There is indeed. Sorry i should have mentioned that. Its all in this thread.
Z4 LPFP Sensor Retrofit
- Thread starter Jake@MHD
- Start date
Well, wouldn't you know, that's the title of the thread. Glad I could be so helpful.
I took a more detailed look into the LPFP control in the week and just wanted to put notes down on the forum as it might be useful.
There's 2 modes the DME can control the low pressure fuel pump in. The selection of which mode needs to be matched up with the EKP module as the CAN interchange is different depending on this.
Closed loop:
This is how the x35i cars control it. The DME has a fixed target of 72.5PSI, low pressure fuel sensor tells the DME the pressure in the fuel line and it modulates a PWM signal to control the speed of the pump to try and maintain that fixed pressure target. I think the control is done using a base value depending on load then using a PID controller after to add or remove PWM as needed.
The output to the EKP is just 0-100%.
Open loop:
The Z4 uses this mode. There is no low pressure fuel sensor, the DME just sends a fuel flow request to the EKP which is based off the calculated fuel injection values for the injectors. This output value to the EKP is 0-255 l/h.
For anyone that's retrofitted the sensor to their Z4 i'd be interested to see what sort of pressure they are seeing and how it varies at WOT. I can also assist is modifying their tune to allow the sensor if they are having a problem.
Also I noticed there is quite a lot of configuration available for the 335i style of control, the PID and base value can be adjusted which should stop those wild low pressure swings that people with bigger fuel pumps are seeing in logs.
I have a few extra logging parameters that can be used for logging the respective output to the EKP and also I think it should be possible to read the EKP voltage and current using MHD. I monitored the PWM value on my 335i before and after replacing the OE pump and it's obvious the new pump takes way less power to provide the same flow. It was pegged at 100% at WOT previously and was dropping to 40PSI, the new pump sits around 80% at most and gives a nice flat 72.5PSI.
There's 2 modes the DME can control the low pressure fuel pump in. The selection of which mode needs to be matched up with the EKP module as the CAN interchange is different depending on this.
Closed loop:
This is how the x35i cars control it. The DME has a fixed target of 72.5PSI, low pressure fuel sensor tells the DME the pressure in the fuel line and it modulates a PWM signal to control the speed of the pump to try and maintain that fixed pressure target. I think the control is done using a base value depending on load then using a PID controller after to add or remove PWM as needed.
The output to the EKP is just 0-100%.
Open loop:
The Z4 uses this mode. There is no low pressure fuel sensor, the DME just sends a fuel flow request to the EKP which is based off the calculated fuel injection values for the injectors. This output value to the EKP is 0-255 l/h.
For anyone that's retrofitted the sensor to their Z4 i'd be interested to see what sort of pressure they are seeing and how it varies at WOT. I can also assist is modifying their tune to allow the sensor if they are having a problem.
Also I noticed there is quite a lot of configuration available for the 335i style of control, the PID and base value can be adjusted which should stop those wild low pressure swings that people with bigger fuel pumps are seeing in logs.
I have a few extra logging parameters that can be used for logging the respective output to the EKP and also I think it should be possible to read the EKP voltage and current using MHD. I monitored the PWM value on my 335i before and after replacing the OE pump and it's obvious the new pump takes way less power to provide the same flow. It was pegged at 100% at WOT previously and was dropping to 40PSI, the new pump sits around 80% at most and gives a nice flat 72.5PSI.
If this is possible, that's a massive game changer. I'd love a flat line for my lpfp. I find it interesting that even though a E60 comes with a bigger pump from factory it still suffers from fluctuations once fuel demands increase.
No one knows why. The E89 is significantly different vehicle, even in its variants of other parts (like the E46-based rear suspension parts ... that are not actually the same as the last E46's).
We like to kid around and say that the Z4 was designed by interns.
But ironically (and I don't understand this to this day), people say that a stock Z4 is like a stage 2 LPFP on a 335i. ..........
As for your question on the LPFP sensor addition, there is information on the this thread. At the end of the day you have to know how to pin/depin the connectors. Ken did it with an E90 harness next to him so it was color by numbers - just chased the wires/sensor to the DME connector, noted the pin out, pulled the sensor/wires, installed on the pins in the corresponding location on the Z4 DME connector.
I'm not going to be at my PC for another week or so but if you let me know what ROM version you are on I'll make a custom MHD logging file up that will let you monitor the signals needed to tune to lpfp.
Once we know what part of the controller causes the overshoot we can tune it better.
Unzip this file and put it in the root of the android MHD folder. You can can then select some extra channels that should let us see what part of the LPFP calc is off.
Just make sure you log all the extra channels. They all start with 0 so are at the top of the param list. Also make sure you have the low fuel pressure sensor logged too.
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I'll do my best to get a log as soon as possible, just need the weather to collaborate.
It's pin 7 and 8 of A60005. That's the long double row in the image below. I've never checked if that's wired on the Z4 harness. It's probably already in the harness. I think Wedge did the retrofit so will know where it needs connecting.
I don't know what code changes are required to get it to read. I only know what code changes are required for a complete conversion to closed loop LPFP control. I remember that the input scaling needed to be added into the ROM but you can always just plug it in and see what the logs look like.
I don't know what code changes are required to get it to read. I only know what code changes are required for a complete conversion to closed loop LPFP control. I remember that the input scaling needed to be added into the ROM but you can always just plug it in and see what the logs look like.
| Pin assignments at plug connector A60005 | |||
| Pin | Type | Description /Signal type | Connection /Measuring notes |
| 1 | -- | Not used | |
| 2 | -- | Not used | |
| 3 | A | Activation | Volume control valve |
| 4 | -- | Not used | |
| 5 | -- | Not used | |
| 6 | -- | Not used | |
| 7 | M | Ground Low pressure fuel sensor | Low pressure fuel sensor |
| 8 | A | Supply Low pressure fuel sensor | Low pressure fuel sensor |
| 9 | M | Negative supply | Intake temperature - boost pressure sensor |
| 10 | E | Signal Boost pressure sensor | Intake temperature - boost pressure sensor |
| 11 | A | Positive supply | Intake temperature - boost pressure sensor |
| 12 | -- | Not used |
The pins on A60001/2/5/6/7 all require "TE 175062-1".
I don't think BMW sell them but you can buy from them RS or Farnell. I ordered a load of pins so got them as part of a bulk order from TE directly.
You might need a crimp tool for them. I did all mine by hand since I am using them purely for a bench setup but for use in your car you want to do a proper job.
You should check if all this is required though. I'd be shocked if those wires aren't already in the Z4 harness.
Hello.So i need to connect LPFP sensor to 6005 or 6001 i am a hit confused.?
Hi all, I’ve been lurking in the back for a few months. I am from South Australia and have a 2009 Z4 35i with MHD stage 2+ and I recently upgraded the LPFP to a Walbro 535. My HPFP crapped itself a few hundred kilometres later and I’d like to add a low pressure fuel sensor to monitor what is happening in that side of the system. I also wonder if the lack of a low pressure sensor and closed loop LPFP control on the Z4 is a reason why I consistently miss boost target by 2.5-3psi? If I manually limit the boost target to 15psi (or less) then I generally come within 1psi of it. I’ve found an engine wiring loom and sensor line from a 3 series - going to attempt to at least set it up for monitoring.
