Fuel Rail High Pressure Sensor Upgrade
 

Some History:

Cobb recently released the ability to change the targeted fuel pressure in the ECU.
Silverdemon and PTP are both working on upgraded fuel rail pressure relief valves which will allow us to run higher pressures with out hitting the stock valve which opens at ~1875 psi

The problem now is the stock high pressure fuel sensor maxes out at ~140 BAR or 2030 psi. So if your fuel pressure goes higher than this, the ECU cannot correctly measure fuel pressure which it uses to calculate the proper injector duty cycle, causing it to run super rich.

I did some looking around on our forum and someone pointed out an identical sensor that reads 250 BAR but it uses a different connector though other than that it is physically the same. I made some calls and a complete plug and play adapter harness can be made so the upgraded sensor can be used without hacking into the stock wiring harness!

All we need now is the ability to rescale for the higher reading sensor via reflashing the ECU (Cobb Accessport) or piggyback (CP-e Standback).

Stock 140 BAR Sensor Bosch Part Number: 0261545006
Upgraded 250 BAR Sensor Bosch Part Number: 0265005303
I also found out that same upgraded bosch sensor is already used on a Mercedes Benz vehicle with the part number of 0025400917

Attached are the Bosch datasheets in .PDF for both the stock and 250 bar sensors. (REFER TO NEW DRAWINGS BELOW FOR WIRING)

New Information from JumpingJackson
I have been working with BMotorsports, you can now order a preassembled adapter harness from them
http://www.bmotorsports.com/shop/pro...oducts_id/2118


SUPERSKATERS TESTING:


i just purchased my sensor today from here

All European

search for the Mercedes PN or u can use the Bosch PN. make sure you tell them you saw it online to get the $122 price.


i ordered the harness from here. it was free because you can ask to view "samples" of the products.

www.te.com

http://i135.photobucket.com/albums/q...torsupload.jpg



i also found the connector for the stock harness so you can make this 100% PNP. (note the first 3 parts in the list are put together in a "kit" which is what the last item is)

incase you cant see the PN's they are in order:

CONN-11555
CONN-10555
CONN-56057
CONN-75598p


http://i135.photobucket.com/albums/q...sorharness.jpg






HERE IS HOW YOU NEED TO WIRE THIS BECAUSE THE DATA SHEET IS WRONG!!!!!!!

http://i135.photobucket.com/albums/q...ock_sensor.jpg


http://i135.photobucket.com/albums/q...new_sensor.jpg




PNP Harness:

Please note the picture below is not wired correctly because i took it before i figured out the wiring was backwards. If you want to refer to it just swap the position of the yellow and blue wires ON THE SENSOR SIDE OF THE HARNESS

http://i135.photobucket.com/albums/q...829_151800.jpg






INSTALL:


I Also found it is EXTREMELY easy to swap the sensor out when your ready to do this. You dont need to remove anything at all!!!

you will need a deep 24mm (for the new sensor) and deep 27mm (for the stock sensor) socket to get these out. i bought them at pepboys for a total of like 13 bucks. all you need to do is put them on a swivel and there should be plenty of room in there to slip it over the sensor (after you have unclipped the harness of course) and get them out. I did not use thread sealant on the threads because i was swapping sensors so often for testing that i just forgot about it but there is a taper on the end of the sensor which is really whats doing the sealing. Also you only need very little torque to get this thing tight and to seal good. something like 5-10 ft-lbs at MOST.

im in.. how much?

Harness would be 25-50$ for 1 at a time. If we could get a group buy im sure we could get better pricing.
Im not sure how much the sensor is going to be.. I would assume getting it as the Mercedes Benz part would be ass-rape. The same company that would be making the harnesses is checking on the price for the sensor for me as well.

but this item is useless until we get some ecu support from cobb or cpe?

Thats correct, until its supported there is no use for it. (it wont work properly until they can rescale it)

I suspect with a piggyback it could be done fairly easy. Someone with a standback should call CP-e and ask.

In actual operation it would appear that the ECU is capable of reading 2073.9 off of the stock sensor. This is what I was able to log on my car using two different stock sensors (on both the dashsaq and the AP. The AP would only display 2030, but the logs would show 2073.9). I believe SSInstaller indicated that when logging through his SB, he can get readings much higher off the stock sensor (2100+ and he had seen others higher.)

This item is useless until we get a High Pressure Release Valve (which is being working on) since the stock valve opens at 1850psi. Once we have the upgraded unit available then we would need this.

Yes I noted that in my original post.

Also, i sent an email to to Christian @ Cobb. He put in a request to add that functionality to rescale the sensor.

I swear I read everything in the OP, apparently I skipped the third and forth lines haha

Subbed for win.

this is excellent

has anyone done any testing to see how these higher pressures will effect injector longevity?

doesn't anyone work at napa that could buy these for us at a discount?

alternatively, if they are available at like autozone - you can order a few of them and use the ubiquitous 20% off coupons.

what MB vehicle are these used on?

You don't necessarily haaave to have sensor scaling to make it work.. You could just tell the ecu to target much lower pressure with ATR.

i'm feeling a little dense right now, since i haven't driven my car in a week i think i'm losing touch lol...

how is it that on some logs, people have shown fuel pressure spikes of 2100+ psi if the sensor only reads up to ~2030 psi?

Or is this a separate sensor?

this is great

Were those logs from standbacks? Based on SSInstaller's responses in my thread I think the sensor it self is capable of reading higher pressures, but for some reason the ECU is clamped at 2073.9.

The 2030 psi # is probably speculation, dunno where it was chosen from. My guess is it'll read closer to 2100+. Someone could simply put 5 volts on the sensor line and see what # they get on a DH for fuel pressure, and call that the stock sensor limit.

Here's some data points i took a while back:

http://i359.photobucket.com/albums/o...topressure.jpg

As mentioned, 2073.9 as logged on both the AP and DashDaq with two different stock sensors. 2030 is the max the AP will put on its display (and shows it as it top limit on display) but while displaying 2030 it will log values as high as 2073.9. I guess I could try logging to ATR to see if there is a difference. But is it possible the ECU isn't allowing the full range of the sensor as SB users seem to get higher readings?

According to the data sheet, the sensor clamps its output at 4.5V

Link to datasheet?

Post #1 :)

derp derp lol.

Shit this looks easy. Thanks for the leg work Phil.

I'll be ordering one very soon to play with :D



sorry for not reading the op lol. Sometimes i just skim at work cause i'm so fucking busy.

Still curious as to why the SB is able to pull higher pressure readings off of the sensor than the ECU.

its intercepting the signal, not interpreting it from the ecu


amiright?

Maybe the ECU is programmed to limit what it reads. That would make since due to the fact that in an un modded car, it would most likely never see anything higher than that.

Yeah, that is kind of what I was trying to get at. It would seem as if the ECU isn't using the full range as provided by the sensor. Maybe Mazda figured ~10% above the crack pressure of the RV was sufficient to account for in their programming?

http://www.mazdaspeedforum.org/forum/foru...0&d=1292890511
O=max range, U=min range

The upper range for sensor output is 4.8v... Which should be around 160bar or ~2350psi...


I think the sensor limit seen by the ap and dahdaq is just a PID limitation, in normal operation a value greater than ~2000psi would never need to be displayed... Just like the AP boost display limitation that was just fixed with the NEW AP..

Regardless, great job finding this sensor.. As soon as we geat an upgraded rail valve this thing will be very useful... with both data sheets it'll be easy to adjust the FP with both the AP or the SB to account for the extra sensor range...


The SB intercepts the signal directly from the sensor, the AP , DH, and dashdaq, read the ECM output via the canbus..

I wonder if internally the ECU can understand 4.8V but the OBD2 PID is clamped at 4.5V, Much like before Cobb fixed the 3 bar map sensor support, the ECU could read the sensor fine if you altered the settings in ATR, just the OBD2 PID's werent working properly.

sounds plausible to me but who just said that the AFR goes way rich when you hit peak pressure?

Your not taking into account all possibilities

A. Sensor is putting out somewhere imbetween 4.5V and 4.8V causing the OBD2 PID to display incorrectly but internally for fueling calculations the ECU still reads it fine.

B. Sensor is putting out somewhere imbetween 4.5V and 4.8V causing the OBD2 PID to display incorrectly AND the ECU doesnt like anything north of 4.5V causing it to run rich.

C. Sensor is maxed out at 4.8V which will definatly cause the ECU to run rich.

So depending on how high your fuel pressure is you could run into one of those cases.

Ahh a ressurection of my original infos from the original rail pressure thread. The stock sensor reads 2300+ net psi. It is bolt on, and its around $350 iirc.

Pressure Sensor Fluid PSS-250R

This sensor is designed to measure the pressure of media in relation to the ambient pressure (e.g. Diesel, gasoline, water, engine oil, transmission oil or air). The sensor is available for two different supply voltage ranges. The sensor uses stainless steel measuring cells with piezo-resistive measuring bridges in thin layer technique, which are hermetically welded together with stainless steel pressure ports. This guarantees a complete media compatibility. The main benefit of this sensor is the high quality of a production part at a low price.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~

Application

Application 0 … 250 bar (r)

Pressure Reference Type relative

Max. Pressure 500 bar

Operating Temp. Range
[1] -40 … 125 °C (140 °C)
[2] -40 … 125 °C

Media Temp. Range
[1] -40 … 125 °C (140 °C)
[2] -40 … 125 °C

Storage Temp. Range -20 … 50 °C

Bio fuel compatibility -

Max. Vibration 100 m/s2 rms @ 10 … 2,000 Hz

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Electrical Data:
Power Supply US [1] 4.75 … 5.25 V [2] 8 ... 30 V

Max Power Supply Us max ± 30 V

Full Scale Output UA
[1] 10 … 90 % US ratiometric
[2] 0.5 … 4.5 V non-ratiometric

Current IS 8 mA

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
Mechanical Data
Male Thread M10x1

Wrench Size 17 mm

Installation torque 15 Nm

Weight w/o Cable 45 g

Sealing O-ring 7.65 x 1.63 mm

Characteristic Response Time T10/90
[1] 1.5 ms
[2] 1.0 ms

Compensated Range 0 … 90 °C

Tolerance (FS) @ US = 5 V ± 0,1 bar

Tolerance (FS) ± 1 %

Sensitivity:
[1] 16 mV/bar @ US = 5 V
[2] 16 mV/bar

Offset:
[1] 500 mV @ US = 5 V
[2] 500 mV

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
Connectors and Wires
Connector Bosch Compact Mating connector
[1] D 261 205 339
[2] D 261 205 334

Pin 1 GND
Pin 2 SIG
Pin 3 US
Pin 4 -
Pin 5 -

Sleeve DR-25

Wire size AWG 24

Wire length L 13 … 95 cm

Various motorsport and automotive connectors are available on request.
Please specify the required wire length with your order.

Part Number:
PSS-250R [1] B 261 209 965-01
PSS-250R [2] B 261 209 067-01

Based on what my car did when I used 2100 desired through ATR and the success standback guys have had upping their pressure I would have to guess B. B or C for sure, because even with 2000 desired I am getting extremely rich at the top of the RPM range (and peaking somewhere just north of the 2074 limit.)

Well, speaking of possibilities, here's an important one to consider:

D. Sensor is maxed out at either 4.5v or 4.8V (either one), but the ECU is commanding higher pressure yet.... and fuel rail explodes.


This is a legitimate concern with a maxed out sensor. And even if there has to be some level of "intentional fudging" of target pressures to use the new valve... at least it prevents a clipped sensor.


intentional fudging would be targeting like 900psi at wot with the new sensor, cause you know that the voltage corresponding to 900psi = 2100 psi in real life, or something to that effect.

Oh, and IIRC sumark had a 12 volt line shorted to the fuel pressure sensor, and his ecu reported up to like 6500 psi or something ridiculous like that. So, afaik, there's no limit to the ECU's interpretation or reporting of fuel pressure.


Lemme see if i can find some posts from when that happened to him.

I recall that craziness...

Thats good, cause i can't find any logs, pm's, email's or posts stating it specifically... lol

Was that a dashhawk/obd2 reading 9000 psi or a standback?

Remember just because the standback reads 12V as 9000 PSI doesnt mean the stock ECU does.

06speed6 does that sensor fit our rail? Because the one i linked is indentical. That one looks quite a bit different

IIRC it was DH, but shit... those memories were in the cobweb part of my brain.

Easy enough to check though, i'll try to do it some time after the holidays.

this thread is pure win...its fun to set back and watch the gears turning in you guys' heads..

:biggthumpup:

ha i answered a question before ssinstaller... can i be in the msf smartypants club?

keep that brain juice flowing