LBZ: High Rail Pressure at Idle

[heathgu]

Hello Everyone,

I have a Customers Truck which has high rail pressure at Idle, Sounds really bad. I shut it down straight away. First time it has been left over night so i could diagnose the problem.

Seems ok when its hot or when been driven. I only ever see it when it hot, so had no idea it was bad when cold. Only a knocking concern from the owner.

So i put the Tech 2 on it and Rail is at 103mpa at idle. Just off idle it comes back to following commanded. Any idea were to start looking.

It is a 2006 LBZ, ATP tuning, 100gph lift pump set a 8psi, Everything else is stock for the engine.

THANKS Heaps.

Heath

 

[GMC_2002_Dmax]

If it is tuned then start with the tuning, try and put it back to stock to rule that out, my LBZ will tolerate 12 psi from my AD-165 at idle and doesn't cause any fuel pressure issues.

If returning the tuning to stock fixes it you know that needs to be fixed, if it's not the tuning try pulling the lift pump fuse and see if that fixes it, but 103 MPA is pretty high and the fact that it goes away when it warms up leads me to believe a fuel pressure add-on table based off ECT might be causing the issue.

Get back to us when you return it to stock.

 

[heathgu]

Returned it to Stock Tune made no difference.

Disconnected the Lift pump, Staight back to Normal. Dont have a guage to check it but the internal regulator must be getting weak and upping the pressure.

Thanks for the Help.

I appreciate it.

Cheers Heath