MGP - ECU Tweak?

[Yellow Bentines]

Just a quick question.

Is there any way you can re-program the ECU to give better MPG?

I'm trying to drive as economically as possible, but given my nearest garage is selling standard unleaded at £1.39.9 a litre it's getting to really hit hard.

I'm looking into a possible LPG conversion too, anyone had any success stories converting a 9000?

[Max Headroom]

Hello Yellow Bentines and a big welcome to the forum. 

I can't advise you myself, but I'm sure someone will be along soon that can shed some light on this

[Kev_Mc]

There was a chap on the old forum (Saabscene) called Keith - username Gassy, who converted his 2.3 9000. Sure he did a lot of miles in that with no problems, though I can't remember the manufacturer of the LPG kit.

What 9000 have you got? If it's a turbo, and you were to go for LPG, make sure you go with an installer with experience of fitting LPG to Saab turbos. I got my fingers burnt converting an old 9-5 to LPG. Would have been cheaper buying a modified Aero and driving with my foot to the floor everywhere.

[Audax]

If you convert a 9000 to gas it will take a while to start paying you back, gas conversions seem to run to about £1500 which lets face it is more than the value of most 9000's out there, lpg might be a bit more than half the cost of petrol but it will only do something like 80% of the mileage so if you're looking at an lpg conversion will not become cost neutral until you have done at least 15k after the conversion, after another 5000 miles you'd be looking at having saved potentially £500. I'd be having a think about replacing the 9000 with a more fuel efficient car either diesel or petrol rather than gas converting it.

As for mapping the ecu for better MPG, it's possible but you risk running the engine lean, if you do that then you risk blowing the engine, you won't be looking at a gain of anything more than 10% and I really think you'd be risking more than it is worth.

[Yellow Bentines]

Bummer, sounds like I'm best just sticking with what I've got. I really don't want to part with it though, It's such a good car.

Thanks to all those who replied.

[sgould]

If you think about it, power and economy are the same thing!  Well, up to a point.

What you are looking at is improving efficiency.  Getting more energy from the fuel you are burning.  So you need to make the engine efficient and then drive with less throttle.

[Audax]

You may see an improvement in economy by making sure your tyres are properly inflated (try around 36psi), changing the air filter, putting new plugs in. Also you may see an improvement if you replace the lambda sensor but then again you may not!

[David]

Not sure which model you have but.....

Disconnect the battery for 1/2 hour then reconnect. The ECU will have lost its 'memory' and will start over adapting to your driving style.
Reset the readout which gives you an average figure, though this will take time to setttle to a figure, espcially if you reset it whist doing town driving.
Manual gives far better mpg than autos.
Full service and new filters are a must. Having a good independent specialist to ensure everything is as it should be  is always a bonus - I use JamSAAB.
An effiicent turbo helps.

When set up and maintained correctly a 9000 is an economical car.
I travelled over 250 miles this weekend (Bristol/Coventry/Basingstoike/Bristol) on a mix of motorwayand A roads at a steady 50-60mph and got an average of 43mpg. Not exactly an exciting speed I know, but I was in no rush. Took the car to Sweden last year and even with some serious 'spirited' driving over 2,500 miles we got 38mpg. I know others have also achieved good mpg figures.