Fitting a fuel computer ....

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Capt Ham
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Fitting a fuel computer ....

Post by Capt Ham » Tue Jul 26, 2016 6:00 am

Completely new to this, so please treat me gently ......

Just got a 2nd hand 1998 2.5D AFT and was looking (as a first project) to fit a Reveltronics Universal Trip Computer (UTCOMP)., so I can monitor mpg, fuel use, put in temperature and voltage alarms etc....etc....

Digging around in wiring diagrams and techy bits I can see that for fuel consumption I need two particular signal inputs to enable this ....
1. Vehicle Speed Signal (VSS)
2. Fuel consumption signal (PWM or FREQ) or on instrument panel (TDI, HDI etc..)

Reading several forums (particularly on fitting a cruise control), it seems that the. VSS signal can probably be got from the speedo on the instrument cluster. Anyone else tried this?

The fuel signal seems to be a different matter. All the petrol engines look as if they have electronic injectors which give this signal, but the diesels have a mechanical fuel pump. Are there any experts out there who might be able to explain how (or if )it is possible to get a suitable signal from the diesel injectors?

Cheers.
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Re: Fitting a fuel computer ....

Post by Bongolia » Tue Jul 26, 2016 8:16 am

Interesting project that. Not really sure of the fuel monitoring benefit but it seems to be employed in other functions by the unit,so.
As I understand it the bongo diesel pump is, thankfully, all mechanical. :)
The only way I can see of you picking up a crude signal is by inductive clamp around an injector pipe.
So I would be looking at inductive timing light adapter clamps. these fitted to number one cylinder pipe and created a signal that allowed strobe light to be used for checking ignition timing. Cannot see another way to get a injection pulse from that pump.
This would only really give you a crude injection signal and not the duration of that signal unless this unit is clever enough to interpolate the duration from the signal.


Best of luck.
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Re: Fitting a fuel computer ....

Post by mikeonb4c » Tue Jul 26, 2016 9:04 am

Personally i've found that resetting the trip and filling brim to brim is a simple and effective way of building up accurate fuel consumption data. Unless a mod is going to be really useful i'd advise keeping things simple. Novelty tends to fade and legacy of ageing ancillaries tends to grow over time. But if you do succeed with it it would be great to read a write up as i think it'll be a first.
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Re: Fitting a fuel computer ....

Post by Bongolia » Tue Jul 26, 2016 9:20 am

I will second that.
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Re: Fitting a fuel computer ....

Post by Bob » Tue Jul 26, 2016 9:33 am

Welcome aboard. :D

Have to agree with the others, however when I fitted a cruise control I took the speed signal from the blue/white behind the speedo.

Housing comes out easily but remember that there are 2 wires this colour. Now you know that its obvious which one to use. :wink:
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Re: Fitting a fuel computer ....

Post by rita » Tue Jul 26, 2016 12:31 pm

Sounds very interesting, it would be very useful if you could also incorporate High Temp Warning ,Low Coolant Warning in your system/device.

Good Luck
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Re: Fitting a fuel computer ....

Post by Driver+Passengers » Tue Jul 26, 2016 12:36 pm

Previous discussion here... forum/viewtopic.php?f=3&t=65609
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Re: Fitting a fuel computer ....

Post by rita » Thu Jul 28, 2016 10:42 am

rita wrote:Sounds very interesting, it would be very useful if you could also incorporate High Temp Warning ,Low Coolant Warning in your system/device.

Good Luck
From Capt Ham....
"The kit allows for this, which was my prime motivation, but it has a lot of extra functions as well. Just trying to work out which of the extra functions I can get to work on a diesel with a mechanical ( and not electronic) fuel pump, and whether it is worth the effort. Think it would be a lot easier with a petrol version. "

Can you give us more information on the "KIT" I am sure a lot of peeps will be interested .

Good Luck.
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Re: Fitting a fuel computer ....

Post by cmm303 » Thu Jul 28, 2016 11:22 am

This the info you needed, Rita?
Reveltronics Universal Trip Computer (UTCOMP)
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Re: Fitting a fuel computer ....

Post by Capt Ham » Mon Aug 01, 2016 10:15 pm

Thanks for all your comments and advice folks. Keep them coming ..... Yes, I know the simplest thing is paper and pencil :wink: but I fancied a wee project to get my hands dirty and understand some of the workings a bit better. Still pondering if I can get some kind of basic usable info from the tacho, and then relate that to basic fuel flow ..... #-o
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Re: Fitting a fuel computer ....

Post by Bongolia » Tue Aug 02, 2016 2:21 am

Tacho would not give you the information you need.
For instance tacho would give a reading even if you were pedal off going down hill with no fuel being delivered.
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Re: Fitting a fuel computer ....

Post by cmm303 » Tue Aug 02, 2016 6:23 am

Totally off the wall and no idea about practicalities ... Is it possible to plumb in flow metres? One in the feed, other in return to tank. Consumption is the difference between the two. Could that be fed into the computer?
Chris with BertieB
'96 White unconverted AFT 2.5L Diesel 4WD
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