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SnowmanV8 · Dec 14, 2013

I know my V8 efi is over fueling I Will be checking injectors tomorrow. What else should I examine. It only happens under full throttle and going up hills.

jacksta · Dec 14, 2013

can you try putting less in it?

SnowmanV8 · Dec 15, 2013

Its over fueling not over full.

doz · Dec 15, 2013

Leaded right foot?

SnowmanV8 · Dec 15, 2013

I think I Will rewrite the original post.

jamesmartin · Dec 15, 2013

SnowmanV8 said:
I think I Will rewrite the original post.

how do you know its over fueling is it worse when hot than cold

SnowmanV8 · Dec 15, 2013

jamesmartin said:
how do you know its over fueling is it worse when hot than cold

Its been diagnosed by a mechanic. Yes worse when hot

classic kev · Dec 15, 2013

SnowmanV8 said:
I know my V8 efi is over fueling I Will be checking injectors tomorrow. What else should I examine. It only happens under full throttle and going up hills.

I have to say I really don't understand this. At full throttle how can it be overfuelling? and how can you measure it?

The thing is this, the injectors are triggered by the coil and the injector pulse is controlled by the ecu working from a fixed map. Even with cats, the 14CUX ECU ignores lambda at WOT as precise fuel metering and control isn't needed so it basically sees a condition that says dump fuel in as fast as possible.

zen · Dec 15, 2013

why does mechanic say this??
unless you leaving a black trail of smoke like on full choke (carby like) and plugs come out damp and black or car has been run up on dyno with o2 sensor up exhaust how is he going to know?

but things that could upset fueling not are..
.
blocked air filter.....this will make run rich..but wont burn more fuel
dodgy fuel regulator..this could make it burn more fuel..but more than likely all the time.

Spunka · Dec 15, 2013

Sounds more like struggling to get fuel when it needs it to me

SnowmanV8 · Dec 15, 2013

classic kev said:
I have to say I really don't understand this. At full throttle how can it be overfuelling? and how can you measure it?

The thing is this, the injectors are triggered by the coil and the injector pulse is controlled by the ecu working from a fixed map. Even with cats, the 14CUX ECU ignores lambda at WOT as precise fuel metering and control isn't needed so it basically sees a condition that says dump fuel in as fast as possible.

zen said:
why does mechanic say this??
unless you leaving a black trail of smoke like on full choke (carby like) and plugs come out damp and black or car has been run up on dyno with o2 sensor up exhaust how is he going to know?

but things that could upset fueling not are..
.
blocked air filter.....this will make run rich..but wont burn more fuel
dodgy fuel regulator..this could make it burn more fuel..but more than likely all the time.

It smells of fuel when stood near it or if you are stopped with window open. New exhaust is thick black inside after around 1200 miles max!

Spunka said:
Sounds more like struggling to get fuel when it needs it to me

I would have said so but all the overfuelling signs are there and 2 mechanics when presented with the evidence say over fuelling! I would like to say it's the fuel pump in tanks but I would rather not mess with that untill I rule out cheaper options as cash is tight!

jamesmartin · Dec 15, 2013

SnowmanV8 said:
It smells of fuel when stood near it or if you are stopped with window open. New exhaust is thick black inside after around 1200 miles max!

I would have said so but all the overfuelling signs are there and 2 mechanics when presented with the evidence say over fuelling! I would like to say it's the fuel pump in tanks but I would rather not mess with that untill I rule out cheaper options as cash is tight!

over fueling is unlikely to be fuel pump more regulator on the injector rail injectors or faulty temp sensor

fanatic · Dec 15, 2013

jamesmartin said:
over fueling is unlikely to be fuel pump more regulator on the injector rail injectors or faulty temp sensor

Of which the ecu temp sensors are notorious

SnowmanV8 · Dec 15, 2013

fanatic said:
Of which the ecu temp sensors are notorious

Is that the one you told me to change? Be stripping down injectors and starter tomorrow to test it all then trying to get it alive for the plains by sunday!

zen · Dec 15, 2013

jamesmartin said:
over fueling is unlikely to be fuel pump more regulator on the injector rail injectors or faulty temp sensor

forgot about the temp sensor..good point..

SnowmanV8 · Dec 15, 2013

Changed Temp sensor just checked a diagram. Injectors and fuel regulator tomorrow then go from there with her! Any-one local got a V8 starter?

Spunka · Dec 15, 2013

Is the Ecu brainy enough to sense over fueling, bring a light on and reduce power

Ive never worked on one , asking out of interest

jamesmartin · Dec 15, 2013

Spunka said:
Is the Ecu brainy enough to sense over fueling, bring a light on and reduce power

Ive never worked on one , asking out of interest

the only fuel tweaking is via lambda sensor and even then you dont know if its right or wrong

jamesmartin · Dec 15, 2013

injectors can be checked bu using 8 same size containers on for each injector and crank engine ,if theres an injector fault its unlikely all of them so if different amounts collected it tells you something

SnowmanV8 · Dec 15, 2013

No idea! Just gutless uphill and with boot down! Shame as it is nice when running "normal" Does get worse when it does it while hot!

jamesmartin said:
injectors can be checked bu using 8 same size containers on for each injector and crank engine ,if theres an injector fault its unlikely all of them so if different amounts collected it tells you something

Right so just unplug one at a time and crank it into a pot, Mark and repeat?

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