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Old 2nd July 2019, 16:15   #1
Mickyboy
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Default IPK mode 19 sub section 6 verified

Today I carried out some in depth analysis of IPK mode 19 sub section 6 and thought I’d share this with everyone as I’ve noticed recently users have been mentioning fuel level fluctuations on the gauge itself.

So what I did was I was looking to see if during the IPK mode can correctly analyse the fuel being added to the tank and the fuel level in the tank in litres correctly I have attached some photographs as you can see


The photo below shows that the car has approximately 10 L of fuel in it



The following photo shows that I added exactly 10 L of fuel at the pump


The following picture below shows the diagnostic mode after adding exactly 10 L of fuel, it shows clearly that 10 L have been added

Therefore it shows quite clearly that IPK diagnostic mode 19 subsection 6.2 can accurately determine the quantity of fuel remaining in the tank, as long as the first digit is one i.e. 1.6.2 as the first digit indicates both senders are receiving a signal if the first digit was to for example 2 it would only be getting a measurement from one sender if the first digit was 3 I believe that is an error unable to read.

I also drove whilst the figure was being displayed and the quantity of fuel did not vary by hardly any amount only slightly
I also drove the vehicle all the way down until it was on _ _0025 indicating it only had 2 & 1/2 L left in the tank, and before anybody says oh well you shouldn’t do that as you shouldn’t run them below a quarter of a tank well I did this for everybody’s benefit and also having a vehicle that has a single in tank pump system ie the later facelift version these pumps are fantastic and just never fail anyway and I’ve got a fair few in stock they never sell

I hope this has been of benefit to everyone, it just shows how accurately it can measure the quantity of fuel remaining in the tank
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Old 2nd July 2019, 18:48   #2
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That's really useful input for refining the Diagnostic Routine HowTo and valuable extra data on the Test 6.2 section. It really does need lots of checks and observations like this to fill in the obvious gaps in translating the BMW literature. .

From notes I've collected over time, I'm pretty sure that this subsection can only display as either 1.6.2 (both rheostats operating) or 2.6.2 (only one rheosat operating). The suggested 3.6.2 code (neither rheostat operating) was apparently a BMW subsection that's omitted from the MGR system and I can see the logic in that.

What I'm still not sure about is what numbers are displayed if one side of the tank is empty. For example, the notes suggest that a tank holding 4.5 litres (LHS) and 12.7 litres (RHS) will display as:
1.6.2
045127
- indicating a leading zero where the volume is below 10 litres.
By analogy, you'd expect to see '000127' if the LHS was dry. I wish there was an easy way to test that.

So, I would expect yours to show '000xyz' and not '--0xyz'. The latter was said to be shown in the faulty rheostat case, but seemingly not. You have the '1.6.2' (both floats OK).

It's also interesting that starting with a fuel tank containing around 10 litres (all in the RHS), that adding another 10 litres doesn't spill any of this into the left side. Note that all the volumes are shown as '--0xyz', even after driving around until most of it had gone. This is certainly intriguing and warrants more investigation. I only hope others will do the experiments.

TC

Last edited by T-Cut; 2nd July 2019 at 19:04..
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Old 2nd July 2019, 20:04   #3
Mickyboy
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Quote:
Originally Posted by T-Cut View Post
That's really useful input for refining the Diagnostic Routine HowTo and valuable extra data on the Test 6.2 section. It really does need lots of checks and observations like this to fill in the obvious gaps in translating the BMW literature. .

From notes I've collected over time, I'm pretty sure that this subsection can only display as either 1.6.2 (both rheostats operating) or 2.6.2 (only one rheosat operating). The suggested 3.6.2 code (neither rheostat operating) was apparently a BMW subsection that's omitted from the MGR system and I can see the logic in that.

What I'm still not sure about is what numbers are displayed if one side of the tank is empty. For example, the notes suggest that a tank holding 4.5 litres (LHS) and 12.7 litres (RHS) will display as:
1.6.2
045127
- indicating a leading zero where the volume is below 10 litres.
By analogy, you'd expect to see '000127' if the LHS was dry. I wish there was an easy way to test that.

So, I would expect yours to show '000xyz' and not '--0xyz'. The latter was said to be shown in the faulty rheostat case, but seemingly not. You have the '1.6.2' (both floats OK).

It's also interesting that starting with a fuel tank containing around 10 litres (all in the RHS), that adding another 10 litres doesn't spill any of this into the left side. Note that all the volumes are shown as '--0xyz', even after driving around until most of it had gone. This is certainly intriguing and warrants more investigation. I only hope others will do the experiments.

TC
Hi TC
As you will probably know I have a T4, and on my vehicle there is no faults indicated with my fuel level senders, this ties in with Ipk mode indicating 1.6.2 I only became intrigued by this because I carried out an experiment where I removed all the fuel from one side of the tank passenger side and still had _ _0xyz but obviously the total quantity had reduced correctly on the Ipk diagnostic display and then with it returned back into that side it still indicated _ _0xyz and the Ipk diagnostic mode then showed the correct quantity that had been returned as a total amount.
Having some experience of working on the BMW’s as I currently have on E90 LCI or should I say the wife does, I tend to agree with you that 3.6.2 code (neither rheostat operating) was apparently a BMW subsection that's omitted from the MGR system.

I shall be doing much more investigation into this with the cars I have in the yard at present mainly diesel 75’s.
I’ll try to keep you informed if you’d like
Mick
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Old 3rd July 2019, 07:13   #4
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My 1.8t 53 plate displays it in exactly the same way. Whilst trying to diagnose a fuel gauge issue and fuel supply issue (which turned out to be the pick ups on the pump being damaged from a previous removal attempt, and ffs ultimately stopping the supply) I noticed that I didn't get the full display as detailed in the excellent Ipk diagnostics thread however it was showing 1.6.2 but according to the readout it only had --0055 so 5.5l of fuel. When I brim the tank once it's mot'd I'll report back with fuel amount
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Old 3rd July 2019, 07:42   #5
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Nice one Mick - interesting stuff.

Quote:
Originally Posted by Mickyboy View Post
and before anybody says oh well you shouldn’t do that as you shouldn’t run them below a quarter of a tank well I did this for everybody’s benefit ..,
I don't believe in any of that old nonsense - if you never go below a quarter of a tank you won't know when your ITP has failed.
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Old 3rd July 2019, 18:57   #6
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Quote:
Originally Posted by Mickyboy View Post
I only became intrigued by this because I carried out an experiment where I removed all the fuel from one side of the tank (passenger side) and still had _ _0xyz but obviously the total quantity had reduced correctly on the Ipk diagnostic display
According to the write-up,

Test 6.0 shows each side volume as abcxyz

Test 6.1 shows the tank total as 'ABC' which is (abc + xyz)
Test 6.2 shows each tank side 'abcxyz' unless there's a fault with a rheostat, in which case it will show either '--0abc' or 'xyz--0'

But '--0' can't show with 1-6.2 only 2-6.2
so something is wrong somewhere.

Your results suggest the write-up is wrong, which is something I have suspected for a while. But we need lots of numbers from both sides of the tank to make sense of it. I really don't understand why driving long enough to consume eighteen litres of fuel didn't swill anything into the LHS. Maybe the hump is higher than I thought.

I'd like to do some tests again myself, but unfortunately the car's currently incapacitated and SORN. So if you're planning further experiments, could you maybe include a full tank readout for Test 6.0, 6.1 and 6.2 and then a periodic repeat of these to see how each side decreases. Logic suggests they'll fall about equally until the total gets to a certain figure, when LHS will empty faster. But it would be good to know what actually happens.
Cheers,
TC
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Old 3rd July 2019, 19:51   #7
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Hi TC
I’ll try to get a full tank readout on Friday as that’s when I fill up, it will probably however be in my facelift ZT CDTI, so infact that will give us another readout from a two pump system rather than a single pump system, not that I expect that should have any difference in the way the figures are produced.

I’ll be taking some more pictures and see where this investigation ends up
Mick
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Old 3rd July 2019, 20:11   #8
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Unfortunately my new purchase has a fuel gauge fault. Having read this thread, I checked the OBD and got the readings below. The fuel dial doesn't appear to be dropping much below half a tank. When I went to view the car, the gauge was reading jut under half a tank of fuel, but when I had her running she stalled after around 10 minutes. Adding 5L of fuel and she fired up. Adding another £20 of fuel and the dial didn't move.

_ _6.0
_ _0000


_ _6.1
_ _ _ _ _ _


2_6.2
_ _0266


This looks to show that one sensor is faulty, so does 6.1 and 6.2 specify a sensor? i.e 6.1 pump side / 6.2 filter side?

Thanks in advance.

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Old 3rd July 2019, 20:51   #9
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Quote:
Originally Posted by Typhoon190 View Post
Unfortunately my new purchase has a fuel gauge fault. Having read this thread, I checked the OBD and got the readings below. The fuel dial doesn't appear to be dropping much below half a tank. When I went to view the car, the gauge was reading just under half a tank of fuel, but when I had her running she stalled after around 10 minutes. Adding 5L of fuel and she fired up. Adding another £20 of fuel and the dial didn't move.
Many thanks for your input. We need as many readings as possible to try and get this part of the Diagnostic Routine understood.

Quote:
_ _6.0
_ _0000
This is very interesting. We see two different ways of reporting both sides empty. Test 6.0 gives the left and right tank volumes, in litres to one decimal place. But your left side shows as '__0', which is what Mickyboy sees for his empty LHS.Your RHS is also empty and displaying what I would expect for an empty side(000). Until this thread, I expected to see 000000 for a completely empty tank.

Quote:
_ _6.1
_ _ _ _ _ _
This is said to be the sum total of Test 6.0 ie. the total contents as four digits ABCD. Logically, the first digit will always be 0 since the tank capacity is only 64.8 litres. Then the B and C being litres and D a decimal. So a full tank is 0648. However six dashes for a dry tank is a new datum in the puzzle.

Quote:
2_6.2
_ _0266
This shows that one of the rheostats is faulty (2_6.2). A fully operational system shows 1_6.2 as repoted by Mickyboy. Your LHS sensor is faulty and the RHS contained 26.6 litres.
This tallies with the write-up.


Quote:
so does 6.1 and 6.2 specify a sensor? i.e 6.1 pump side / 6.2 filter side?
No, 6.1 is the total contents.

Test 6.2 is where a faulty sensor shows up. So Test 6.2 also displays either 1_6.2 (if both floats are OK) or 2_6.2 (if one is faulty). If both are faulty there'd be no digits in any test section, but we don't know if there's be any other indicator. I recall when Jules discannected both rheostats, he saw no signifier. In the original BMW system, both floats faulty was displayed as 3_6.2, but this was dropped by MGR.


TC

Last edited by T-Cut; 3rd July 2019 at 20:58..
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Old 3rd July 2019, 21:39   #10
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Forgive me if this is completely wrong, but in my totally ignorant opinion purely based on this experience I interpreted as follows:


_ _6.0 = Fuel dial input - Overall reading as percentage
_ _0000 = Indicates overall fault?


_ _6.1 = Sensor 1? Pump side? / Filter side
_ _ _ _ _ _ = Fault - no reading


2_6.2 = Sensor 2? Opposite side sensor to above
_ _0266 = Percentage reading on this sensor i.e 26.6% ( Just over 1/4 tank)


I'm guessing that a system operating as it should would give fairly equal readings across all 3. I have a couple of other cars where the fuel gauge ( was ) working, but don't have batteries on at present. I'll take a look tomorrow out of interest unless someone posts to say I've lost me marbles.

Last edited by Typhoon190; 3rd July 2019 at 21:43..
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