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No start no rail pressure

2K views 2 replies 3 participants last post by  Brent@LDS 
#1 ·
Bought an 02’LB7 that Only started with fluid, guy said it just needed a new CP3. Got a new CP3 installed (I am mechanically inclined)it myself, double checked all my lines & fuel fittings made sure everything was good bled the hell out of it but still no start. No rail pressure On scanner. swapped out the fuel rail pressure regulator, blow Out all the lines, still not start. Did a rate return test and didn’t get any fuel, cracked the line to the fuel rail tee and 1&8 inj and got fuel and removed all the glow plugs and turn motor over see inj we’re stuck open but cylinders were dry. Looked through all prior post but didn’t see anything. Any help would be greatly appreciated.
 
#2 ·
A Mystery...

Hello and welcome to the Forum!

As you have learned, relying on advice from the PO can be risky, unless the CP3 was professionally diagnosed, in writing.

“... cracked the line to the fuel rail tee and 1&8 inj and got fuel.”

A visual indication of fuel at the points you noted above says nothing about fuel pressure there but If it is adequate, whatever pressure sensor that is talking to the FICM may be defective or a signal is not getting to the FICM because of a wiring problem.

As you probably know, the Fuel Injection Control Module (FICM) will not wake up and fire injectors until it is informed of around 5000# of rail pressure. I’m not sure where the FICM gets that signal, but should be easy to learn.

Can’t recall where you can tap an injector firing signal. Relatively high “fire” volts that drops down to “hold” volts I believe.

Or, all is well up to the FICM and injectors are not firing because it is defective. Good move on pulling glow plugs to check there. If GP’s are still out, R&R of those inexpensive items would be a smart move.

Some things to consider and I’m sure others will weigh in.

Keep us posted.
 
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