Hi, I have a 1994 999cc uno ie start which seems to have a problem somewhere with the fuel system since I replaced the fuel tank. Driving round town I am lucky if I get 25 mpg out of it but driving at 60 mph in 5th gear I am getting close to 60 mpg. I have checked over the fuel system and there isn't any signs of leaking, also I have had the lambda sensor off and blew out the soot that had built up on it. The airflow temp sensor looks to be ok but how do test that it is working properly?
Any suggestions what else I could try?
Thanks.

mine does around 41miles to the gallon for city driving. We dont have highways here in malta so cant give you any fuel consumption figures for the motorway but Im sure I can get it close to 50-55mpg if I get 41 in the city!!

hmmm, mines over fueling at the mo, needs setting up. im getting about 14 to the gallon on good days! if i really boot it i can actually notice the fuel guage move :O

Dunc

Fuel Needle

Hi Dunk,

Is that on sharp bends and hills LOL.

Regards All,

Thanks for the welcome
Louie: 40 mph in second? I'm usually in fifth gear by the time I hit 40.
Dunc: 14 mpg OUCH!
the haynes manual suggests to check coolant temp sensor & airflow sensor, How do I test that these are working properly & where is the coolant temp sensor?
It seems odd that it started using more fuel after I changed the fuel tank but there is no sign of a leak anywhere.
Thanks.

Icestorm said:

Thanks for the welcome
Louie: 40 mph in second? I'm usually in fifth gear by the time I hit 40.

Click to expand...

I tend to miss 3Rd and 4Th gear LOL.

Icestorm said:

the haynes manual suggests to check coolant temp sensor & airflow sensor, How do I test that these are working properly & where is the coolant temp sensor?
It seems odd that it started using more fuel after I changed the fuel tank but there is no sign of a leak anywhere.
Thanks.

Click to expand...

Welcome to the mysterious Bosch SPI system LOL. Have you checked the adjustment of the accelerator cable?

EDIT2 - Shoot – What happened to this bit?

You may have damaged the Lambada sensor by removing it – they are really fragile (and expensive). On the SPI system these is a diagnostic socked.

If you get a tune guy with the right tools – they can hook up and (I think) tell you the problem.

Also Have you seen
https://www.fiatforum.com/showthread.php?t=25661&highlight=coolant looks helpful (not all posts relate to SPI moddle).

Kind regards,

PS How about an ECU reset? PS How about an ECU reset? (Edit don't look in Haynes reset isn’t there! - search this forum LOL)

Louie Bee said:

You may have damaged the Lambada sensor by removing it – they are really fragile (and expensive).

Click to expand...

I had been warned about the fragility of the sensor. It was removed & replaced V. carefully and does not seem to have been damaged, the car runs no differently than before I started unscrewing bits.
I had read the https://www.fiatforum.com/showthread...ghlight=coolant thread a couple of weeks ago but had forgotten about it (thanks for the link ). I'll reset the ecu & see if that makes any difference.
The other option of course is to try and drive everywhere at 60 mph
Thanks.

I've managed 48mpg from my 1108cc. That's doing constant 60-65 mph (motorway).

Worst I've got is low 30s, and that's with all city driving.

It's improved a lot since getting a new air box and hot air pipe.

Would not having the hot air pipe make a difference? the pipe is missing on my uno.

Possibly. The car would warm up quicker with it on. I can actually drive (albeit slowly) my Uno while it's warming, when before I couldn't. The previous air box basically had a non-working flap inside and so the hot air hole was always blocked.

I tend to have it on or off - just check the weather first. If it's a hot day, I take it off and on if it's winter-ish.

I find that as long as the flap within in the airbox is either working, or simply blocking the cold air feed, the car just runs better.

Re: Fuel consumption problem - UPDATE

Good news the fuel problem appears to be fixed. I did an ecu reset but at first this seemed to create a whole new problem, on tick over the revs would go from struggling to keep the engine turning over to revving really fast then back to struggling & nearly every time I braked it would stall. Nosing around under the bonnet I noticed that the hose on the vacuum advance unit had a split in it. After chopping the split end of the pipe off and refitting it, checking the accelerator cable adustment and another ecu reset it now appears to be working fine. Don't know what milage I'm getting about town yet but I'll let you know.
Thanks to everyone who replied with suggestions, I don't think I would have fixed it with just the Haynes book for ideas