Faulty Fuel Gauge

Turbo doesn't have a flow meter Jon .Injection wizardry innit .

Turbo doesn't have a flow meter

Thanks fot that Lee, but the above clearly does still apply to the Atmo.......However I am puzzeled on a couple of points..... In my 1990 Model Year Electrical Manual, listed in the "Units Illustrated" page, under "V6 Turbo RHD"... page 16 is refered to as the "Flowmeter Signal", which as it happens, is the same page as the "Speedometer". Unfortunately I only copied Pg 15 when I had the chance as it covered the Atmo cct. I do note that a Flowmeter is not shown in the 1986 "Fuel Gauge cct".
The other point is that in the "Detecting Faults" section of in the Fuel computer display in the main manual,it refers to a Flowmeter, and has one fault finding discription which implies that it covers both Turbo and Atmo and does not differentiate between the two. I wonder if they fitted a Flowmeter in later models together with the TSU, the later not being fitted to the early Alps.
Is there is anyone out there who has a 1990 Model Year Electrical Manual who could scan the cct on page 16 for me please, I would very much appreciate it,

John

[img]
http://i297.photobucket.com/albums/mm22 ... sGTA16.jpg[/IMG][/img][/url]

John,

Have a look the link - hopefully I've uploaded it ok.

If not, then let me know your email address and I'll email you a copy.

Rgds

Paul

[img]
http://i297.photobucket.com/albums/mm22 ... sGTA16.jpg[/IMG][/img][/url]

John,

Have a look the link - hopefully I've uploaded it ok.

If not, then let me know your email address and I'll email you a copy.

Rgds

Paul

Hi Paul,

The image has`nt materialised I`ll PM my email, Thanks

John

It's sort of fixed itself today .Suddenly started to count down .....but then counted up for a bit then down It seems about right but now the readout gives all the 88888s whenever the car is restarted .I then hold the reset and it sorts itself out.

[BIG_MVS]

Come on guys back to school.....

..........Oh dear, I`ve done it again Martin, When I said Page 16, I was refering to the circuit page number, not the actual page No. The Cct pg No. that you sent was 4, also the title of, lets call it, Plate 16 should be the "Flowmeter Signal", sorry for the confusion.

Cheers

John

It's sort of fixed itself today .Suddenly started to count down .....but then counted up for a bit then down It seems about right but now the readout gives all the 88888s whenever the car is restarted .I then hold the reset and it sorts itself out.

Hi Lee,

This has got to be a poor connection somewhere. But I have had further thoughts on your prob, and even if the Turbos hav`nt got the same type of flowmeter as the Atmo, the Turbo must somewhere produce a stream of pulses, be it from the ECU or something else, which are proportionate to the fuel being used. I am awaiting some info re:- the Turbos cct to see where they must come from. Because I suspect, but I could be wrong, that the same fault diagnosis as in the manual, will apply to both types of Alp, irrespective of where the flow signal is generated from.
You say that it shows 88888 every time you start the car, this usually only occures when the batt is disconnected then reconnected. I would look at the connectors behind the inst` panel as it is almost like the connector supplying the 12v to the panel, being intermitent, is remaking itself with the surge on the 12v supply due to the action of the starter. If it were me I would have to check that first.

John

I understood and find that you get "all 8s" when running the trip computer in diagnostic mode.

When in diagnostic mode the petrol gauge will fluctuate as the level slops about and the other readout is from the flow meter, which is the amout of fuel being delivered. about 1.1 on idle, 8-10 at a cruse of 2500 rev and upto 60 odd when in hard acceleration conditions.

And yes, you have to press the dash "mode" button each time you start the car.

The get out of diagnostic mode, press the reset button on the trip comp.
To get into diag mode, disconnect the battery for a couple on minutes.

Hi Simon,

You make some interesting points the first of which is your reference to the flowmeter when I note you have a Turbo. What is your understanding about what passes for a flowmeter in the Turbo?
Now to your other points:-

I understood and find that you get "all 8s" when running the trip computer in diagnostic mode.

I find that all the 8`s appear each time the battery is reconnected and change the moment you press either the reset or mode button the later of which will then take you into the diagnostic mode.

And yes, you have to press the dash "mode" button each time you start the car.

Dont quite understand why you have to do this "each time you start the car". I dont, I only press it to change the mode display, or did you really mean the reset button in the rev counter?

The get out of diagnostic mode, press the reset button on the trip comp.

No problem with that, however:-

To get into diag mode, disconnect the battery for a couple on minutes.

My understanding of getting into diagnostic mode, as I mentioned above, is to:- disconnect battery...press reset button for a good 15secs...switch on ign...then "All segments should be displayed". You then have to press the mode button once to get into diagnostic mode, then you can continue your checks which for info of other interested members are:- ......To check flowmeter signal:-...press mode key again...2 digits on left = Fuel remaining (as you say will vary due to slopping)...2 digit display on right = Signal frequency from flowmeter ......To check the speedometer:-...press mode once again...2 digit on left = Fuel remaining...2 digit display on right = information on speed with car moving.

Cheers

John

There is no flow meter on the turbo .It calculates all the readings via the ECU except for fuel level .I don't have any of the other fuel readings such as MPG ,distance etc as I'm running the Adaptronic but I still get the fuel level as that comes directly from the tank sender but obviously the two must talk to each other somehow .....
I have to reset the clocks each and every time I restart ,whether the battery has been disconnected or not .This though has not always been the case when running the Adapt, it has started doing it over the last few months .

There is no flow meter on the turbo .It calculates all the readings via the ECU except for fuel level .I don't have any of the other fuel readings such as MPG ,distance etc as I'm running the Adaptronic but I still get the fuel level as that comes directly from the tank sender.

A question I would like to ask you is if the fuel gauge has ever worked correctly from the day you fitted the Adaptronic ECU. Also was it playing up before you fitted it?
The reason I ask is that a thought has been going around in my mind that due to the odd shape of the fuel tank, and an obversation that the fuel gauge does not drop more quickly from a full tank state, than when it gets to the flatter part of the tank lower down, which I maintain it should, due to the linear properties of the sensor, if you know what I mean, I am thinking that on switch on the level is recorded on the gauge, then the flow rate is used to reduce the fuel level reading.
Any thoughts other members have on this theory would be welcomed
With regard to your distance not being recorded, this as I am sure you know comes from the speed sensor......which I think you said was not connected, so I take it your speedo aint working either

Cheers

John

Nope no speedo ,I use the Drivesmart spee.....safety camera detector/GPS .I just need to hook up the speed sensor and then that wont work as well
Hey but the engine works well , that's all I'm bothered about .

Yes ,the fuel sender has worked before just fine with the Adapt .

Yes ,the fuel sender has worked before just fine with the Adapt .

Oh well......bang goes my theory then ....Anyway my thanks to Paul who emailed the Turbo`s cct to me,....Lee was right...again the Turbo does not have a Flowmeter Unit as fitted to the Atmo. However somehow the ECU is capable of producing some form of signal which is used by the Computer to give it the info it wants to calculate MPG. but as I indicated any failure in this signal not reaching the computer will, like the manual says, cause the display to flash.
I have highlighted the fuel flow signal path in BROWN on the cct below in case anyone is interested, plus the rest of the cct for the operation of the fuel gauge. You will see that the signal comes out of R5 then splits, one going to pin 12 of the computer connector, which is the same input pin as used for the Atmo. but the other one goes to pin 7, which is a different pin to that on the Atmo,
Hope this is of interest

John

Hi Simon,

You make some interesting points the first of which is your reference to the flowmeter when I note you have a Turbo. What is your understanding about what passes for a flowmeter in the Turbo?
Now to your other points:-

I understood and find that you get "all 8s" when running the trip computer in diagnostic mode.

I find that all the 8`s appear each time the battery is reconnected and change the moment you press either the reset or mode button the later of which will then take you into the diagnostic mode.

And yes, you have to press the dash "mode" button each time you start the car.

Dont quite understand why you have to do this "each time you start the car". I dont, I only press it to change the mode display, or did you really mean the reset button in the rev counter?

The get out of diagnostic mode, press the reset button on the trip comp.

No problem with that, however:-

To get into diag mode, disconnect the battery for a couple on minutes.

My understanding of getting into diagnostic mode, as I mentioned above, is to:- disconnect battery...press reset button for a good 15secs...switch on ign...then "All segments should be displayed". You then have to press the mode button once to get into diagnostic mode, then you can continue your checks which for info of other interested members are:- ......To check flowmeter signal:-...press mode key again...2 digits on left = Fuel remaining (as you say will vary due to slopping)...2 digit display on right = Signal frequency from flowmeter ......To check the speedometer:-...press mode once again...2 digit on left = Fuel remaining...2 digit display on right = information on speed with car moving.

Cheers

John

Yes, I have a turbo.
I "thought" that the car had a flow meter, but as Lee says, it is the ECU that "calculates" fuel used as a sum of all fuel injected into the engine.

After I re-connect my battery, when ignition is turned on for the first time, and subsequent times, so long as I only press the dash mode button, the unit will stay in diagnostic mode and I like to see the real fluctuating fuel level. As soo as I press the reset button on trip computer, then the computer goes into normal mode and I get MPG and MPH and range displays (but only when the speedo is working too).

Have a look in the workshop manual, it tells you about trouble shooting the trip computer and the componants that feed data into it.

Good thread!