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Inspired by the fuel injection posts of late, thought thats for me. purchased all the bits, fitted and got the engine going (runs great) Had the engine programmed on a rolling road (yes VW specialist). However really bad MPG, in the region of 20mpg.

What could be wrong??

the engine is a 1641 fitted to a camper, produced 59BHP at the rear wheers, I don't thrash it. the mpg figures were obtained on long runs at about 55mph,@ 3200rpm, but it would go a lot faster. I have the coolant and air sensors in the correct place and the fuel returns to the tank

Whilst I appreciate that its very difficult to identify problems without seeing it. I was hopeing for any gross errors I may have made.

Thanks in advance

steve
 

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It might not be just the FI's fault. Poor MPG can be a number of things: Huuge deck height, worn engine, naff heads/valves, wrong cam, wrong compression, wrong gearbox, wrong tyres, etc.

There was a chap on here who chipped into the massive megasquirt thread we had a while ago who was running megasquirt on a 1776cc camper and getting close to/over 30mpg. does this system do your timing as well? Has it got a wideband sensor?

Have they tuned the engine for performance or MPG? An engine can be set up in different ways. If you're after MPG, better to run it as lean as you dare on cruise and not too excessive on full throttle. You need wideband, oil temp and cylinder head temp to make sure you're not cooking things though.
 

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What ignition system are you running? If you're running a 009 it might be worth investing in a better system.

Also here's a thread I put up ages ago about using a standard oxygen sensor from a scrap car to read the fueling. I personally wouldn't worry too much about a wideband sensor as it's pretty obvious when the mixture is too rich or too lean to be read.
Here:
http://www.volkszone.co.uk/VZi/showthread.php?t=180708
 

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72_Square said:
There was a chap on here who chipped into the massive megasquirt thread we had a while ago who was running megasquirt on a 1776cc camper and getting close to/over 30mpg. does this system do your timing as well? Has it got a wideband sensor?
That would be me... :)
On the way back from Vanfest sitting at 60+ I used 35 litres (7.6 gallons) for a distance of 240 miles from Malvern to Southwaite services. I am getting over the obsession of mpg now!
Your problem might be engine size because at the speed we came back I wasn't stressing the engine and sitting at a quarter throttle. when it came to hills there was plenty left to keep the speed up.
As previously mentioned it could also be engine condition or state of tune. If you're confident the FI is set up properly, this is where I'd start looking.
 

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Personally i'd concider 20mpg on a mixed cycle pretty good for an old engine in something with the aerodynamics of a breezeblock.

Heads and general wear on the engine will affect MPG as much as the fueling system. and obviously a 1664 will run at consitently higher revs than a 1776...
 

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Originally Posted by Angelvenomous:

Also here's a thread I put up ages ago about using a standard oxygen sensor from a scrap car to read the fueling. I personally wouldn't worry too much about a wideband sensor as it's pretty obvious when the mixture is too rich or too lean to be read.
Narrow band will give you guidance, but if you're trying to fine tune, you can't beat a wideband. I've got an Innovate LM1 on mine. Expensive, yes, but worth it for piece of mind. You can do it cheaper with a diy version, or the LC1 for about £100.
 

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2-bob Monkey Mafia said:
Personally i'd concider 20mpg on a mixed cycle pretty good for an old engine in something with the aerodynamics of a breezeblock.

Heads and general wear on the engine will affect MPG as much as the fueling system. and obviously a 1664 will run at consitently higher revs than a 1776...
On what bases have you based your findings on then?

Is a 1664 the new 1641 :incheek:
 

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72_Square said:
Originally Posted by Angelvenomous:

Narrow band will give you guidance, but if you're trying to fine tune, you can't beat a wideband. I've got an Innovate LM1 on mine. Expensive, yes, but worth it for piece of mind. You can do it cheaper with a diy version, or the LC1 for about £100.
As he says :)

I have the same set up and can highley recommend the innovate lm1 having personaly used this system to tune both the polo and fugative
 

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I have a stock 1584 bay with 36 DRLA's set up on a local rolling road. It does 28 to 30 on a run at 55mph. And 24 - 25 mph whilst towing a bug to the pod. So 20mpg with fi sounds like somethings not quite right.

Cheers
Mick
 

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72_Square said:
Originally Posted by Angelvenomous:

Narrow band will give you guidance, but if you're trying to fine tune, you can't beat a wideband. I've got an Innovate LM1 on mine. Expensive, yes, but worth it for piece of mind. You can do it cheaper with a diy version, or the LC1 for about £100.
Correct, it will give you guidance. A narrow band will only tell you that you are running around stoich which is what a catalytic converter requires. For better economy you can actually run a fair bit leaner, but the narrow band won't tell you where you are then
 

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PRO33 said:
On what bases have you based your findings on then?

Is a 1664 the new 1641 :incheek:
All your bases......

i find pedantry works far better when you don't employ typo's of your own in the post. :rolleyes:
 

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2-bob Monkey Mafia said:
All your bases......

i find pedantry works far better when you don't employ typo's of your own in the post. :rolleyes:
Ok I have altered my spelling mistake so here is the Question for you

On what basis have you based your findings on then?

Is a 1664 the new 1641 :incheek:
 

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PRO33 said:
Ok I have altered my spelling mistake so here is the Question for you

On what basis have you based your findings on then?

Is a 1664 the new 1641 :incheek:
on what did i base my findings?

I don't believe that i offered any 'findings', merely an opinion based on the fact that spec for spec, a 1641cc motor would have to rev harder to produce the same specific output as a 1776cc motor.

And that head design has a significant effect on fuel economy, based on the published papers on the Jaguar 'HE' modifications of their V12 engine, and the 200 plus sets of heads i have cut commercially for Harley Davidson, Honda and Rotax powered Flat Track racers. Sorry i cannot offer an anecdote based on my own camper van.
 

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caryally said:
Inspired by the fuel injection posts of late, thought thats for me. purchased all the bits, fitted and got the engine going (runs great) Had the engine programmed on a rolling road (yes VW specialist). However really bad MPG, in the region of 20mpg.

What could be wrong??

the engine is a 1641 fitted to a camper, produced 59BHP at the rear wheers, I don't thrash it. the mpg figures were obtained on long runs at about 55mph,@ 3200rpm, but it would go a lot faster. I have the coolant and air sensors in the correct place and the fuel returns to the tank

Whilst I appreciate that its very difficult to identify problems without seeing it. I was hopeing for any gross errors I may have made.

Thanks in advance

steve
I got 34mpg from my 2387cc turbo bus on the way down to bugjam this year and I did give it plenty on a few occasions but mainly just cruising. I'd say that you have sticking brakes or the set up is crap.
 

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2-bob Monkey Mafia said:
on what did i base my findings?

I don't believe that i offered any 'findings', merely an opinion based on the fact that spec for spec, a 1641cc motor would have to rev harder to produce the same specific output as a 1776cc motor.

And that head design has a significant effect on fuel economy, based on the published papers on the Jaguar 'HE' modifications of their V12 engine, and the 200 plus sets of heads i have cut commercially for Harley Davidson, Honda and Rotax powered Flat Track racers. Sorry i cannot offer an anecdote based on my own camper van.
I was thinking more on the lines of why you thought the engine in question may be old and worn this being a reason for piss poor fuel consumption do you know this person or his engine so have a little more information to go on than the rest of us ?

Jaguars were my dailys for around 8 years and had both pre He and He V12 jags so am aware of HE modifcations made in 1981 but am at a loss as to how this effects vw flat floor fuel consumption

You may have a rudimentary knowledge of motor bike heads but this threads not about this is it.

Again I ask what basis or experiance have you on vw flat 4 fuel injection engines to state that 20 to the gallon is exceptable ?
 

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PRO33 said:
I was thinking more on the lines of why you thought the engine in question may be old and worn this being a reason for piss poor fuel consumption do you know this person or his engine so have a little more information to go on than the rest of us ?

Jaguars were my dailys for around 8 years and had both pre He and He V12 jags so am aware of HE modifcations made in 1981 but am at a loss as to how this effects vw flat floor fuel consumption

You may have a rudimentary knowledge of motor bike heads but this threads not about this is it.

Again I ask what basis or experiance have you on vw flat 4 fuel injection engines to state that 20 to the gallon is exceptable ?
boring.

I didn't say that wear WAS the reason, but that it may be a factor.

so VW's run on different engineering principles to the rest of the automotive world then ??

So, given your close to encyclopedic knowlege gained on the single vehicle you offer as an example, what's your suggestion as to the problem??
 

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2-bob Monkey Mafia said:
boring.

I didn't say that wear WAS the reason, but that it may be a factor.

so VW's run on different engineering principles to the rest of the automotive world then ??

So, given your close to encyclopedic knowlege gained on the single vehicle you offer as an example, what's your suggestion as to the problem??
Could I ask what real experience you have?

I noticed you posted some advice on a nitrous thread so I'm figuring that you own and run a fuel injected nitrous motor
 

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2-bob Monkey Mafia said:
boring.

I didn't say that wear WAS the reason, but that it may be a factor.

so VW's run on different engineering principles to the rest of the automotive world then ??

So, given your close to encyclopedic knowlege gained on the single vehicle you offer as an example, what's your suggestion as to the problem??
I am very disapointed that you find my enquiries boring

This 1 vehicle happens to run programable fuel injection and a not to dissimilar cc so I feel I am able to suggest a couple of pointers

If you read through my past postings on this thread I have asked earlier in the day what the fuel injection set up was and I no doubt will hear from caryally in due course

Then when armed with a little more information I may be able to help [or I may not if I have come accross these componants that make up the guys system]

But the one thing I would not dream of doing is stating 20 per gallon is exceptable when I have had not experiance of this installation
 

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72_Square said:
Narrow band will give you guidance, but if you're trying to fine tune, you can't beat a wideband. I've got an Innovate LM1 on mine. Expensive, yes, but worth it for piece of mind. You can do it cheaper with a diy version, or the LC1 for about £100.
Well I'm a tight git and proberbly won't pay that much! ;)
I've always had good results when using an O2 sensor from a scrap car. If the reading is 0.3 volts that's a pretty good indication that you're about to burn a big hole in your pistons.

That said, I still rely more on setting up fuel mixtures by "sound and smell". I drove my 1600cc Bay with twin 36 Weber IDFs to Germany and back a couple of weeks ago and averaged about 35 mpg at a constant 60 mph.
 

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2-bob Monkey Mafia said:
And that head design has a significant effect on fuel economy, based on the published papers on the Jaguar 'HE' modifications of their V12 engine, and the 200 plus sets of heads i have cut commercially for Harley Davidson, Honda and Rotax powered Flat Track racers.
Nice!
 
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