poor economy on 1.8 16V

[leigha 0]

our new 1990 1.8 16v corrado is doing on average 16mpg around town and driven sensibly according to the display! if driven nicely out of town (steady 50mph) it will only struggle to get to 22mpg!!!

 

at present i have no way of backing up the electronicly displayed mpg figures but it seems thirsty. (the odometer has packed up!!!)

 

the mods on the engine are a large bore downpipe and centre section, and a ported throttle body, otherwise original. milage is around 112k so not excessive.

 

what are the best places to start fault finding? and what ecomomy should i get?

[steveo29 0]

id suggest you try and work it out propery....maybe fix the odo, as you cannot trust the mfa display

 

causes for bad consumption.....flat tyres,binding brakes,engine needs a service and or set up

[bcstudent 0]

I get about 30-32mpg combined with about 50/50 town and B-road driving. My MFA isn't that far out usually but I wouldn't believe it if it was telling me I was getting 22mpg out of town! Clearly, there's no way to prove it either way without a working odometer.

[leigha 0]

i hoped the MFA (so that's what it's called) was untrustworthy!

 

in that case, the odometer it the next port of call.

 

my bro has a spare set of clocks from a J plate Polo coupe GT, would these be a possible parts donor for an odometer?

 

(can you tell i'm new to VW's!!!!)

[gsbellew 0]

Sounds just like mine (well one of mine) have yet to figure it out myself yet though :oops:

 

I get 8 - 16 on short trips, 24 seems to be my maximum now, all ties in with the actual calculated figures too :cry:

[leigha 0]

nasty!!!

[bcstudent 0]

I agree. I can barely tolerate 32mpg considering the performance available; I think 24mpg would prompt an advert in the Autotrader!

[dr_mat 0]

Averaged 34 mpg on the way up to Stealth the other week in the VR ...

[davidwort 0]

...my bro has a spare set of clocks from a J plate Polo coupe GT, would these be a possible parts donor for an odometer?

...

 

 

nope, a passat one would be the nearest although the rev counter units would need to be swapped unless you find a passat GT

[Toad 0]

I average 29.1MPG (according to the MFA, I know I need to calculate it properly but i can never remember to zero the mileometer) I had a play last night and got it up to 37MPG, but that was when the car was warm, and took loooooaaaads of concentration and driving like a granny. It did average about 38MPG when cruising at 60mph in 5th.

[Phil K 0]

That spretty good mate... I know mines a 2l but I gen get low 30's and managed a good 34mpg going to and frm the G Werks day on Sunday (was driving like a loon too :mrgreen: )

[rosswalker 0]

I average around 30 in my VR6, but have managed 37 when I was following my mum :)

 

- Ross

[chubbybrown 0]

usual figures are 34-36 on a run in top around 60

round town 30

booting it once warm about 27

[leigha 0]

...my bro has a spare set of clocks from a J plate Polo coupe GT, would these be a possible parts donor for an odometer?

...

 

 

nope, a passat one would be the nearest although the rev counter units would need to be swapped unless you find a passat GT

 

curses! do you know what years the passat had the right bits? did any other VW's have one that works the same?

[leigha 0]

That spretty good mate... I know mines a 2l but I gen get low 30's and managed a good 34mpg going to and frm the G Werks day on Sunday (was driving like a loon too :mrgreen: )

 

my current fuel economy and a few technical issues kept me away from there... bah! (pas wasn't working, tracking waaaaaay out, etc etc) was it good?

[leigha 0]

hehe! the tyres were bad when we bought it but are now screwed!!!

 

the plan for this weekend is to fit one new track rod end (the other is new), both new bottom swivels and both rear wheel bearings (loose and noisy!) then get the tracking done finally once. then some new tyres that aren't cone shaped! that should help things along a bit!

 

should handle a bit better once it's done too!

 

Corrado16ved, pm on it's way!

 

edit... for some odd reason the forum is putting my post before the next two...

[.A.N.T. 0]

my current fuel economy and a few technical issues kept me away from there... bah! (pas wasn't working, tracking waaaaaay out, etc etc) was it good?

 

You're starting to answer your own question there... I'd get the tracking looked at asap as not only are you lowering the mpg, you're wearing the tyres out too...

[leigha 0]

update:

 

i have the tracking and tyres all sorted now but the economy is still very poor. the milometer is still not working (bits on the way!) but jusding on £ per week compares to previous cars, it's at best doing low 20's to the gallon. this is similar to the 192 bhp bmw 525i sport it replaced and that went due to economy!

 

something someone mentioned to me... does the 16V engine have a lambda sensor in the exhaust?

[ben16v 0]

does the 16V engine have a lambda sensor in the exhaust?

 

not on the 1.8l

[leigha 0]

that's one less thing to worry about then! that also explains the spark plug in the lambda probe hole in the exhuast!

[Supercharged 2]

Nice! - buy a really long HT lead!

[leigha 0]

it's a part made flamer kit! if i extend one HT lead to the plug in the exhaust, i reckon it'll ignite the unburnt fuel a treat!!!!

 

kerbooooom! ;)

[Crasher 3]

Check the vacuum feed to the dash from the pipe coming of the servo feed pipe at a "T" piece.

[leigha 0]

will do, cheers.

 

what does it do?

[bcstudent 0]

It's the vacuum connection to the part of the clocks that works out the economy. The more you open the throttle, the more vacuum is created, and it just uses a look-up table to determine the fuel usage at certain vacuum levels. It's pretty basic and not to be believed with less than a pinch of salt.

 

However, that said...if the pipe is leaking vacuum then it'll over-read rather than under-read, i.e. if the pipe falls off you'll see 99.9 mpg because it's seeing no fuel usage over any distance.