MPG going down and down

B

bean

Guest
When I first got the R it was running standard boost and did around 280miles to a tank.

I upped the boost to maximum on the standard gauge, 700mm/hg and still got around the same miles too a tank.

Recently I seem to only get 220 miles too a tank and the boost won't go past 500mm/hg on the gauge. WTF is going on? :x

It's had a recent service including oil & filter change, dizzy cap and rotor arm, filter element.

Any help appreciated. :oops:
 
Fast Guy

Fast Guy

Moderators
Staff member
Any signs of it running rich? Black smoke? Could be the maf sensor, o2 sensor or just the age of the car :?:
 
J

J-GTi-R

Guest
Does it seem to pull a bit poorly from standstill (a bit fluffy, for want of a better word), and not rev cleanly when you're giving it some?

When mine goes into safe mode, it drops boost, but it also uses HUGE amounts of fuel. If you car's black, wipe your hand over the back of the car near the exhaust and see if there's any soot (mine's red so I can see the sooty deposits), as that's a sure sign that it's running way over-rich.
 
A

Anonymous

Guest
280miles to a tank!!! Even driving like a granny mine is lucky to get over 200.

In the odd times mine has restricted the timing and boost, it uses loads of extra fuel.

I have also been told that crap mpg can be attributed to a blocked injector which causes it to weep.

Dan
 
B

bean

Guest
I've just changed the rotor arm and distributor cap, they were badly in need of replacement.

Seems to run much better now. :)
 
B

bean

Guest
Neostar said:
280miles to a tank!!! Even driving like a granny mine is lucky to get over 200.

In the odd times mine has restricted the timing and boost, it uses loads of extra fuel.

I have also been told that crap mpg can be attributed to a blocked injector which causes it to weep.

Dan
Click to expand...
Interesting, can you clean injectors by running some sort of Redex stuff through them or do you have to remove them from the fuel rail and clean with a scrubbing brush? :?
 
A

Anonymous

Guest
Like FastGuy said its usually best to get them done properly, but a few doses of redex would probably free it up enough to tell you if it is the injectors or not.

Still haven't figured out why a blocked injecctor would actually give you worse mpg, but that was what I was told :?:
 
J

jasegould

Guest
My fuel economy has improved loads by having the timing set properly... :?:
 
Fast Guy

Fast Guy

Moderators
Staff member
A patrially blocked injector will still flow fuel, but in a cr*p spray pattern. This won't atomise properly in the cylinder and therfore not burn properly, so you're down on power in that cylinder.

So the chances are you give it more throttle (without realising) to make the same power as before and therfore use more fuel.
 
GTIR-LOZ

GTIR-LOZ

New Member
yeah i have found that since putting on my front mount my fuel consumption seems to have doubled in effect :cry: i can only really put this down to having to use a bit more throttle on lighter acceleration, to compensate with the longer pipe run and hence more lag
 
Fast Guy

Fast Guy

Moderators
Staff member
I'd have thought that would more likely be to do with getting more (cooler) air into the engine, needing more fuel to burn with it. Unfortunatelt I didn't realy notice my mpg on the way to the pod on sunday. I'll have to keep an eye on it the next long trip I make.
 
A

Anonymous

Guest
My fuel consumption recently became very bad all of a sudden, 100 miles to a full tank :shock:

It turned out that my Lambda sensor is knackered causing overfuelling!
 
B

bean

Guest
Come to think of it, boost has been lower since I remove the IC to replace the rotor arm and distributor cap.

I wonder if I've disturbed something?

I'll check my injectors while I'm at it, are they hard to remove? :?:
 
GTIR-LOZ

GTIR-LOZ

New Member
the only thing you could of done really is either left the boost pipes disconnected form the intercooler piping (the one that runs under the cooler, or maybe you have put the breather pipe back onto the pipe instead of the boost pipe from the wastegate , this is quite easy to do :oops:
 
B

bean

Guest
Checked last night, not boost or breather hoses disconnected or connected the wrong way round.

BUT, I noticed the injector nearest the drivers side (dunno if that's 1 or 4) does appear to be weeping a bit. :(

How easy is it to remove the injectors and check them out?
 
You must log in or register to reply here.
Top