Fuel Computer Memory Program Numbers.

[Robsey]

Hi All,

In a recent thread, I mentioned that my fuel computer had the wrong program number.
This will not mean a lot to some people, but the general gist is that for the fuel computer to provide accurate figures, it needs to use certain values to make the calculations.
These values are:-
Engine Type (ECU type).
Road Wheel Size and tyre profile.
Miles or Kilometers.
Analogue or LCD instruments.
plus a few other bits n bobs that affect the overall fuel consumption data.

A fair few moons ago, I downloaded Ian Till's "Memories" Excel spread sheet.
I am not certain as to what state of dis-repair his old website is in - it was called ABS-Zero.
From memory, I understand that Ian is now highly placed in the VBOA, hosts of the annual July Auto-Jumble etc, now at Market Harborough, formerly the old Billing event.

I am re-presenting it here but with only the Cavalier memories..
And with a few minor corrections.
I did toy with the idea of listing Calibra too, as program No 130 is the most common.
Perhaps something for the future...

So here is the table in glorious techni-colour to make some options easier to spot.







The program numbers can be used to get your fuel computer set up correctly, if you ask your dealer or any acquaintances that you know may have an original "Tech 1" diagnostic / programming tool by Vetronix.
I would not be surprised if it is only independent vauxhall specialists now that have Tech 1, as I am sure Vauxhall dealers will not care to support older vehicles.

[Robsey]

If you want to know...

To find display fields 1, 2 and 3 you need to turn on the ignition.

Press both the raised button and the long recessed button at the same time for about 5 or 6 seconds.

Field 1 will show in the top window of the display.
Field 2 will show in the bottom window.

If you now let go of both buttons, fields one and 2 will disappear, to be replaced by field 3.

Simple.

After a few seconds the display will revert back to standard -
The desired selection from the list in the top window, and the time in the bottom window.

[Tobias_CDX]

The link to all codes for all model years:
https://www.opel-infos.de/downloads/vectra_a_bc.pdf

[Robsey]

Very useful - thanks.

I have 2 questions now...

1 - Is there anything to say which speed pulse is used on any specific car ?

2 - more an observation, but my engine is from a 1993 Diplomat with C20NE engine,
But the listing in the link does not give a C20NE with miles setting. Only Km setting.
To make matters more confusing, in the 1994 list I see 3 choices of speed pulse - 5458, 6200 or 6500.
Hence question 1.

[Tobias_CDX]

1 - 15458 pulses you have only with electronic speedometer (speed starts with 0) showing K-number at dial. Only used with V6 and 4x4 MY1993 onwards. 8350 pulses only with F28.
8664 pulses with speedometer W=1083 and 8544 with W=1068. In MY1994 pulse generator was changed, speedo remained the same. Pulse numbers depend on wheel size.

2 - column 3 of "Motoren" is also for C20NE. Column 5 with C20NE is just for Japan, but I don't know whats the difference between the codes. For your car MY1993 you will need 37 or 94.

[Robsey]

Thanks for that...
That is a great help,
I still have my old analogue speedo, so will be able to see what the markngs are on the dial face.


Ah now then - I have looked, and my speedo says W1742.



If I think correctly, this is for a mph speedo.
So if I convert to kph by multiplying 1742 by 0.61, this gives nigh on 1080.
So possibly my figure is 1083 per kilometre of travel.

So according to Tobias' comments that should relate to 8664 or program number 37.

[Robsey]

So today James very kindly programmed my fuel computer to code 037.
Took me ages to find the post in my thread, but found it eventually

This gave James lots of time to do a full diagnostic check - and a batch of actuator tests. All working fine according to the man with the black plastic brick (Vetronix Mastertech Tech 1a tool).

Drove home and was getting between 77 and 80 miles per gallon...
Hmmm - sounds a little optomistic.





This seemed very familiar.
I got the car up to 70 on the motorway.
Engaged cruise control to hold the speed steady.
Changed the computer function to average speed and then reset the values.
Lo and behold my board computer reported 139 to 140 mph.

Double the speed, so incorrect pulse setting.
037 is 8780 pulses.
I need as near as possible to double. (17560 pulses).

In my WIP thread, using basic mathematical calculations, I estimated the desired figure to be 17100 pulses.
As mentioned earlier it will need changing to (1)6500 pulses.

Perhaps 1742 is actually 17420, and thus why 16500 is the most accurate / nearest value available.

Correct code index / program number should have been 105. My mistake.

Ah well - I will need to wait until Vauxfest for a second attempt.
Or buy a Tech 1 myself. Assuming I can find one that works for sensible money.

Just to finalise, my motorway mpg must be around 38 to 40 mpg at 70 mph.

[Kevster]

Rob,

I tried making contact with Ian Till over a year ago when I was looking to have the chip programmed on a computer from a V6 to suit retro fit in to my XEV.

Eventually he replied said he could sort it and then went quiet and totally ignored me since.

He has a newer website but links are broken and doesn't appear ro be cared for much.

However there is a guy in ClubCalibra who sorted it, no.129 for the XEV and worked spot on. (I just posted the chip to him) I think it a little optimistic on mpg but not too bad, haven't done an actual long hand check.

[Robsey]

All trip computers are a little on the optomistic side.
James said this to me yesterday.

Ian Till stopped doing programming by post, and used to offer to do diagnostics and programming at meets and rallys.
He is on the staff at VBOA, so presume he would have been at Market Harborough over the weekend.
In his current designation, he may be "above all that" now.

Without "diss'ing" Ian I found him just as difficult to contact 10 or so years ago.

This is why I chose to ask my fellow admin James, who did a full diagnostic check as well.
All for free, although I did insist on giving him some beer money.
It is only fair.

[George Vec]

Hello to all. I own a vectra a 1988 model with the 16sv carburated engine. I want to install a fuel computer but i do not know if it is even possible. I hane the wiring for the button under the handbrake but i do not know if i fave the yellow plug behind the dash yet. I want to know if it is even possible to get a reading from this engine.

[Robsey]

So you have an SV.

Okay, from memory that is purely ignition control, not fuelling.
EZ Plus set up.

I have looked, and can see that you car will have: -
rpm signal,
a tank level sensor.

What I cannot find is the wheel speed pulse signal.
I am sure the pulse module on the back of the speedo unit were never fitted to 1988 cars.
You could fit a speedo cluster from a later model Cavalier with the pulse module on the back of the speedo itself.
And add the necessary wire between speedo cluster and the computer.

BUT -
There is no fuel injector pulse signal as you have a carburettor fuel set-up without any electronic control system.

So in simple terms, I do not believe that the computer will work.
As it will simply not be able to detect fuel usage. (Flow rate etc).

[George Vec]

Thanks Robsey. The cluster is changed a few years ago beacause the paint was faded out. How can i recognise if it has the speed module iserted? So if i put it on i would only see outside temp, stopwatch and average speed? I guess range is also calculated through the consumption. Is there a way to trick it to show at least a fake number istead of the F?

[George Vec]

I thought something but i think it is kind of stupid. Can i get a c16 ecu from breakers and wire it with the spare connectors in the kick panel just to give that pulse?

[Robsey]

Without the fuel injection / flow rate information, you will always get the "F" in the display.

I do not know how the fueling pulse is transmitted. Voltage, resistance or pulse-width modulation.

As you suspect though,
You will only get time, temperature and average speed.

Consumption and range do indeed rely on the rate of fuel usage to calculate.

As far as I understand, a speed pulse generator speedo will have a little black block on the back of the instrument cluster casing, close to the speedo cable connection stub.

As for any other ECU, I do not think it will work.
Other than getting rid of the F, you will not gain anything.

[George Vec]

Ok! Thank you again for the information!