Some help with a fuel problem

[max57]

Have a Airdog pulling from sump, Guage on Tee on Pressure side ( reads 5psi WOT, 10Psi Idling) where it splits to Valley pump Original(120k miles) and new ATS Dual belt driven pump. I see no air bubbles in the return from the two pumps, Changed the fuel Regulator on Original pump and new Fuel Pressure sensor.Had a second ATS Control box so swapped it out. . Injectors are new Lincoln 60%, Balance rates all below -2 at hot idle. Most of the time -1. I tryed raising the feed pressure 14 and does not help.
I am not getting desired pressure wide open throttle , goes above and below commanded 26,250 , mostly below and engine seems to surge or flutter at 3/4 throttle sometimes also. Rail pressure seems to jump up and down. Has a Race tune in it. 800-900hp. s366 with s480. I have a EFI data log if anyone could take a look or any Ideas where to test from here would be great.

 

[ZeroGravity58]

How far below commanded pressure are you talking about? The actual fuel pressure is going to fluctuate. If your commanding 26k but only holding 22k then you may have a weak cp3 in the valley. Personally unless you need a serious amount of fuel id stick to a single valley cp3. I've ran both and the dual cp3s were always more of a headache

 

[Bdsankey]

Have a Airdog pulling from sump, Guage on Tee on Pressure side ( reads 5psi WOT, 10Psi Idling) where it splits to Valley pump Original(120k miles) and new ATS Dual belt driven pump. I see no air bubbles in the return from the two pumps, Changed the fuel Regulator on Original pump and new Fuel Pressure sensor.Had a second ATS Control box so swapped it out. . Injectors are new Lincoln 60%, Balance rates all below -2 at hot idle. Most of the time -1. I tryed raising the feed pressure 14 and does not help.
I am not getting desired pressure wide open throttle , goes above and below commanded 26,250 , mostly below and engine seems to surge or flutter at 3/4 throttle sometimes also. Rail pressure seems to jump up and down. Has a Race tune in it. 800-900hp. s366 with s480. I have a EFI data log if anyone could take a look or any Ideas where to test from here would be great.

What year is the truck? Are both CP3 the same generation? An LB7 regulator is different than a LLY and then again different from a LBZ/LMM. Can you post your log? If it is just bouncing around/not staying consistent that can be a problem with tuning or the dual pump controller. If it is dropping down a bunch then your pumps aren't keeping up.

How far below commanded pressure are you talking about? The actual fuel pressure is going to fluctuate. If your commanding 26k but only holding 22k then you may have a weak cp3 in the valley. Personally unless you need a serious amount of fuel id stick to a single valley cp3. I've ran both and the dual cp3s were always more of a headache

^^

My 14mm in the valley was awesome to deal with. I added a second stock LBZ pump with a PPE controller and so far so good. It hasn't given me any issues.

 

[max57]

it a 2006 LBZ. Dual setup was for LBZ also from ATS. If the valley pump is weak, the second pump should make up. right? I Converted to a zip file , is that good?

 

[2004LB7]

I ran an LBZ cp3 & regulator and my stock LB7 CP3 on my 04. Only hard part was getting the idle down pressure to settle quickly. Getting it to match commanded, other then the previously mentioned issue, was quite easy

Did the tuning myself

 

[max57]

Actual and Desired flow pretty close til 100% throttle then I get 26250 desire but actual floats up and down 21,000psi to 27,200psi. Guess I should check the Fuel rail valve again even though i swapped it out with a new one . any other suggestions, or tests

 

[Don@F1]

Can you raise the low pressure feed to the CP3s up to 12psi at WOT?

I see you already tried 14psi. Scratch that idea above.

What is your duration on big tune?

 

[max57]

Heres a screen shot

 

[Don@F1]

I dont see the duration on that pic above.

Almost always when the pressure goes up and down or surges like that, it is an FCA, MPROP, pressure control actuator (as they are often called) Tuning around it is one fix, or borrow a stock part for that year and see if it resolves

 

[max57]

I dont see the duration on that pic above.

Almost always when the pressure goes up and down or surges like that, it is an FCA, MPROP, pressure control actuator (as they are often called) Tuning around it is one fix, or borrow a stock part for that year and see if it resolves

What do you mean Duration of tune? It is a Rob Codden Race tune. I put a new fca on valley pump as it was original (2006), Made no affect. The second pump is ATS twin pump has only 1000 miles on it but I could try my old FCA for a run. I need to double check the Rail Releif as well. Thanks Don

 

[Bdsankey]

What do you mean Duration of tune? It is a Rob Codden Race tune. I put a new fca on valley pump as it was original (2006), Made no affect. The second pump is ATS twin pump has only 1000 miles on it but I could try my old FCA for a run. I need to double check the Rail Releif as well. Thanks Don

Duration is the total time that the injector is open to inject fuel. It is called "MAIN INJECTION COMMAND" in a data log and measured in microseconds (uS).


It looks like your pumps are having a hard time keeping up OR the relief valve is popping since 0% is the pumps running wide open and its oscillating pressure. That said, Rob isn't tuning anymore so you would need to get a retune from someone else. I'll take a look and see if your log is watching the mA applied to the reg to see if it actually is going to full flow.

 

[max57]

I shimmed the Rail valve and get improvement WOT. So definitely leaking by, I logged it again and held it at 45% throttle and still getting surging, Desired and Actual going up and down , 19,000 to 21,000. WOT it ran a lot better but still a little drop in pressure once in a while. What could the surging at part throttle be?
I do not see a PID available for "MAIN INJECTION COMMAND. I am not the best with EFI live. I do have FRPCOM which reads from 48%(Idle) to 0% (WOT) . I do not see below 13% at WOT, Every once in a while a spike to 5% . (think it is rail releif opening maybe)
I will shim the rail valve a lot tighter and try that. I can not put Race Plug in as ATS has a banjo fitting on the end of it with a TEE FOR PUMP AND INJECTOR RETURNS. I see they have a newer block which allows the R plug.

 

[Bdsankey]

I shimmed the Rail valve and get improvement WOT. So definitely leaking by, I logged it again and held it at 45% throttle and still getting surging, Desired and Actual going up and down , 19,000 to 21,000. WOT it ran a lot better but still a little drop in pressure once in a while. What could the surging at part throttle be?
I do not see a PID available for "MAIN INJECTION COMMAND. I am not the best with EFI live. I do have FRPCOM which reads from 48%(Idle) to 0% (WOT) . I do not see below 13% at WOT, Every once in a while a spike to 5% . (think it is rail releif opening maybe)
I will shim the rail valve a lot tighter and try that. I can not put Race Plug in as ATS has a banjo fitting on the end of it with a TEE FOR PUMP AND INJECTOR RETURNS. I see they have a newer block which allows the R plug.

Have you done a bottle test yet to see if it is the relief valve popping?

 

[max57]

Definitely popping! No, It has this silly ATS block with all the returns hooked by a banjo on the end of relief so real pain to test it. I flipped the adjuster so bottomed the spring on the Rail Relief (As Race Plug) and seems to be good. I will have to do a log when my computer charges up. Let you know soon. Thanks

 

[max57]

https://youtu.be/6TLH92ysEkU . As you can see from 40% -100% throttle it commands 26,250psi but actual 23,000psi to 28000Psi in a rithum up & down. it does run better after i put a bolt in the relief instead of the spring so no relief.