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View Full Version : 6.7L rail pressure sensor in a 5.9?



skneeland
August 9th, 2011, 12:03 PM
I have been told that the rail pressure sensor from a 6.7L has the same thread pattern & electrical connection as the ones in the 5.9?
Anyone able to validate this? Also wondering if anyone has upgraded & respanned their 5.9 with this mod?

my truck goes through a sensor at least every 6 months (its gotta be the diprocol rail pressure gauge.....) at $450/sensor from the dealer im getting a little fed up of this. It looks like I have another one going now & I was thinking of trying this mod....

*yes, i have seen replacement sensors online for under $100, but of course they seem to go at the worst time when im in the middle of nowhere*

AH64ID
August 9th, 2011, 12:28 PM
I understand that the connector is slightly different, but can be easily modified to work.. A 6.7 rail pressure gauge would be needed, but the ISSPRO one works on both connectors so no modification would be necessary.

IIRC you would run approx 13% higher rail pressure unless you re-map the sensor voltage.

FUBAR
August 9th, 2011, 10:11 PM
Excuse my ignorance.. But is the 6.7 sensor more robust or ??

2007 5.9
August 9th, 2011, 11:41 PM
Excuse my ignorance.. But is the 6.7 sensor more robust or ??

There is a thought that the 6.7 sensor is a 30K sensor from the factory...

~Les

DoghouseDiesel
August 10th, 2011, 12:31 AM
Just be careful if you use it.

Just because the sensor can read higher, doesn't mean your fuel system can handle the higher pressures.....especially if you have the old style injectors in the early '06's.

Start pushing 28K psi and you're gonna do damage.

If you have the newer style stainless steel injectors and are using the larger 6.7 connector tubes, rail and lines, it's a little more forgiving, but just changing the sensor so you can see the higher pressures is like putting a depth finder on a boat and running in shallow water....by the time you see something, the damage is already done.

AH64ID
August 10th, 2011, 12:49 AM
From some old notes I have the 5.9 sensor has a range of 0-26107 psi and the 6.7 has a range of 0-30000 psi, in the same 0-5v reading.

There are several people running a 6.7 sensor just for the 13% rail pressure increase across the board.

2007 5.9
August 10th, 2011, 01:18 AM
Although I am not a fan of running pressures of over stock, it would be nice to see what my actual pressures are on a spike at the end of a WOT run....seeing 27.5K on the gauge...I know it's getting higher.

~Les


---
I am here: http://maps.google.com/maps?ll=37.996567,-122.070181

DoghouseDiesel
August 10th, 2011, 01:40 AM
Although I am not a fan of running pressures of over stock,

~Les



Nor am I.

Lot of risk for minimal gain.

Most of the damage I see come in is from a combination of 3 things.....
1 - Mod or Dual CP3's
2 - Relief valve removed or modified
3 - Pressure box; specifically MP8's.

Those 3 right there are the common denominators that I see with injector and piston damage.

Do I run a relief valve? No.
Do I run dual CP3's? Yes.
Do I run RP higher than 24K psi? No.

AH64ID
August 10th, 2011, 01:45 AM
Has anyone noticed how much lower pressure the 6.7's run while cruising? They do go much higher under load, but are considerably lower at low load... maybe Dodge/Cummins realized the gain wasn't worth it and dropped the average pressure to get longer life?

DoghouseDiesel
August 10th, 2011, 02:05 AM
That may also be due to the emissions requirements, which is more than likely the bigger issue.

AH64ID
August 10th, 2011, 02:21 AM
I thought that lower pressure led to worse emissions? Thou maybe not..

DoghouseDiesel
August 10th, 2011, 02:29 AM
Not necessarily.

Lower pressure with large nozzles doesn't give good atomization and that's not good.

But, lower pressure also pushes less fuel over the duration period.

As long as the pressure is high enough for good atomization, having it a little lower won't hurt emissions.

Who knows....looking at some of the OEM maps makes you wonder what the heck they were thinking in the first place.

AH64ID
August 10th, 2011, 02:32 AM
Who knows....looking at some of the OEM maps makes you wonder what the heck they were thinking in the first place.

That's the truth! Some of the stuff is just amazing.

johhnyfoxtrot
August 10th, 2011, 03:15 PM
I agree and disagree with some if this so far. I have a new sensor can get a part number later. My dual mount broke and took the senspr with it so I called and there are three aleast part numbers for sensors. I opted for the newest one that is also good back to the 03 model year per serial number on my engine. I paid 123 for it from the Cummins dealer down the road. Just becausee it will run/read a higher pressure don;t mean the electronics will put pressure there. I have an ISSPRO rail guage and the most I have seen out of it was 30K once and my truck will pick up 4 mph and nearly half second in the 1/4 by going from 21K to 25K psi rail. Went from a 12.2 to 11.7et and 114 to 118mph in just 4K psi.

skneeland
August 10th, 2011, 04:34 PM
Excuse my ignorance.. But is the 6.7 sensor more robust or ??

I have heard rumors of such. i also would respan the input so the ecm would still see actual pressures. my in dash gauge would be off, but the the difference could easily be taken into consideration. I run 26k max r.p. which is right at the end of the stock 5.9 sensor range, so you can see how a 30k gauge would be handy

comnrailpwr
August 10th, 2011, 09:37 PM
Why not just remap the original sensor? Looking at the tables it appears easily done. Basically saying x voltage = higher MPa.

Spray & Pray

DoghouseDiesel
August 10th, 2011, 10:29 PM
Why not just remap the original sensor? Looking at the tables it appears easily done. Basically saying x voltage = higher MPa.

Spray & Pray

It's not that easy.

Let's say, for example, you have a 3 bar sensor. It's calibrated for approx 45 psi. That's as high as it can read.

Just rescaling it to 60 psi, won't make it actually read 60 psi. At 45 psi, the diapraghm or spring is fully compressed and by recaling it to read 60 psi, all you're doing is telling the ECM that you're at 60 psi, when in fact you're at 45 psi.

Rescaling only works if the sensor can actually read the pressure you're asking for.

The other thing this does is throws off your analog gauges and what it sees in the log files.

Your analog gauge (true reading) would be showing 45 psi and your log file would be showing 60.

Makes it much harder to correlate what's going on with what needs to be fixed.

comnrailpwr
August 10th, 2011, 11:19 PM
Ahh that makes sense. I wasn't sure. So basically with the ecm sensor tables should be left just the way they are.

Spray & Pray

skneeland
August 16th, 2011, 03:47 AM
anyone happen to have cummins part numbers for both sensors?
i refuse to pay $450 from the dealership, i know i can get them for $99 online....

6cummins
September 14th, 2011, 03:28 PM
anymore update on this? Just swap them out and good to go?

skneeland
September 14th, 2011, 11:47 PM
anymore update on this? Just swap them out and good to go?

i ended up buying a 5.9sensor from a Bosch dealer for $180, nobody had a 6.7 sensor in stock anywhere near me.
Next time im going to buy the whole 6.7 rail, I can buy the whole rail including relief valve & sensor for $360.....

6cummins
September 15th, 2011, 04:35 AM
Just curious if anyone can verify for sure there is a 13% increase across the board..