Fuel Rail Pressure

[Dave Lewis]

I noticed when data logging fuel rail pressure (actual and desired) at certain points the pressure reading jumps from 18000 psi to ~62000. This matches the corresponding desired fuel pressue. If I'm not mistaken the max for the Duramax is around 23000-24000 psi. All of this occurs when accelerating. Anybody have any ideas? It is possible I am doing something incorrectly since I am still learning / playing. This is on a stock tune.

Dave

[Trippin]

I noticed when data logging fuel rail pressure (actual and desired) at certain points the pressure reading jumps from 18000 psi to ~62000. This matches the corresponding desired fuel pressue. If I'm not mistaken the max for the Duramax is around 23000-24000 psi. All of this occurs when accelerating. Anybody have any ideas? It is possible I am doing something incorrectly since I am still learning / playing. This is on a stock tune.

Dave

Any chance it's 6200 instead of 62,000?

[Dave Lewis]

No, not that I can tell. The other values all appear to be correct (18000) but then it jumps when stepping on the pedal. At steady state everything goes back to around 22000-23000 psi. I was going to post a screen capture but I can't get it small enough to upload.

[Trippin]

Would you send me a copy of the log file?

gtripp@earthlink.net

[GMPX]

No, not that I can tell. The other values all appear to be correct (18000) but then it jumps when stepping on the pedal. At steady state everything goes back to around 22000-23000 psi. I was going to post a screen capture but I can't get it small enough to upload.

Dave, use - http://www.irfanview.com/ for capturing screen shots.

I wouldn't mind seeing the logs too.

Cheers,
Ross

[trudynosports]

According to a friend of mine that works at the local big truck shop the duramax fuel rail pressure if you dead head the regulator can reach 80,000 + Psi. Like I said this is from a GM master tech who works on these things every day.

[Dave Lewis]

File sent. Ross I'll try that program in the future, Just something else I have to learn.:eek:

[GMC-2002-Dmax]

Was that the tune I sent you ????

[Dave Lewis]

No. It was my stock tune. I thought it was at first but I re-ran it. That reminds me it is with the Juice at 5/5 though (just bought normal gauges so I can pull the Juice). Not sure if thats where the problem is. Sorry for leaving that "small" piece of info out.

[GMPX]

That reminds me it is with the Juice at 5/5 though (just bought normal gauges so I can pull the Juice).

:eek: stackers need not apply :hihi:

I must confess I don't know enough about how the Edge 'modifies' the sensor data to/from the ECM, wait until it is gone before we look too close at log files.

Cheers,
Ross

[DURAtotheMAX]

Yeah my fuel rail pressure reads all wrong too. Sometimes it jumps up to 70,000 PSI or so....but thats on an LLY dmax.

[GMPX]

Can you guys please switch it over to show MPa, not PSI.
Should show between 30 - 160 Mpa.

Cheers,
Ross

[Trippin]

Just played the log file on my laptop:

Scan build 312
dll 454

And everything looks good in Imperial. Perhaps the latest revision reverted back to what we saw during LB7 Beta?

[GMPX]

Looking at the log file I see between 30Mpa and 140Mpa which is quite normal. Looking at that in PSI it shows between 17,000PSI and 64,000PSI.

Is that what you guys are seeing?.

Cheers,
Ross

[DURAtotheMAX]

yes. Thats what I see on my LLY. Strangley tho, the "fuel rail pressure" reads correctly in PSI. Its only the "actual rail pressure" and "desired rail pressure" that read wierd.

[Trippin]

yes. Thats what I see on my LLY. Strangley tho, the "fuel rail pressure" reads correctly in PSI. Its only the "actual rail pressure" and "desired rail pressure" that read wierd.

Looks OK in PID "SAE.FRP_C"

But PIDs "GM.FRPDES" and "GM.FRPACT" are incorrect.

[Dave Lewis]

That's what I'm seeing.

[GMPX]

Looks OK in PID "SAE.FRP_C"

But PIDs "GM.FRPDES" and "GM.FRPACT" are incorrect.

Just when viewing PSI or in MPa too?........c'mon guys, now's the time to go metric :hihi: :joke:

Cheers,
Ross

[Dave Lewis]

Didn't check yet, I was having a sleepless night. Will do it in the morning. I went through engineering school using metric but as soon as I got out in the "real" world everybody was using Imperial. I prefer metric just not used to it anymore.

[GMPX]

Didn't check yet, I was having a sleepless night. Will do it in the morning. I went through engineering school using metric but as soon as I got out in the "real" world everybody was using Imperial. I prefer metric just not used to it anymore.

Cool, one down, 300,000,000 to go :joke:

Cheers,
Ross

[trudynosports]

Wish we would have gone metric a long time ago, like back when I was in college. It's a lot easier than Imperical!

[Dave Lewis]

Works fine in metric.

[Kennedy Diesel]

There can be some WIERD stuff logged as peak values. Not sure if it is an Edge issue or not, but I know that they stopped recording things (in "records") like max EGT and Boost due to erroneous spikes to what would seem like about 4x normal...

[GMPX]

Again, I'm not sure exactly what signals the Edge intercepts, but Desired Pressure should not fault, Actual may get 'altered'.

Cheers,
Ross

[Dave Lewis]

I'll get my new gauges on and retry it.

[sweetdiesel]

Yeah my fuel rail pressure reads all wrong too. Sometimes it jumps up to 70,000 PSI or so....but thats on an LLY dmax.

70000 psi is like 482mpa why so high i geuss when i thought a couple mpa was lots but now.....wow:master: