fuel gauge reading, 740

driftwood · Post by **driftwood** » 28 Apr 2004, 15:57

Ty in advance!! I have just bought a 96 740 2l auto estate. The fuel gauge erratic, full, half full, empty etc. Any advice very welcome as I have no idea how much fuel in tank, how much i am using etc!!! how many miles on short runs before i run out from a tenner of petrol even???? I dont want to run out as i have a 1 yr old son in car with me but i can not afford to constantly fill up

Pleas advise me, any feed-back greatly appreciated,
Steve

Volvord · Post by **Volvord** » 29 Apr 2004, 18:08

There is some documentation on this. Check out :

http://www.brickboard.com/FAQ/700-900/E ... Fluctuates

Hope that helps

driftwood68 · Post by **driftwood68** » 30 Apr 2004, 16:51

TY for the reply, Can anyone please tell me roughly how many mpg to expect from 740 2l automatic???? used on short runs mainly

petershen1984 · Post by **petershen1984** » 01 May 2004, 02:20

I've calculated my fuel economy over a period of three fillups, here are my averages.

14.30 mpg
7.03 gallons per 100 miles

Volvord · Post by **Volvord** » 02 May 2004, 08:25

WOW Peter, you are either running rich or drive hard. My 740TI which I have had for 14 years gets an average of 18+ MPG in the city and 28 MPG on the highway. My 350HP V8 Volvo gets 12 MPG in the city and 26 on the highway.

petershen1984 · Post by **petershen1984** » 02 May 2004, 10:30

hahaha yeah, thanks

The Answer is, I drive hard for a car that barely accelerates. The B200E, mechanically injected, SOHC, (110hp / 110 ft-lb) is very underpowered - and takes longer to torque up to higher rpms before shifting. The 740 weighs like 1800 kgs!

Recently, my mechanic personally drove my car and fixed my malajusted kickdown and shifting. Prior to this, I didn't know any better - It shifted early and at the wrong speeds (4th gear below 60 km/h?!) heh. so my numbers may change this time round.

http://www.mx5oc.co.uk/mx5forum/topic.a ... IC_ID=4858

running rich will use more fuel thus giving poorer fuel economy as Rich means more fuel than air. Runnning lean you will use less fuel and get much better fuel economy. HOWEVER too lean and you will melt your engine and too rich you will soot everything up. MX5's/Roadsters all run slightly on the rich side to prevent engine damage.

You will also find that if something does go wrong with your car that the ecu will automatically makes it run rich to help prevent engine damage.

If your running rich you will notice black smoke from the exhaust and the plugs will have a black sooty coating on them, If running lean then you may experience detonation and overheating, the plugs will appear glazed and very white looking.

Wow, I'll check for running rich, but I'm not bellowing black smoke as described above. Or maybe my car is not burning all of the Premium fuel I've been feeding it (I've heard some detonation before. Time to down-grade!)

petershen1984 · Post by **petershen1984** » 03 May 2004, 07:49

Wow, premium gas was too lean (and thus a waste) for my vehicle - I downgraded to 95 RON and the exhaust temperature feels a bit warmer than not at all...

I have to check my cams, something doesn't feel right with acceleration - the engine feels as though it is tired after hard accelerations. Oil last changed 2500-3000 km ago.. It sure as hell is bothering me!!

ozzimark · Post by **ozzimark** » 31 May 2004, 14:43

with my '85 740 gle, i get between 19-23mpg, mostly kinda country driving (think lots of stop signs). although i drive it kinda hard being 18 and all

petershen1984 · Post by **petershen1984** » 02 Jun 2004, 10:28

I should do a more accurate measurement - my average measurements were done based on odometer readings between fillups - which includes warm up time, stopped traffic...