Altezza Failed The Sva Test!

[jasear]

Well it had its test today and failed on emmissions, and something wrong with the speedo i.e. it showed 50 on the clock when it was doing 53, 40 when it was doing 44 e.t.c. is that a big problem?

It also failed on some depleted braking thing. Not sure exactly what that is but was told its a test of the brakes when the car is switched off??

Any advice would be greatly appreciated.

[aido]

Is it still on the standard wheels or have you changed them? Maybe the ratio is out and that's buggering up the speedo.... Can't remember if it was here I read it but I saw something that said most speedos overestimate by up to 10% so that you can't do the car company if you get done for speeding and your speedo said you were okay (ie it says you're doing 50 but you're really doing 55 etc...)

[jasear]

well it has the standard wheels. Im thinking that could it be something wrong with the speedo conversion unit they put in to convert from km to mph?

[altezzaz]

I think the speedo conversion is just a software change - and the fact that as you're going faster the difference gets smaller doesn't sound like the maths is wrong. Surprised at the brakes - these cars have the best oem brakes short of a porsche.

[ColinBarber]

What size are the tyres?

[jasear]

Well the wheels i think are either 17 or 16 inch. So what could be causing this problem then?

[ColinBarber]

If the tyres are the wrong size it could put the speedo out.

What are size of the tyres?

16" wheels should have 205/55 16

17" wheels should have 215/45 17

[jasear]

thing is I havent checked the size and the car is not with me so i cannot check right now. I think they're probably 17". but i will check that today and let you guys know.

[jasear]

Well it has 17" wheels.

Now the thing is i dont think its got anything to do with the wheels. Cause when the car is showing 60 it is actually doing 60, At 70 it shows 70, but as u slow down and do 50 it shows 50 on the speedo but its actually doing 51, then at 40 its actually doing 43, when it shows 30 its doing 36. If it was the wheels then as the speed increases the margin of error would also increase. But here we have an opposite situation which i really find very strange.

Could it be the conversion unit?

The guy who prepared my car for the sva says he has never come accross anything like this and finds it really strange.

he is going to try and put in a new unit and see how it goes.

Im really mystified.

[ColinBarber]

At 70 it shouldn't be showing 70 it should be around 73-79mph.

Could be the convertor. Maybe it's not detecting all the pulses, if you miss a pulse at lower speed it will make more of a difference than at high speed.

[jasear]

I assume by the connector you mean the conversion unit.

I think ure right cause what ure saying makes a lot of sense. Something like that would result in what is happening to my car.

but if u miss a pulse shouldnt it result in showing the speed being less?

[ColinBarber]

I assume by the connector you mean the conversion unit.

I said the convertor. Yes I mean the conversion unit :)

but if u miss a pulse shouldnt it result in showing the speed being less?

Isn't that what is happening? You said a reading of 30mph and the car is actually doing 36mph

[jasear]

lol!

ure right. I think thats it! must be something wrong with the unit or maybe the guy hasnt connected everything properly.

Saying that though, can you think of any other problem that could possibly cause this?

[ColinBarber]

A faulty speedo?

[jasear]

And if its a faulty speedo then what kind of expense am i looking at?

[SteveAudioX]

It will be the speed pulse converter.

My friends had his SVA done and the miles was slightly out, but they passed it on that they are not 100% accurate and never will be...

The brake thing, could it be because they need bleeding or something, or perhaps handbrake adj.

[jasear]

why did they fail my car then? sounds like double standards to me.

With the brake i think it could be the brake pads or something.

[ColinBarber]

why did they fail my car then? sounds like double standards to me.

I guess like the MOT it depends on the tester? Maybe there is a tolerance that your car is over because at 36mph your speedo is nearly 17% out

[SteveAudioX]

My mates Altezza was out... But his car is reading say 70mph and it's actully doing 63mph, they said it would of failed if it went the other way.

Say if the car is reading 70mph and actully doing 70+

[el_gencer]

Your speed thing sounds odd for the car to fail. I measured my speed with a gps and mine appears to be about 3mph out, and the same also applies on my friends vectra. But that could be the sat delay kicking in, however i did have around 20 sats connected to the gps so my readings were pretty spot on.

[ColinBarber]

UK speedo are fine to read over. Up to 10%. They cannot read under.

[SP33DY]

I had my Altezza SVA tested last month and the inspector told me the speedo was out of sink. After hearing what everyone is saying I think I might have heard wrong but I think he told me that my car was doing 63 when it showed 70. It was also failing on emmisions in both the SVA and MOT. On both occasions I had good guys who just let the car run for a while and it passed. I had also let the car warm up for half an hour after getting advise from SteveAudioX.

[ColinBarber]

Reading 70 when only doing 63 is okay. Jasear had a problem because his is reading under.

[SP33DY]

On a slightly different note could this difference in the MPH be the reason why some Altezza owners think there not get as many mile to the gallon. Does MPH affect miles travelled i.e. do we think were getting 300 miles to a full tank when we have really travelled more miles.

[SteveAudioX]

Thats a good point on the fuel economy thing, could also go with the standard IS 200 owners too.. :winky:

I thought you were a gold member