Alfa 156 JTD new owner - few questions....

[chrisga]

Hi everyone, as I said in the other post we just bought a 156 Veloce 2.4JTD stationwagon and are currently loving it.
However we have a couple of quick questions, not having been alfa owners previously...

The onboard computer thingy and fuel consumption - how accurate is this and is there any way it could be incorrectly calibrated? What sort of figures do you guys get typically if driving normally?
Should a 2.4JTD 52 plate have an undertray of any sort? I had heard they were notorious for catching on speed bumps and the like but our car doesnt appear to have anything like this.
Is there any way of stopping the stupid grin when you drive it?

[RicksAlfas]

Good choice. I loved mine!

I never had any reason to doubt my on board computer, but never measured it "in real life". It used to show 35'ish knocking round town and 45'ish on a motorway run. They can get put out of synch by remaps, but then they tend to read optimistically.

They should have an undertray, but many have fallen by the wayside. I personally wouldn't stress about it.

[sjg]

Mine is between 5 and 10 mpg optimistic. It'll do high 40s on a mainly motoway tank, lowest was 35mpg at a fast cruise on the autoroute, 4-up with a roofbox fitted.

[chrisga]

Ah thanks guys, ours is reading what i would describe as somewhat pessimistically, i.e. you could be doing 60 in a nsl say with neutral throttle (i.e. enough to maintain speed but not accelerate) along the flat and the actual mpg figure on the little screen (not a calculated one) seems to be down at about 30ish when I would expect a little more if it was like the figures you guys give. It said a range of 365 when we filled up with 55 litres too. Which would indicate it thinks we average about 26.5mpg. I know its not the beall and end all and isnt really a prob, just wondering if it really could be that low.
We know how many litres we put in and reset the trip so will do a full tank and see how far out it is when it says its empty.
Cheers for the replies everyone!

[bint]

Yup, our undertray scrapes a bit, but it's better than scraping the sump!

[V6Alfisti]

The plastic undertrays are very prone to damage, most are hanging down or thrown out by servicing garage.

They offer little protection to the sump, so most people opt to leave it off or buy the Zeatek (supplied by Autodelta now) Alloy Undertray, but costly at around £130!

Alfisti.net sell them as well

http://shop.alfisti.net/Tuning-Styling/Alfa-156/Mo...

Edited by V6Alfisti on Monday 2nd March 18:41

[chrisga]

Thanks everyone for your replies. I think I have figured out why the car we bought seems so far out on the fuel consupmtion figures it displays on the computer thingy. I did a trip of a known distance yesterday (home to work about 18 miles) and the trip B part of the computer read it as only 11 miles. Where does the onboard computer get its distance information from. Hopefully not the same place as the odometer in the speedo.......
And is there a way to reset it?

[RicksAlfas]

Did you stop on your journey? I seem to remember TripB is just that - a trip meter and zeroes itself after a short time.

Try resetting the whole trip computer - hold the end of the stalk in for a few seconds on Trip A and then go from there. You could zero the odometer at the same time, then do a known journey, or GPS it.

[Dave Brand]

chrisga said:

Where does the onboard computer get its distance information from. Hopefully not the same place as the odometer in the speedo.......
And is there a way to reset it?

I would assume the computer gets its data from the same sensor as the odometer - on my 147 the two figures match exactly.

If it's the same as the 147, to reset trip B just hold the button on the end of the stalk down with any trip B reading & it will reset. Same goes for trip A, but resetting trip A also resets trip B!

The range figure appears to be calculated on a limited set of recent data, not overall consumption. If you've been doing a lot of short runs around town the indicated range will be much less than you'd expect - 20 or so motorway miles later the range indicated can be more than when you left home!

[chrisga]

RicksAlfas said:

Did you stop on your journey? I seem to remember TripB is just that - a trip meter and zeroes itself after a short time.

Try resetting the whole trip computer - hold the end of the stalk in for a few seconds on Trip A and then go from there. You could zero the odometer at the same time, then do a known journey, or GPS it.

Did stop, but only at junctions etc, didnt turn the engine off.
Tried it again tonight and the trip computer is definitely reading different mileage to the main odometer in the speedo.
I figured out how to reset the trip computer with the set button on the end of the stalk, but is there anyway to reset the whole car's memory kind of a thing. Do you guys know who might know where the trip computer gets its information from? I am convinced it is reading differently. If we disconnected the battery does that reset the ECU? If so does it need to be disconnected for a certain amount of time, and is there any risk of anything going wrong if I do that?

Thanks again guys, hope you dont think Im being a pain asking so many questions....

[RicksAlfas]

From what I can gather this problem can occur if the car has had a flat battery in the past. What is happening is the trip computer is working in kilometres - so it says 10 miles but it thinks it's 10 kilometres. This then screws up the mpg figures. If you zero your computer and your odometer and drive for 160 miles (on the odo) your computer will show 100. Or get a distance on your trip computer e.g. 10 miles and change the units to kilometres - it will still say 10!

Unfortunately it seems the only way you can get this sorted is to hook it up to Alfa Examiner. A decent alfa specialist will have one. Not sure whereabouts you are but if you let me know I can look in the directory and see who is nearby.

[chrisga]

Ah thanks Rick, I was thinking along those lines as home to work is about 18 miles and it read about 11 on the trip computer, which i had a niggling suspicion was about 5/8 out but I didnt want to say that for fear of sounding stupid...
Yes, i do believe the previous owner highlighted the new battery to us, so I am guessing what you say is bang on the money. Thanks for finding out.
We are near to Warwick, so if you could find out the nearest place we could take it to sort it that would be great. Oh and if anyone knows any people that are alfa specialists in this area that would be great. Have no problem taking it to a non-dealer place if they are recommended by others.

Chris

Edited by chrisga on Friday 6th March 08:09

[RicksAlfas]

My geography around there is a bit poor but you could try:
WAD 01902 401711
NJS 01386 555523
Intaservices 0116 2510899

Just check they have Alfa Examiner before you go.
Incidentally the odometer is correct, so it might not be worth a special trip just for this sorting out. Most places have a minimum charge to plug into the Examiner so it might be better waiting until you need a service. Hope you get it sorted!

[chrisga]

If we change it to read km (not sur eif thats possible) that should make the km/litre reading for fuel consumption correct then shouldnt it?

[Dave Brand]

RicksAlfas said:

What is happening is the trip computer is working in kilometres - so it says 10 miles but it thinks it's 10 kilometres. This then screws up the mpg figures. If you zero your computer and your odometer and drive for 160 miles (on the odo) your computer will show 100.

If the trip computer's working in km & the odometer's working in miles, the trip computer should be giving the higher figure!

[RicksAlfas]

Dave Brand said:

RicksAlfas said:

What is happening is the trip computer is working in kilometres - so it says 10 miles but it thinks it's 10 kilometres. This then screws up the mpg figures. If you zero your computer and your odometer and drive for 160 miles (on the odo) your computer will show 100.

If the trip computer's working in km & the odometer's working in miles, the trip computer should be giving the higher figure!

I agree, but from other examples of this happening it doesn't seem to! The computer seems to take the miles from the odo (say 160), but treats them as if they were kilometres and displays them as miles! So 160 on the odo would be 100 on the computer... Remember this is the same computer which spells October with a K and can't cope with leap years so anything is possible!

[velocemitch]

My GTA started doing this for no apparent reason. I was told by the dealers that the only cure was a new speedo head. I decided not to bother as it was expensive and I would have had a Zero mileage reading which might raise suspicions when I came to sell.

Edited by velocemitch on Tuesday 10th March 19:12