Diagnosing with dual pumps

sootie · Jul 17, 2016

Have you changed tunes at all?

6.4 Stroker · Jul 17, 2016

Groomzybanshee said:
If you give it more throttle will it come out of it?

With dual pumpes installed it would pull out with more throttle, but with a single pump it wont.

6.4 Stroker · Jul 17, 2016

sootie said:
Have you changed tunes at all?

Tried going back to canned H&S tunes with no luck

Jonnydime · Jul 18, 2016

So even with a single pump and stock injectors it still does it? Is it bypassing inside the pump or returning out the injectors through the heads?

footlong70 · Jul 18, 2016

Has the pump been reversed on the front mounted pump?

6.4 Stroker · Jul 18, 2016

Jonnydime said:
So even with a single pump and stock injectors it still does it? Is it bypassing inside the pump or returning out the injectors through the heads?

It's basically back to stock fuel with a lift pump now.
I don't think is bypassing, but I don't know for sure.
Basically I start the truck and it idols absolutely perfect. Then for whatever reason when I get around 10k rail pressure, pulsewidth maxes out at 3.0 rail drops to 1.5k and the truck bearly runs. But as soon as I let off the throttle its as if there's no problem.

6.4 Stroker · Jul 19, 2016

footlong70 said:
Has the pump been reversed on the front mounted pump?

Sure has. I drove it with dual fuelers for about 2 years with zero problems.
I returned the truck to stock fuel trying to run the program down.

6.4 Stroker · Jul 19, 2016

Just a recap. The truck is back to stock fuel,
with a new rail pressure sensor, hpfp gasket/harness.
Also has a hpfp, and injectors pulled from a running truck.

6.4 Stroker · Jul 19, 2016

I think if I could figure out why PW is maxing out I could find the problem.
So right now I'm thinking I got 3 potential problems.
1 a bad engine harness?
2 a bad sensor somehow causing pw to skyrocket?
3 a bad computer?

madman1234509 · Jul 19, 2016

Have you changed the pump harness and any wiring that may control the pump?

I guess my next question would be what sensors are utilized to increase PW, that may be freaking out?

Groomzybanshee · Jul 19, 2016

6.4 Stroker said:
Just a recap. The truck is back to stock fuel,
with a new rail pressure sensor, hpfp gasket/harness.
Also has a hpfp, and injectors pulled from a running truck.

Did you try new under vc harness on rail sensor side?

6.4 Stroker · Jul 19, 2016

Groomzybanshee said:
Did you try new under vc harness on rail sensor side?

Not yet I'll get one coming.

6.4 Stroker · Jul 19, 2016

madman1234509 said:
Have you changed the pump harness and any wiring that may control the pump?

I guess my next question would be what sensors are utilized to increase PW, that may be freaking out?

Yup pump harness, and pump gasket are new.
Still need to try a new under valve cover gasket on the passenger side. Also might try my buddy's spare main engine harness.
As far as sensors effecting PW I'm not sure witch would.

6.0 Tech · Jul 19, 2016

Crazy out in left field thought, but figure id throw it out there as the uvc harness has been recommended, but are your ebp and map sensors reading roght? Could be it starys to dump fuel trying to increase ebp or map. Also, does low pressure stay steady? Maybe somethin floating in the tank and plugs the pick up, or a kinked line or something, rsstricting flow either to the low pressure pump or to the hi pressure pump...

6.4 Stroker · Jul 20, 2016

6.0 Tech said:
Crazy out in left field thought, but figure id throw it out there as the uvc harness has been recommended, but are your ebp and map sensors reading roght? Could be it starys to dump fuel trying to increase ebp or map. Also, does low pressure stay steady? Maybe somethin floating in the tank and plugs the pick up, or a kinked line or something, rsstricting flow either to the low pressure pump or to the hi pressure pump...

Thinks for the input.
Backpressure doesn't stay as consistent at I think it should so I'll check that out. Hopefully something will turn up.
Picked this up too.

6.4 Stroker · Jul 21, 2016

No luck yet, but I did manage to get a vid.
Shows exactly what I'm dealing with.
Truck is running without turbos is why it sounds so... awsome!
https://youtu.be/9kIXAayUZlc

Groomzybanshee · Jul 21, 2016

6.4 Stroker said:
No luck yet, but I did manage to get a vid.
Shows exactly what I'm dealing with.
Truck is running without turbos is why it sounds so... awsome!
https://youtu.be/9kIXAayUZlc

Same damm thing mines doing.

6.4 Stroker · Jul 21, 2016

Thats Crazy.
I'm gonna go after the actual engine harness next.
Gonna figure it out one way or another.

bigrpowr · Jul 21, 2016

6.4 Stroker said:
Thats Crazy.
I'm gonna go after the actual engine harness next.
Gonna figure it out one way or another.

i feel your pain homey . i chased a really random starting issue recently .. my truck would f'ing start prolly 1 out of 50 attempts . starter passed, everything passed. i swapped the shifter, adjusted the linkage on trans, chased everything. at a glance i said , F it , ill swap the starter for giggles , even though when it turned it was perfect every time. pulled starter , and a stud was loose . i know its not the same thing , but it was a huge pita . damn electronics i tell you .