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Poor fuel consumption

freddofrog said:
I wish I knew, but I don't :unsure:

I've checked some more on tyre type, apparently the A rating are only about 2 mpg better than the E rating. Your's are C rating btw.

I suppose it all adds up though, let's say 1 mpg each for

A. valve clearances
B. tyre brand
C. tyre pressure
D. EGR (not one on my car)
E. O2 sensor (but IMO it either works or it doesn't, but I'm open to refs that show age can make a difference to mpg)
F. carbon build up (IMO the biggest factor of the lot, and I reckon that cleaning additives in fuel can help this)

while we're at it, you could also add the MAF sensor into the mix (probably much more than the O2 sensor)

I do wonder why you sold the previous car though LOL
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Yes I suppose it does all add up.

I sold the other car because I was broke financially. I have been unemployed a long time and cannot get a job, apart from tutoring students during the winter months.

I may have to sell the one I have now if I don't get some income soon. This is why I am so obsessed with fuel consumption - I have no money.!
 
You might be better off getting a Civic or Jazz or a Yaris, they are great on fuel, the Accords are heavy drinkers regardless.
 
exec said:
You might be better off getting a Civic or Jazz or a Yaris, they are great on fuel, the Accords are heavy drinkers regardless.
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Yes correct - but they cost more. No Money.

Accords are cheap, that's why I have one.
 
The 7th gen Civic's are cheaper, can be bought for less thank 1k. Recently bought one for my Uncle, 1.6 version, and its very fuel efficient. You might spend like a £100 more to buy one but then you save more on fuel and other running costs like tax in the long run compared to the Accord. The only negative is they aren't as nice as the Accord which is a class above, but they are still fine cars, the Civic really grew on me after disliking it at the start.
 
flyerphil said:
Yes I suppose it does all add up.

I sold the other car because I was broke financially. I have been unemployed a long time and cannot get a job, apart from tutoring students during the winter months.

I may have to sell the one I have now if I don't get some income soon. This is why I am so obsessed with fuel consumption - I have no money.!
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Crikey, I did wonder why you removed the O2 sensor and cleaned it with lemon juice. If I win the lottery I'll send you a PM and several £k by paypal (I jest not).

But without any money to spare, your investigations are going to be limited. Let's look at the engine logically ....the ECU gets the following information
1. manifold pressure (I think that Josh is right)
2. throttle position
3. engine rpm
4. oxygen in the exhaust

One would think that, with a closed-loop system, the fuelling should not go wrong, but AFAIK there is no difference in the oxygen in the exhaust when the engine is running slightly rich, rather than at the "normal" 15:1 ratio (aka stoichiometry).

So if the info from any of those is slightly out, then it could be running slightly rich.

The other thing that can affect correct running is any of the outputs, which are
A. ignition timing
B. injector timing
C. fuel pressure

If any of those are out, then again, it could run rich .....too much fuel pressure (unlikely), injector(s) opening too long (possible), poor or retarded ignition.

One final thought, if these engines have knock sensors (7th gen does), then maybe the knock sensor is causing the ECU to retard the ignition too much.

As I say, carbon build-up is also a big factor affecting mpg in a petrol engine, but best to try the EGR next, you never know.
 
Thanks Brian. I did look at the plugs, but they appear a good color and not overly black. But that is a crude check.

I guess its just a case of trying everything. I do keep the tyres pumped up hard and drive like an old man - I am an old man ! (61) and rarely use the VTEC.

Thanks for the offer of your lottery win, but if you know someone who wants an ageing Systems Engineer with 40 years experience (USA, Italy, Holland, Germany) and plenty of paper qualifications - then let me know!
 
Does yours have an OBD socket? Do you have an OBD scanner?

If so, it would be interesting to know the short term fuel trim (STFT) and the long term fuel trim (LTFT) values, since these influence directly the fuel consumption.

Take a look at the following videos. This guy explains in detail these concepts and how they can be used to diagnose a car:

https://youtu.be/5WnM_NsOtd8
https://youtu.be/cARQ0jZZ4Qc

Unfortunately, mine doesn't have an OBD port, so I can't check the values of mine...
 
Before you start hacking the ECU and messing with tyristors....

you could check for binding brake calipers. Particularly the rear ones seize over time which leads to high fuel consumption.
 
demian said:
Before you start hacking the ECU and messing with tyristors....

you could check for binding brake calipers. Particularly the rear ones seize over time which leads to high fuel consumption.
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Yes that would be an easy check. But they check this on the MOT don't they. It passed fine not too long ago. Still perhaps I will jack up the rear end and check. Thanks for you input
 
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