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Unusually High Fuel Consuption

RT33

By RT33,
in Engines & Forced Induction

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RT33 Collaborator

RT33

Posted
Posted

i had my engine rebuilt and now fuel consuption is about 18L/100kms and thats just cruising around. i also stall for no reason every now and again. people say the satlling is from the bov. its stmo venting, but i've had the bov for 3 years without stalling.

mods are fmic, bov, pod, exhaust

thanks!

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Cubes Grand Master

Cubes

Posted
Posted

Bad fuel consumption can be related to the head work.

I had Chris Milton Engineering here in Adelaide do the work on my head. I wasn't able to find a more highly regarded workshop here in SA, even though they did charge a little more I feel it was worth it.

All though you do have a stalling issue so there may be a little gremlin lurking.

Do the usual. Check afr's, o2 sensor, afm and ensure injectors are clean.

Cubes Grand Master

Cubes

Posted
Posted
the head was high flowed before the rebuild, so thats not the problem.

could installing a 500hp walbro pump really be the cause for the unusually high consumption if there is no aftermarket ecu???

Porting (or as you call highflow) heads can result in poor economy.....

Smooth flowing heads that have been tidied up is whats needed for a streeter, not something that has been ported out to all buggery. But I do doubt the workshop did anything more than a simple tidy up as lots of headwork costs lots and lots of $$.

And no.. fuel pump won't make you use more petrol.

as I said previously...

Do the usual. Check afr's, o2 sensor, afm and ensure injectors are clean.

I had an issue where all of a sudden fuel economy dropped to 350km's to a tank. Turned out to be the injectors. Replaced them and all was dandy again.

HRthirtyone Rising Star

HRthirtyone

Posted
Posted

maybe something has happened to the fuel delivery system with the higher pressure from the new pump. Its either that or its a SENSOR, so

-as above, could be the oxygen sensor (in dump pipe),

-check airflow metre, clean it with non residual contact cleaner/brake cleaner

-may need to have your injectors flowed/tested etc, only costs around $100

-check the fuel lines, trace them back under the car, for leakage.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Porting (or as you call highflow) heads can result in poor economy.....

Smooth flowing heads that have been tidied up is whats needed for a streeter, not something that has been ported out to all buggery. But I do doubt the workshop did anything more than a simple tidy up as lots of headwork costs lots and lots of $$.

And no.. fuel pump won't make you use more petrol.

as I said previously...

I had an issue where all of a sudden fuel economy dropped to 350km's to a tank. Turned out to be the injectors. Replaced them and all was dandy again.

agreed

prelude_1976 Explorer

prelude_1976

Posted
Posted

Did u touch any piping recently?

I swapped over my M's filter to Apexi's (3weeks ago) and forgot to tighten (or came loose from heat?) the clamps from AFM to turbo, subsequently caused 20L/100KMs and stalling problems, due to ecu overfuelling?

Anyways tightened every clamp and poof, no stalling .

The engine would hunt between 900rpm ans 1200rpm, then go down to 300, then stall ONLY when it was hot, and it felt so sluggish, like a cold start morning.

RT33 Collaborator

RT33

Posted
  • Author
Posted

i put the fmic on bu it had the same problems. so shouldn't be piping, but i'll check it out. also it used to idle at around 1200 and after about 600kms it idled at 750 but it goes up and down a bit.

i checked my bov to see if it opening up and it was fine. a friend told me i could be the wastgate not staying shut. could that be it? my turbo is leaking a bit from the seals. i had to leave it on till i got my hands on another one. im replacing it tomorrow so i hope it helps

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