Welcome to Saabscene!

I drive a 2.3 lpt auto, with upgraded ecu, I can get around 24mpg on my daily commute, which is 8 miles of sub B roads.

On a run 35mpg is fairly easy to acheive.

 

I drive a standard 2.3 SE auto and get 22 or so driving around London in the rush hour. The Aero is supposed to be more economical driven at the same speed.

A few guesses:

Blocked air filter or pipework
Stuck injector
Collapsed catalytic convertor

These would affect performance too. Can you compare it with another Aero?

 

20021/2 Aero est, manual.

Last 6000 miles ave 29.6 MPG. this mostly involves a cold start, followed by eight miles empty urban roads,followed by a 12 hour gap & then repeat.

Hope this is of some help with your info gathering.

M.

 

Thanks for the replies so far. Looks like I'm not imagining a problem!

The only thing is, how to get it sorted out. Seeing as the local garage can't find a problem, the only thing I can think of is to take it up with Saab GB. But I can forsee lengthy arguments!

 

Originally posted by sgould:
[qb]I drive a standard 2.3 SE auto and get 22 or so driving around London in the rush hour. The Aero is supposed to be more economical driven at the same speed.

A few guesses:

Blocked air filter or pipework
Stuck injector
Collapsed catalytic convertor

These would affect performance too.  Can you compare it with another Aero? [/qb][/b]

Thanks for the guesses. But as the Saab Garage pointed out, if there was a serious problem with the engine then the computer should pick it up. The performance seems fine, not that I dare use it properly at the moment!

They also said they would expect a combined figure in late 20s/early 30s.

 

The computer only pick up things it can compare with other info it's getting. So if one sensor is giving a false reading and there are no other sensors to tell the computer otherwise, you won't get a fault alert with the "Check engine" light on.

I had a problem with the car stalling - nothing showed up on the computer at the dealer, I think That Cosmic-Blue 9-5 had a similar problem with no error codes coming up. I solved my problem by trial and error and replaced the crankshaft position sensor.

 

My 2002 Aero (250BHP) is averaging about 27 mpg on my daily 5 mile commute to and from work, rises to 34-35 mpg on a long motorway run and I have even seen close to 40 mpg if the boys in blue are out in force making me drive slower. Having said that if I drive like a total hooligan and hit the rev limiter in the first three gears around Devon's country lanes I have seen 13 mpg appear on the SID. Hope this helps you out

 

Typical driving for me gets around 27-28 to the gallon.

When towing with the racecar on the back & tyres in the rack (very aerodynamic) I get about 16-17mpg.

Mines manual, auto I would expect would be 2-4 mpg worse, but then I drive mine hard.

If the economy is as bad as you say you should only be getting 250 miles from a full tank. Can you check this from the journeys you have taken ?

If that really is the case (and the mpg figures you quote are not just what SID is telling you), and assuming the car is running well then I would be looking for a simple fuel leak.

Is there a smell of fuel anywhere ?

Jumping about a bit I know, but if the fuel is going into the engine, then it is either being burnt, in which case you'll be having lots of

, or its going down the exhaust pipe as unburnt fuel.

Have you tried giving it some

. If you did and it misfired then it could well be overfuelling.

A quick rolling road test with a gas analyser operated by someone knowing what they are doing should quickly identify what is happening based on CO and hydrocarbon levels.

Doing the tests in a static environment without load on the engine is just not as illuminating, I know - I've been struggling with different fuelling problems on the race car for 3 months. Now fixed though

 

A long shot, but carrera's post has jogged the memory.

If you are reading mpg off the SID and not working it out for yourself.... Is the SID set to USA units? If so, their gallons are about 5/6ths of UK gallons.

 

You could well be right, nice cheap fix too

 

Loads of useful information there thanks Carrera.

What the SID's showing matches up with the amount of fuel I'm having to put in. I just double checked and it is definitley set to the correct units.

Think I'll probably just have to go to Saab with all the information people have given and see if that helps them to identify the problem.

 

My 2000 Aero is a manual not an auto, but I have yet to get less than 31mpg on a tankful. More usually 33-35 and when I really tried to be extra economical, I got 39mpg on a long run.

I think this is exceptionally good, but if it only did 21mpg, I'd
A) want it fixed fast or
B) want another car

I'm sure your car should do better, don't accept the "they all do that, sir" from the dealer

 

I typically get in the mid-low 20's. But Nick Taliferro pointed out that Saabs get the best gas mileage on higher octane. I don't have that available in California so that explains it for me.

Cheers,
Dubbya

 

I have a 2000 Aero 9-5 with an auto box around town this means lots of stopping and starting in Birmingham road with traffic etc. I get about 21mpg as an average, this is going simply by the SID if I was to go by the fuel guage I would be filling up alot sooner probally equate to about 15mpg I guess, anyway I took it on a long motorway spell recently and this averaged at about 38mpg which is very good I thought was very good, I suppose when you stick in £20 like I do once a week after 50-60 miles the reserve light does come on but like I said I ignore this and go by the SID. I will be interested to know what is the real MPG around town for a 9-5 aero auto.

 

My MY04 95 Aero Estate is an automatic and barely run in at 3000 miles. I am getting about 24-25 mpg on a seven mile commute - may get better as the engine loosens up. My previous 2.0t automatic averaged 27-28 mpg on the same run.

 

Hello NPH 123, Clear your SID reading, go for a a trip of say about 40 miles up and down the motorway, and then see what your SID reads. Although this is not the most accurate way of doing it apart from filling the tank before and after the trip, it will give you some indication as to what the reading will be.

 

NPH123, I have a MY03 Aero manual box with 11300 miles on the clock. The SID2 reads as follows

average mpg 26.5
average speed 22mph mostly city
miles on trip 2,200

The consumption given seems far too high.

I ran and Audi A8 4.2 and got better than that.

The brakes don't have a slight bind that would increase rolling resistance?

 

Do the pre-face lift 4-speed autoboxes have the 'S' button??
If so, could this be faulty and maybe permantly engaged, if so, I suspect this would have an effect on consumption.

 

Originally posted by aeropilot:
[qb]Do the pre-face lift 4-speed autoboxes have the 'S' button??
If so, could this be faulty and maybe permantly engaged, if so, I suspect this would have an effect on consumption. [/qb][/b]

Yup!
But the dash telltale light should warn you it's on.
unless your taking full advantage of the function it shouldn't effect consumption much.

 

I tried clearing the SID the other day before a 100 mile round trip (on major roads and dual carriageways). Result - about 22mpg!

I suppose a slight brake bind could result in poor mpg, but I would have thought this would also affect the general performance, and on the rare occasion I've used this, it seems fine. But you could be onto something there.

My model does indeed have the Sport button and I'd considered that there may be a fault there, so tried switching it on and off and there's definitley a difference, so should be working fine.

I expected manufacturers' published figures to be a bit optimistic, but certainly not to this extent! From what everyone's said then it does look like a definite fault.

 

mis-adjusted brakes would also throw out a fair bit of brake dust or leave them on the rims. If clearing the SID had some affect then 1 of many things that could be out is also the oxygen sensor, possibly resulting in an incorrect fuel/air mixture, another thing to try is maybe a fuel injector cleaner (clutching at straws ) but i guess this wont be that important.

 

What about the tyre pressure? If it to low, it could cause a 10% decrease in fuel economy!

 

Thanks to everyone who's posted about this.

Had a long discussion with the Saab garage today. They're going to have it in for more in-depth testing for a couple of days next week and also compare the computer readouts with a couple of identical models they've got. So hopefully that should get to the root of the problem (maybe!).

 

That fuel consumption definitely seems excessive.I have a 03 Aero saloon auto with 7,000 miles on it and get 20-22 mpg in town.On a long run I can get 30-34mpg.This is taken from the computer,but seems reasonably accurate.

Let us know what they find.

 

I've got an auto Aero with Abbott ECU and rear box. On my daily run from Norwich to Cambridge I get a whisker under 30 mpg. I think something is wrong with your car, I've never managed to average less than 23 even flogging it in France at 100+.