12 mpg cruising in T350 - what's going on?
Discussion
http://www.pistonheads.co.uk/gassing/topic.asp?h=0...
more details (moaning) in above thread. general question is - I used to get 25 to 30 mpg and thesedays I get half that, with the lowest whole tank average being 3-4mpg (31 miles on a full tank).
Note - this is not just a dodgy fuel guage this is real full to full measurements on actual fuel replaced into the tank.
otherwise runs like a dream and as powerful as ever (detroyed a Noble M12 GTO and was nothing in it between a red rose Sag on the last tradck day attended).
anyone had similar issues?
more details (moaning) in above thread. general question is - I used to get 25 to 30 mpg and thesedays I get half that, with the lowest whole tank average being 3-4mpg (31 miles on a full tank).
Note - this is not just a dodgy fuel guage this is real full to full measurements on actual fuel replaced into the tank.
otherwise runs like a dream and as powerful as ever (detroyed a Noble M12 GTO and was nothing in it between a red rose Sag on the last tradck day attended).
anyone had similar issues?
Perished fuel pipe from tank to pump?
Any petrol smells ?
I used to the odd whiff of fuel and pipes were a disgrace
Now never any smell with new marine grade pipes
Would have thought youd nice such a big leak
And if it was going into the engine it would run terribly
Any other effects...backfire through air box on starting for example?
What i dont get is if it was a leak, why would driving style effect the rate of loss?
Any petrol smells ?
I used to the odd whiff of fuel and pipes were a disgrace
Now never any smell with new marine grade pipes
Would have thought youd nice such a big leak
And if it was going into the engine it would run terribly
Any other effects...backfire through air box on starting for example?
What i dont get is if it was a leak, why would driving style effect the rate of loss?
thanks guys, all very sensible advice there.
This is what I was thinking myself - it HAS to still be a leak somewhere (since that much extra fuel would certainly cause some other negative effect in the combustion).
I'd be damned if I can find where it is though and what really doesnt make sense is that leaking that much fuel certainly would leave some sort of visible trace (or at least be able to smell it) and I cant!
For reference guys, what sort of mpg would you expect out of a long motorway cruise (or full tank, mileage-wise)?
thanks again
This is what I was thinking myself - it HAS to still be a leak somewhere (since that much extra fuel would certainly cause some other negative effect in the combustion).
I'd be damned if I can find where it is though and what really doesnt make sense is that leaking that much fuel certainly would leave some sort of visible trace (or at least be able to smell it) and I cant!
For reference guys, what sort of mpg would you expect out of a long motorway cruise (or full tank, mileage-wise)?
thanks again
...and on a slightly different note - does anyone have advice on connecting to the ECU?
Was trying to connect to diagnose the fuelling issue. I tried a 3-pin to serial lead but the only 3-pin I could find did on the loom did not communicate. My car also has an OBD-style on the passenger side (mid 2003) which my mate's tamora does not (his works through the 3-pin).
However connecting through the OBD didnt work either. (Does anyone know if it uses high speed or low speed can bus?).
However somehow the car wont even fire now - ive obviously disturbed wiring somewhere (!) It cranks but does not fire, and I cant hear the fuel pump priming any more. Have I done something obvious? I did disconnect a 5 -pin connector near the steering column but reconnected it again now. Could I have disabled the immobiliser by doing something like this?
Was trying to connect to diagnose the fuelling issue. I tried a 3-pin to serial lead but the only 3-pin I could find did on the loom did not communicate. My car also has an OBD-style on the passenger side (mid 2003) which my mate's tamora does not (his works through the 3-pin).
However connecting through the OBD didnt work either. (Does anyone know if it uses high speed or low speed can bus?).
However somehow the car wont even fire now - ive obviously disturbed wiring somewhere (!) It cranks but does not fire, and I cant hear the fuel pump priming any more. Have I done something obvious? I did disconnect a 5 -pin connector near the steering column but reconnected it again now. Could I have disabled the immobiliser by doing something like this?
update on this - looking likely to be a faulty lamda sensor - will let you know once Ive changed it! For ref, I used to get 250 miles out of a full tank on a long run. The T350 seemed particlularly efficient at high speeds relative to other cars Ive owned - i put it down to a particularly good aerodynamic shape (and therefore lower drag).
On a different note, in messing about with the TVR diagnostic programme that i could never get to work, ive created a bigger problem. The car will crank, but not fire.
Furher investigation with a multimeter shows that there's no power to the fuel pump relay or fuse during cranking/key on.
What would cause this? Does anyone know if the immobiliser can prevent fuelling? (normally you dont even crank if the immonbiliser is being stubborn). Is the fuel pump hard wired to the ignition or controlled via the ECU? (Im starting to get paranoid that I have somehow damaged the ECU itself)
On a different note, in messing about with the TVR diagnostic programme that i could never get to work, ive created a bigger problem. The car will crank, but not fire.
Furher investigation with a multimeter shows that there's no power to the fuel pump relay or fuse during cranking/key on.
What would cause this? Does anyone know if the immobiliser can prevent fuelling? (normally you dont even crank if the immonbiliser is being stubborn). Is the fuel pump hard wired to the ignition or controlled via the ECU? (Im starting to get paranoid that I have somehow damaged the ECU itself)
if anyone is still reading - or has similar issues in the future - the solution to the non-start turned out to be the fuel cut off valve under the passenger side dash. Somehow in rooting around for the ECU connection, Id disturbed the connection to that.
So the car now starts again, although still not managed to connect to the ECU. Im pretty sure mine is one of the rare few that connects via the OBD socket but getting it to to communicate is a nightmare.
Oh, and the dash has decided to go haywire too (powers up,indicator and shift lights work, but rev counter and LCD screen do not work).
im chasing myself round in circles here!
So the car now starts again, although still not managed to connect to the ECU. Im pretty sure mine is one of the rare few that connects via the OBD socket but getting it to to communicate is a nightmare.
Oh, and the dash has decided to go haywire too (powers up,indicator and shift lights work, but rev counter and LCD screen do not work).
im chasing myself round in circles here!
Could it possibly be down to different driving styles??
Even on the motorway, when a slower car moves out of the way, I like to give it some. As opposed to slowly speed up or keep a steady speed...
It's not for the speed or acceleration, merely for the noise it makes. Can't help it but she sounds too good
Even on the motorway, when a slower car moves out of the way, I like to give it some. As opposed to slowly speed up or keep a steady speed...
It's not for the speed or acceleration, merely for the noise it makes. Can't help it but she sounds too good
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