Excessive fuelling on 2.0 8V coupe
 

As above, my newly acquired 1996 2.0 8v coupe seems to be using excessive fuel.

I ran the tank to empty yesterday then put £5 in, drove to coxy's and back today (very carefully) which is a round trip of 22 miles and the tank is empty again! So the car is doing about 22 miles per gallon if I nurse it which is well below book figures, not only that it seems worse than my old 16V and coxy's 20V!

Weirdly the car does not smell excessively of fuel when its idling as you might expect if there was a leak or was running rich. Also I've checked the air filter in case that was blocked and causing havoc with the MAF sensor but that looks nice and clean.

If anyone has any suggestions on what to check next that would be great as I'm a little unsure where to look next.

Cheers

Tim

Drop the 16v in!

is it possible you are actually losing fuel from some where maybe filter or similar as opposed to running rich

Might do at this rate, problem is its missing a few bits now! Also if I did drop the 16V in would I have to go back to a CAT exhaust for the emmisions test as the 16V was a 1993 and the 8V is a 1996?

Its possible but as I say the car never smells of fuel and I've never noticed any leaks on the ground where its parked. :confused: The fuel pump does have a slight whine but I'm not sure this is of any significance.

if your loosing it when its running/moving you wouldnt notice it so much and the wind would push smells away from you

Hmm, you might have a point but wouldn't it be losing it when stationary too?

Mine used to run at about the same mpg, pretty much exactly the same! And I never smelt any excessive fumes or anything but changed the lambda sensor and started getting around 35 mpg.

The old one was black as anything, no wonder it wasn't working! Might be worth a look.

Also, the cold start valve / fifth injector stick open aparently. You just need to warm the engine up, pop it out and plug the hole then turn the engine back on, it shouldn't release any fuel when warm.

Hope that helps :)

Thanks Skinny man, will take a look at both those suggestions. :tup:

Problem is, the injectors are pricey (around the £100 iirc :eek: ) but easy to fit. The lambda sensor is less so (I paid about £60 I think) but a ballache to fit lol.

The cost is offset in what you save on fuel though, at least :tup:

Good luck, hope you get it sorted. :rock:

Cheers fella, will report back if not.

think i've got a 5th injector kicking around in my parts stash somewhere fella.

Hmm, cool. Rob took a look at it a few weeks ago and he reckoned the 5th injector setup was working fine but when put on the analyzer it was off the scale rich so pointing at faulty lambda maybe?

cool, tis most likely to be lamda related or even the coolant temp sender failing and telling the engine to run rich (had that one on my 8v mk3 gti).

Or the thermostat. Is temp guage working ok?

Could maybe try unplugging the connector for the fifth injector/ cold start valve, therefore rending it inoperable and see if that improves things. If nothing changes you can just plug it back on.

EDIT - Just read elsewhere someones already suggested a similar thing.

Any updates on this.

Just do a full service, plugs, air filter, rotor arm, and o2 sensor. Maybe ecu side temp sender.? about £4..
Cures allsorts of problems.

You cant even start to guess problems without doing the basics.

Hmm, OK well I've now swapped the lambda sensor over from my old car and things seem a little better, still not sure if its fully sorted but difficult to tell as I'm doing a lot of short journeys at the mo but looking more like 30mpg now rather than the low 20s it was. Lambda was my initial guess as the outer cable on the old one looked a little chewed up like it had been snagged up in something at some point. Inner cable looked fine but you never know if its broken down the copper cable inside I guess. Will get it on the analyzer again when I get chance and check the mixture levels.

Cheers for all the suggestions people. :tup:

Spot on Sir !

having had the B4 Sport for a couple of months now I have come to the following conclusion

Commuting - 16V beats the pants off the 8V

On a long run the 8V wins but mine does have an extra high 5th gear

Don't tempt me :) I keep having to talk myself out of this as it is. Time is the main problem, oh and getting the engine crane back off Krez!

that'll be my crane which I've seen once in 3 1/2 years....

and that was when Garrick used it to remove the engine out of my 80 sport!!!:lol::lol:

Can't believe it made it back to the yard for a day and then you let it go again! :shake::lol:

I still feel quite guilty about the crane, it was me that first liberated it from coxy towers to do the type 4 conversion in the fasty! i picked it up in the back of a sierra estate which tells you how long ago it was!

I had to let Garrick use it to put his engine back in the golf else he might not have bought it off me!!!

Damn, a sierra estate! That was probably the last time anyone saw one on the road!!

Proper old school daily :)

I was just trying to think how many years ago rapid owned a fasty? at least 3 me thinks?

and the rest, I'd say more like 5-6 years ago.

Still got the mark at the bottom of our drive where he bottomed out on the kerb stone (the lowered part of the kerb!) :lol::lol::lol: