Picked up my fabia a few days ago and its gorgeous

Thing is (yes its still all under warranty) that its only fetching about 45mpg whilst driving quite tame. Just to list the things that would affect it that much as from having other vehicles with similar engines fetching about 55-60mpg on the same trip driven the same I felt I should have gotten more.

Its just been serviced and has a FSH. 80k miles

Drives smoothly and doesn't hesitate.

I was gonna connect it up to VCDS later (when I find the obd port lol) and see if theres any faults. It isn't overboosting as far as I can see as its not hitting limp mode. No engine management lights. MAF would usually mean quite a lot of hesitation wouldn't it? Tyre pressures seem ok. Doesn't feel remapped. Sticky brakes would feel quite apparent I'd guess.

Could be that the cambelt change 5k ago previous owner could have the timing a bit out of spec?

 I was gonna connect it up to VCDS later (when I find the obd port lol)

 

Right of the steering wheel, pull open the compartment, then pull a bit harder and it will reveal the magical tool.

 

Pretty sure you'll get a couple of things returned which are "normal" to do with airbags and electrial current or something similar.

I removed this from my car after 96k and I'm convinced it plays a big part in my poor fuel economy .....

At this time of year, there is also additive in the diesel to stop fuel coagulating, which does affect mpg a bit.  Also at this time of year the cars take longer to get to operating temperature, which can have slight downward effect on economy (but cold air gives more power )

I'd remove the EGR valve to see if it's clogged up. Can drastically affect MPG if it's clogged up!

 

I made a guide on how to remove it to clean it!

 

Here

Don't forget an Italian tune up! You have no idea how the previous owner drove it. Blast the cobwebs out  :p

 

Check the timing as well, can have quite an effect on these engines. You can pick up a cheap OBD lead off ebay and VCDS lite and do it yourself. Module 4 field 4 if I remember correctly? Wants to be as close to zero as possible.

Driver tune up, perhaps. :think: if it's a deisel ,then change up a bit eaerlier.

I find best way to increase mpg... glue a big block of wood under that pedal on the right in the drivers footwell. Bigger theblock the better the mpg.

but do not use the midle pedal!!!

I drove it going for mileage, let off the gas, keep in gear, coast in gear and do not brake. hmmm

 

timing was 0/-0.6 flickering which seems fine. no engine related faults logged. I reset all faults so I have a clean slate to test (after saving the log of course).

 

I have also done a WOT run logging the MAF and the turbo boost pressure 

Log is here http://pastebin.com/V33rGU0q

 

I can't see anything there causing it. It would be a good time to check the EGR and for boost leaks I suppose.

Are you a fat ******? 

 

I jest... but loosing weight will help your 0-60 but 0.004 sec :p

Edited 11 February, 201412 yr by Gobsheene

Are you a fat ******? 

 

I jest... but loosing weight will help your 0-60 but 0.004 sec :p

 

Nah!!! Only 11.5 stone...on a good day anyway :P

 

Do the requested boost and MAF levels look mapped? http://pastebin.com/V33rGU0q

 

Wonder if it has a pants map, I'll also keep an eye out for one of those terrible tuning boxes - is it the same as the Golf ones? Connected to the fuel temp sensor front of the engine bay?

 

I'll check tyre pressures today and the EGR later (if I feel like freezing my ass off outside!) 

Snow.

That's the answer!

Snow

It's snowing here in GOC (Gods Own Country) meaning the air is colder and ergo denser. Plus snow stops SWMBO bombing around so it keeps the mpg up in the high 50's

As a giggle, she's got a blind lady in the passenger seat today, I told her her to inform said lady it was snowing and that she was doing 80mph, jus for the fun of it...

Tested driving with MAF disconnected. Quite sluggish!

 

Got the go ahead to remap and also keep my warranty which is cool

 

Suppose I better go have a gander at the EGR and if appropriate clean or blank off!

Checked out the EGR this morning.

 

 

Seems clean enough to me   was hoping this could be a quick fix! Wonder where to check next...boost leaks? 

1. Clean MAF with contact cleaner

2. Carry out full service - replacing fuel filter

3. Carry out boost leak check ( splits in pipework, damaged hose couplers)

Checked out the EGR this morning.

 

 

Seems clean enough to me   was hoping this could be a quick fix! Wonder where to check next...boost leaks? 

 

I'm not sure if you're joking? haha

 

The actuator rod is covered in crap! The outer wall is fine though.

 

If your egr is opening and refusing to close due to all that build up around the valve then it'll be chucking exhaust fumes in constantly giving you bad MPG.

I was looking at the outer walls to be fair. Didn't occur to me that the gas valve could be stuck open due to crud. I'll whip it off and get some carb cleaner on the case tonight. Worth blanking off eventually?

 

As for the MAF, from my Golf days could electrical contact spray cause damage to the sensor? 

 

Either way I'll try the EGR first

The weather, with some of the wind lately I've been dropping 10-15MPG at times.

Cleaned EGR out last night - oil and crud everywhere. 

 

Got a remap today too. Epic! No boost leaks and everything seemed ok to them. Got 170/300lbs now, all smoothly delivered. Got 50mpg on the trip home with plenty of "testing" too.

 

Blanking off the EGR soon too. Hopefully it will only get better - plenty of thrashing required I think!

 

Fuel additives are just snake oil right? What about terraclean? Swear it did more harm than good on my golf

Just an update. 

 

I keep giving it the ol' beans up to redline, shall i hold it there or change gear and repeat, then maybe slow down and repeat again (as opposed to holding it there?) I always wait till i'm at temperature mind you.

 

Also put a bottle of forte advanced in and will be doing a spirited drive to the airport on friday. 

 

Had a custom remap and they checked everything over before giving it the beans on the dyno (170/300lbs btw) so that would have cleaned it out too

 

No boost leaks (smoke tested) and no faults logged. I'll clean the maf anyway just in case although i'm sure they would have struggled to get 170 out of it with dodgy maf. 

 

Just seems a bit harder to keep at a speed without using the pedal that tiny extra bit more, but then again it doesn't seem to slow down too much when rolling in neutral (only for purpose of testing for sitcky brakes!) 

 

So planned is to blank off the EGR properly (both ends and remove EGR pipe) and to give the maf a spray with electrical contact cleaner. 

Have you checked the oil level in this? 

 

I read somewhere that someone got a 10mpg reduction just because it was filled with too much oil. Might be worth a look.

 

Might have been in this thread actually haha haven't re-read.

Havent checked that as I'd have thought they would do it correctly! 

 

Got 450 miles mainly motorway from home to london and back again before the light came on, and thats using the expansion tank - car computer claimed roughly 48mpg.

 

I got my blanking plates today so i'll get the egr properly blanked and check the oil (!!!). Found the car does lose momentum pretty quickly when i lay off the throttle but not that apparent in neutral so possibly not dragging brakes

Mine does about 45mpg as well and i drive quite casually.

Sounds like you have a problem too man.

 

Filled up with shell vpower this morn and drove 50-60mph home (40 mins trip) and got 55mpg which is my record. Think the problem is definitely trying to hold a speed without throttling too much, seems to lose speed whenever I feather the throttle for the big mpg and also seems to drop mpg quickly under any acceleration. 

 

Either way, EGR blanking tonight along with a check on the oil levels. Could it be possible the cat is blocked meaning the engine needs that extra bit of throttle to keep it up to speed?