold.

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