TDI mpg vs engine temp

[HarryMann]

Fuel consumption wise I have ran 2 tanks with new engine (AFN) both tanks have returned 6.8L/100km.

That's about 41.5 mpg!!!

[jc_geddes]

yes - I wasn't expecting it either, will keep monitoring it and will report back.

[lloydy]

yes - I wasn't expecting it either, will keep monitoring it and will report back.

Are these figures the first time you have used the scangauge? If so have you been doing the fill up procedure and adjusting the litres put in from what it thinks you used to what you actually used? I'm only saying, as it takes a few fill ups and adjustments before it learns your fuel usage. Mine started of being 10 or more litres out, now when I fill up its normally within a litre to what I used.
If you don't use the fill up part it will make it look like you are getting very good figures

[jc_geddes]

No, they are calculated. The numbers I have written down, are 667Km and I could only put 44.69 litres of fuel into the tank, that makes 6.7l/100Km.

On the fill ups I am filling the tank until I can see the fuel and am filling it to the same point every time.

I am having issues with my scan gauge and I need to change the wiring to to the obd socket, so that I have 12v for a longer period as it does not remember any trip information at the moment, so I am going to put a permanent 12volts to the obd socket from the leisure battery to try and sort this out.

The only other thing which I have wondered, as I still don't believe the numbers was to calibrate the scan gauge to the GPS speedo for speed, then look at the scan gauge trip to the speedo and the speedo trip, over a 200km trip they are all within 1% of each other so this will not make a significant difference.

The other thing to note that the engine was basically torn down and rebuilt, the bottom end just went back together while the head, as new seats and guides exhaust valves and the ports cleaned out especially the intake side due to the egr, injectors were reconditioned and fitted with larger nozzles, and a new turbo, so the engine is as good as its going to get at the moment.

But I am prepared for somebody to find an issue as I was not expecting numbers this high!

[16vmini]

I am having issues with my scan gauge and I need to change the wiring to to the obd socket, so that I have 12v for a longer period as it does not remember any trip information at the moment, so I am going to put a permanent 12volts to the obd socket from the leisure battery to try and sort this out.

exact same problem i had , and yes , i wired it to a constant 12v , as the scangauge switches off automatically once it stops getting a signal from the ecu etc...

Matt

[lloydy]

Might have found a solution to the slight discrepancy in the temp gauge! Amazingly it looks like brickwerks sell something for the very same issue
http://www.brickwerks.co.uk/shop?page=s ... egory_id=0" onclick="window.open(this.href);return false;
you can then fit the T3 sender for the gauge
I've sent them a question to ask what pipe this fits into, just so i can check it i have the space for it, so that could be good news.

[lloydy]

I am having issues with my scan gauge and I need to change the wiring to to the obd socket, so that I have 12v for a longer period as it does not remember any trip information at the moment, so I am going to put a permanent 12volts to the obd socket from the leisure battery to try and sort this out.

exact same problem i had , and yes , i wired it to a constant 12v , as the scangauge switches off automatically once it stops getting a signal from the ecu etc...

Matt

strange that? As mine works fine from the OBD port

[16vmini]

I am having issues with my scan gauge and I need to change the wiring to to the obd socket, so that I have 12v for a longer period as it does not remember any trip information at the moment, so I am going to put a permanent 12volts to the obd socket from the leisure battery to try and sort this out.

exact same problem i had , and yes , i wired it to a constant 12v , as the scangauge switches off automatically once it stops getting a signal from the ecu etc...

Matt

strange that? As mine works fine from the OBD port

yes but i have hacked my wiring loom myself ! LOL .. so to start with i had no 12v feed ! :LOL

you got your loom modded properly ! LOL

Matt

[lloydy]

So looks like the gauge issue will be solved, after a few emails to Simon in which he i got some good quick advice. I'm going to use the T3 sensor for the gauge and fit it to this
http://www.brickwerks.co.uk/index.php?p ... t&Itemid=3" onclick="window.open(this.href);return false;
and sender and clip
http://www.brickwerks.co.uk/index.php?p ... t&Itemid=3" onclick="window.open(this.href);return false;
http://www.brickwerks.co.uk/index.php?p ... t&Itemid=3" onclick="window.open(this.href);return false;
its going to be fitted to the heater hose at the back of the head, just after the flange. a small 25mm bit of pipe needed for between flange and sender pipe as the heater hose is 16mm bar the last bit
http://www.brickwerks.co.uk/shop?page=s ... ning+piece" onclick="window.open(this.href);return false;,
Will then need to connect the gauge loom back up to the T3 gauge, by working out what wire does what on the 4 pin tdi sender and removing, or finding where in the loom they are spliced into the jx loom.

[pirate-pete]

According to wiring diagram the 4 pin TDI sensor is actually 2 senders in one unit. Pins 1 and 3 as per Ewans picture on page 2 of thread are one sensor feeding the ECU and pins 2 and 4 a second sensor feeding the dash module electronics (which in turn control the TDI gauge and warning light). What you are suggesting is to replace this part of the circuit with an original T3 sensor which is designed to match the T3 gauge and get a proper reading.

All makes perfect sense now.

If it helps identify the wiring I am looking at a PDF of a 1996 jetta TDI wiring diagram which shows following...
Pin 1 - brown/blue connected to brown/white sender earth
Pin 2 - brown/green earthed to engine block
Pin 3 - blue/brown to ecu
Pin 4 - yellow/red to wherever it is spliced into your JX loom.

[lloydy]

Cheers for the colours, I'll check and see if they match what I have.
Looks like I need pin 4 and another earth for the sender? Maybe pin 2? Or does the ecu part of the sender need that too?

[Simon Baxter]

For the sender you'll need the yellow/red wire to one connection and a brown to the other.
Dunno if I'm teaching grandma to suck eggs but on VW's brown is always earth.

[lloydy]

Always good to see it in print
Just had a word with my friendly loom installer and i should be able to join onto the original gauge loom either in the black box at the back of engine bay or unpeel the loom wrap and find the soldered and heatshrinked joints and cut into them there. So should be able to do it nice and tidily.
Funny thing is i'm getting a real itch to do another engine conversion, learnt so much doing this one

[T'Onion]

Funny thing is i'm getting a real itch to do another engine conversion, learnt so much doing this one

If your paying and fancy it ,I'll drop the heffa down , you can do me a 2.5tdi

[randolph57]

OK
Just to add my tupp'n hapeny just changed my thermostat again as when i replaced my 80 degree one i obviously had a dud as temp struggled to get above 60-now the reverse radiator hot ,guage now well above the LED and reading around 95 on my Ultra gauge.
Think i must have another dud although the operating range is 87-102 so i may be just stabilising higher than every one else (i like to be different).

when i had the 80 deg stat in max temp was 84 in all conditions.Off to Busfest and then France so may have to get a VW one locally (doubt they'll have one on the shelf tho')