Green_Machine

Hi all.

My truck will run very well at any rpm, but when I load it up, over 20psi or so, it falls flat on it's face like someone turned off a switch.

Seems like I'm looking for something that is causing a defuel-like condition. I suspect the cause is something to do with when the rail pressure is high in the operating range.

I have run the 10 second test for the lift pump. It did not meet the 430ml volume requirement.

I changed the filter and now it's at 450ml. Should be good enough.

I removed and cleaned (By disassembly) the FCA. It seems to be in good condition. The sleeve is free. The pin slides well.

I removed and tapped a 1/8npt into the fuel rail relief valve banjo bolt, blocking the exit of the valve. No change

I used my code reader (It has rudimentary live data recording) to check the tps. It stays at 100% after the power drops off. The tool does not show me commanded or measure rail pressure. Sucks!

No codes either btw, no MIL, no nothing!

Next up is to check injector returns and CP3 return. Also swap the rail pressure sensor to see if there's any change.

Any ideas??

I'm uploading a video of how it acts as I type. I will add it to the thread when it's done.

Thanks for any advice.



***Here's the you tube video:



Chay

Green_Machine

One more clue possibly...I reviewed the live data log again and when the truck falls flat the map is recording 40kPA. This means it's drawing a vacuum...then it recovers to 100kPA (Atmospheric).

Is this typical? Perhaps it indicates a blockage in the intake tract like a turbo stopping spinning or something? Maybe the puff of blue is oil from the turbo seal dying when the turbo stops?

Gotta check the turbo now.

Chay

Green_Machine

A breakthrough of sorts.

I removed the intake piping from the air cleaner to the turbo intake in order to video the compressor with a go-pro like camera. I removed the intake sensor from the intake pipe and plugged it into the harness allowing me to run the truck without setting codes.

I checked the turbo...a touch of radial play and a touch of axial play. Feels like a couple of thou. Rotates freely.

Spins and created positive pressure at idle.

Here's the kicker:

I cannot get the truck's symptoms to repeat with the pipe off.

I am now looking at either:

1) Small amounts of vacuum between the air filter and the turbo causing the turbo to have issues at high boost (Friction/stalling the shaft, creating a restriction).

2) Some type of intermittent blockage in the air filter chamber/intake pipe

Cool eh?

Chay

Green_Machine

Ok found the issue.

Kind of a doh moment.

A few months ago my passenger side fender liner had half failed. I didn't have time to fix it properly so I removed it to prevent it from becoming broken up further.


Because of this, the wheel filled the bottom portion of the air cleaner box with fine sand/gravel.


I should note that my airbox has never had the suction guage, that hole is plugged.

Anyway, when the demand got high enough the sand flew up into the air filter, plugging it and killing my truck. Off the power, the sand falls again.

Dumb. Easy fix anyway. Think I'll bring the air in from the front instead of from the fender!

Chay