2003 duramax lb7 p0089 help

[pat5001]

I got a 03 dmax lb7.with code p0089. The des fuel press is 40mpa and starts climbing to 160mpa and stays there. Also had fuel dilution problem. So I did all 8 injectors, fuel filter, fpr in cp3.
Still act fuel press is 160mpa.
Also what should the fpr voltage be?

 

[Bonestock]

Sounds like a bad regulator.

 

[pat5001]

A bad new regulator?

 

[chevyburnout1]

Does the engine idle like the fuel pressure is ramped up? Kind of knocky/rattly? Or does it just say the pressure is high?

 

[07keo02]

Was the high fuel pressure a problem before the Cp3 replacement? If not, did you verify the Regulator was plugged in on the back of the Cp3, if not it will max out.

 

[pat5001]

Yea the motor /injectors make a lotta noise just like its got high pressure. The problem has been there since the start. It's plugged in its also got a newer connector

 

[Evan@InglewoodTrans]

Did you check the wires going to the FPR? Sounds like you could have a issue with them.

 

[pat5001]

What should purple/white wire be at fpr connector key on unplugged and key on plugged in? Also what should it be running at idle?
And is the yellow wire the ground/signal?

 

[pat5001]

Anyone? What's key on voltage purple/white wire. And what kind of signal ECM send yellow wire? It's like the fuel pump runs maxed out.

 

[chevyburnout1]

The purple/white is the supply voltage and the yellow is the control side. However I couldn't tell you what the voltages should be. With everything plugged in and the engine running the only code it still sets is the P0089 code?

 

[pat5001]

Yea just p0089. It says 1.94 volts plugged in. On another truck I had 2.38 volts.
I also had 6.88 volts with it in plugged. Another truck had 8.78.
Should it be 12v ??

 

[chevyburnout1]

There's no specifications for voltages for the FPR circuit that I know of.

 

[pat5001]

Fixed p0089

Fixed p0089.
Fixed the duramax it was a bad computer

 

[Tunamaxx]

Fixed p0089

Fixed p0089.
Fixed the duramax it was a bad computer

How did you figure out it was a bad computer? And what computer the ecm? I have the same code and just replaced my fpr.

 

[2004LB7]

How did you figure out it was a bad computer? And what computer the ecm? I have the same code and just replaced my fpr.

he hasn't been around since 2016 so don't be surprised if he doesn't respond. plus this thread is from 2013

 

[LBZ]

How did you figure out it was a bad computer? And what computer the ecm? I have the same code and just replaced my fpr.

I would guess as the ecm controls the regulator he checked the wiring and found it to be ok and tried a known good/new ecm and it fixed the issue.

 

[Ron Nielson]

The ECM sends the FPR a pulse width modulated signal that controls the pressure. PWM signals need to be viewed with a scope because those pulses happen way too fast and vary in voltage for a DVM to capture the signal in any meaningful way.

 

[N2BRK]

Look for wires rubbed through or cut and shorting.