Common causes for POOR fuel consumption?

[fesuvious]

Hi.
The missus\' RX7 (F3DS) has horrendous fuel consumption.

Its been serviced and is still just as bad (@10mpg). Are there any \'common causes\' of this? Im thinking maybe an injector gone bad but as I am not overly familiar with the RX\'s I thought id ask here first....

Are there any known first ports of call for diagnosing this?

[S3TH]

Leaking/cracked fuel rail? (Potentially quite dangerous!) Can you smell fuel?
Running rich? Have you got an Apexi on that?
Heavy foot? :Giggle

[fesuvious]

No smell of fuel...

Is a Jap import running what certainly looks like ( and is labelled up as such ) a standard ecu.

Heavy right foot? I wish, its driven just \'normally\' No thrashing, no high revving...

But its giving @10mpg

oh, its flooded 3 times recently..........

[logicalChimp]

Have you had a compression check done?

I\'ve heard that poor compression can affect fuel consumption.  The fact that the engine is flooding would also indicate that you may have poor compression (or so i have read)

[DC-TYPER]

mate that is bad, my missus gets over 20! round town too!

[m4drx]

i get 10-12 MPG but i have decat filters etc (which isnt the reason i would say) and an apexi running on base map.

Absolutely awful on fuel.

oh and i have 8 bar comression engine - basically rebuilt.

[trotter]

"Common causes for POOR fuel consumption?"

ermmm, owning and driving an FD3?? :Thumbsup!

Sorry, that wasn\'t too helpful, but couldn\'t help myself! :rollin


In all seriousness, i\'m averaging around 13-14mpg when driving round town - but 10 does sound mighty low even for one of these thirsty fdukers.

Has it been mapped recently? How does the exhaust smell when the engine is under load? Before I got mine mapped post-rebuild she was running horrendously rich - have a wee sniff at the exhaust and see how badly it stinks of fuel. Sounds stupid I know but if the engine isn\'t mapped right she\'ll be p!ssing the fuel straight out the back!!

[SmbFD3S]

Could also be a knackered O2 sensor....Have you got an Apexi PFC to see what the voltage readings are on the O2 Sensor
 
Like M4DRX says, i\'m also running on Apexi base map and still get around 16 althought the air/fuel gauge reads extremely rich running all the time so wil be better when mapped... Also, mine stinks the cab out of fuel when on WOT lol !!!!!

[trotter]

Could also be a knackered O2 sensor....Have you got an Apexi PFC to see what the voltage readings are on the O2 Sensor
 
Like M4DRX says, i\'m also running on Apexi base map and still get around 16 althought the air/fuel gauge reads extremely rich running all the time so wil be better when mapped... Also, mine stinks the cab out of fuel when on WOT lol !!!!!

mmm, "Magic Tree Unleaded Fragrance" :Party

[Archbish]

are you driving everywhere in first gear?  or even reverse?  is it realllllllly hilly where you are, so by driving for 3 miles, you\'ve actually driven 4?  Does it have a bodykit made of granite? Or lead?Are you using metric or empirical miles?  US or UK Gallons?  are you driving with the lights on, rear window heater on, hot air on full, winding the windows up and down with the doors and boot open?  Is the drain plug in the fuel tank OK?  Which town are you driving round?  If it\'s beirut, then just be happy to have arrived!!  If it\'s Basra, it\'s probably down to racing and driving erratically to avoid heavy artillery (or the armour plating on the FD).  If it\'s milton keynes, it may be down to the 30,000 roundabouts you have to negociate between the motorway and the stupid snowdome.

[S3TH]

:Giggle:Giggle:Giggle... Joker!

[fesuvious]

:rollin at post above

anyway. Update (albeit not much of one )

Stuck an exhaust gas analyser on her and all is well at idle. If anything a little weak.

Not running an Apexi, TBH I know very little about RX7\'s and their engine management options....

Are there any tips for diagnosis? The car went on a fault code reader a couple of weeks ago and no fault codes were present...?

At the moment Im thinking leaking injector (or 2?) or a problem with the ECU. Are the standard ecu\'s mappable? Could someone have tampered with it in the past?

The fuel usage seems to be horrific at cold and just awful when warm.

Anyone know a really good diagnostic specialist close to Birmingham ( Solihull ). Would rather work on recommendation from someone........