FREELANDER with BMW DDE Version 4.0 System

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Re: FREELANDER with BMW DDE Version 4.0 System

Postby STC » Sun Oct 16, 2016 4:45 pm

I tried a new air mass meter today and although the readings are now equal or above the desired g/s the fault code still appears, that is the P1260.

You had good evidence to condemn the MAF but I think you secretly knew it was unlikely to cure the P1260. How many times have we swerved a fault code thinking its unrelated to the fault and then it comes back and bites us.

Had a word with AD and they think it is either a software related issue or a fault in the ECM


Then they need shooting !! Right between the eyes !!

That ECM & its software has 3 concerns with the LP fuel Circuit
1. To Click the Relay in and switch the Pump on
2. To monitor fuel pressure and throw a DTC if the pressure is wrong.
3. Push accurate LP Pressure to your scan tool

Its doing all 3 jobs marvellously well from where I am sat ??

KOER terminal [3] = 1.64V @ idle
KOER terminal [3] = 1.54V @ 2500 RPM (Max rev's)
KOEO terminal [3] = 2.1V (with codes cleared). [pump is running here]


That looks wrong to me. Have you got wiring or Pin Grab issues in the connector. It is a long thread now but would I wrong in thinking you appear to be getting different readings every time you make a measurement ?

Working on the principle that your fuel pump is causing Fuel to Flow & Not creating Pressure.

From the Diagram above my understanding is that item 11 -"Pressure Relief Valve" is the calibrated "Restriction" responsible for creating then maintaining the correct pressure in the circuit between the outlet of the LP pump and the Inlet to the HP Pump. I'm thinking it "Reliefs" anything above 2.6 bar. If that is the correct Pressure Figure. I will try to verify that later from another source.

If that Fuel Pump is NOT demand controlled, the diagrams suggest it is not. Then If the pressure relief valve in the tank does not have wires, cables or Bluetooth then it should maintain a constant pressure unless its broken ? or controlled by something.
The figures above shouldn't move - Ever ?

I have also measured the low side fuel line pressure with KOEO pump not running and found the line pressure holds 1.4 bar stable

That proves you don't have a leak. You need to be testing that with the Engine & LP pump Running.

If not already done, Scope the Power and Earth at the pump, Amp Clamp on the 3rd Channel, Fuel Pressure sensor on the 4th channel to rule out any Relay or Control Issues responsible for the LP figures dancing around. Wire a 55w bulb in parallel to load it up (might blow the fuse) but it will confirm the circuit.

While you have the scope out, leave the Amp Clamp on the pump then poke 2 into the pressure sensor supply pins, the last into the Sensor signal ideally back probed at ECU


I have then connected the pressure gauge to the low side pressure line directly from the fuel pump and filter and completed a KOEO pressure test for the supply to the Common Rail, I recorded [2.6] bar with the pump running.


Now I am reading this wrong or Baffled !! That tells me that you have your pressure Gauge Teed in to the very same piece of fuel pipe that Item 16 - Pressure Sensor is fitted into and you reading 2.6 Bar - The Correct Pressure, In the correct part of the LP Circuit, with the pump running hence correct test conditions ????

Does it look like I have a problem with the HPP?

In theory, you could unbolt the HP Pump, cut it in half, throw it in the dustbin, securely block the inlet pipe (the one with the LP sensor in it) Then run the LP pump and maintain 2.6 bar all day if the LP side is functioning correctly. As long as the Relief valve in the tank is fixed and not variable by design.

Educated guess, but In short it is critical that you have a constant 2.6bar in 4 Places and P1260 will go away ?

1. At the measuring surface within the Pressure Sensor to keep the ECM happy
2. At the inlet of the HP Pump so the party can start, so to speak.
3. On the screen of your diagnostic tool.
4. On your Gauge which is T'eed in for independent verification.

I would advise that you limit your initial testing to those 4 places only. Measure where the ECU is measuring, and where it needs to be.

Bosch suggests that your system pressure should be 2.5bar. The pressure sensor at 2.5 bar should have 2.6 - 3.0v on the signal wire. I would trust that over the 4.3v AD are quoting, makes more sense.
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Re: FREELANDER with BMW DDE Version 4.0 System

Postby andrewbishop66 » Sun Oct 16, 2016 7:56 pm

Hi Tech

I have to agree with STC about ecu as your pressure is not staying constant therefore the ecu is doing its job right by reporting low pressue

looking at the fuel schematic you should have 2.5bar at the HP pump

KOER provides 0.6 bar low side fuel pressure [Gauge reading]


now have I got this wrong or is the HP pump over running the supply pulling the pressure low

you have 2.5 bar at KOEO but when you put a demand on the fuel line the pressure drops as it cant meet the supply demand (restricted flow)

I think Im right in saying you said that with fuel pressure sensor disconnected it ran ok for a while and then the smoke issue appeared
That would also suggest the ecu is doing the job of protecting the engine from starved fuel supply and that could be the strategy for the fault code

Just my musing could be miles off

Thanks Andrew
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Re: FREELANDER with BMW DDE Version 4.0 System

Postby STC » Sun Oct 16, 2016 9:05 pm

Technician
I'm going to rest my brain now for a while


I know how you feel, I too see feelings of frustration creeping in as you are either not reading & absorbing the posts or not fully understanding the system strategy. With the latter, ask a hundred times and I for one will reply and help each time.

I have Topix to hand so rest assured I have given you everything I have found relevant to your fault, your are equipped now with almost everything the dealer tech would have. Add to that the Info from ESi.

And I think you are sending out conflicting test results, the whole thing does not have any hint of consistency or methodical direction.

I made a big deal of the Pressure Regulator in the tank and 2 very easy scope tests in my last post. You absolutely acknowledged neither yet your "Silver Bullet" could be right there.

I have suggested several tests in the threads, others have too.

Print this thread, pick out all the test suggestions and swipe the rest. Keep that car a day longer conduct the tests and I really believe you will nail it.

You bang on about it being the ECM or HPP. Do you want to fix it or Just Fire the Parts Cannon at it (JD Trademark - Sorry)
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Re: FREELANDER with BMW DDE Version 4.0 System

Postby Technician » Mon Oct 17, 2016 9:13 pm

Hi STC,

I am sorry I didn't acknowledge the following information from you;

From the Diagram above my understanding is that item 11 -"Pressure Relief Valve" is the calibrated "Restriction" responsible for creating then maintaining the correct pressure in the circuit between the outlet of the LP pump and the Inlet to the HP Pump. I'm thinking it "Reliefs" anything above 2.6 bar. If that is the correct Pressure Figure. I will try to verify that later from another source.

If that Fuel Pump is NOT demand controlled, the diagrams suggest it is not. Then If the pressure relief valve in the tank does not have wires, cables or Bluetooth then it should maintain a constant pressure unless its broken ? or controlled by something.
The figures above shouldn't move - Ever ?

I have also measured the low side fuel line pressure with KOEO pump not running and found the line pressure holds 1.4 bar stable

That proves you don't have a leak. You need to be testing that with the Engine & LP pump Running.

If not already done, Scope the Power and Earth at the pump, Amp Clamp on the 3rd Channel, Fuel Pressure sensor on the 4th channel to rule out any Relay or Control Issues responsible for the LP figures dancing around. Wire a 55w bulb in parallel to load it up (might blow the fuse) but it will confirm the circuit.

While you have the scope out, leave the Amp Clamp on the pump then poke 2 into the pressure sensor supply pins, the last into the Sensor signal ideally back probed at ECU

I had other parts of the fuel system under the bonnet in bits at the time pressure testing and didn't have the time to complete those tests, which are very valuable and are very much appreciated.

The Land Rover is not yet finished and I have not got a lot of free time to devote to it, primarily at the moment I get to it when I have free time to spare, which is why I have not been able to follow through with all your advice, but please be assured I will try any suggestions you provide, I do very much appreciate your help.

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Re: FREELANDER with BMW DDE Version 4.0 System

Postby Dcunning35 » Sun Oct 30, 2016 5:48 pm

Technician ,David whatever your name I cant stress enough how much tho forum assists all off us professionals,nobody knows everything But this is a place to show respect for other users especially when they act in good faith to offer assistance.
As for Stc,s capabilities as a practising diagnostician I think his actual qualifications !! Experience and passion for the Job speak for themself .
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Re: FREELANDER with BMW DDE Version 4.0 System

Postby AuthorMike » Mon Oct 31, 2016 9:09 am

This thread has been cleaned and closed. If you have anything useful to add to this thread, please feel free to PM either myself or another administrator.
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