Hi,

I 've been following this forum for a while and it is very useful

Recently, the 07 reg vrs fabia developed a rough idle. I read extensively what could be the cause

The skoda dealer at Doncaster wanted to do diagnostic for 70quid when there was no engine check light and local indie who is very good when a problem can be specified sounded like a money pit and non committal.

I decided to change the egr, 110 quid later with new o rings and gasket the rough idle was gone

I also cleaned the intake manifold as best I could using a spoon and removing the black gunk to me

Also the throttle body was cleaned.

I also cleaned the inter cooler and pipes due to the oil drūip which dealer said was normal for vrs.

The car was test driven and I noticed it warms up to coolant temp quicker and was less hesitant at low revs. The fuel economy seems to have dropped though unless it is taken on longer distance drive.

Is this normal? Because the new egr works should I expect the egr to be closed and unburnt fuel on warm up to be lost to exhaust rather than cycling though intercooler and extra pipework?

Could the Maf sensor be at fault? Which has lead to a rich fuel mixture?

I disconnected and drove round with and witout maf connected but did not notice any difference.

Could maf fault lead to egr premature gunk build up?

Ive ordered some electrical contact spray cleaner.

What is unclear is that some people state contradictory info about the Maf, such as disconnecting Maf will indicate it is at fault if there is difference, others state opposite. I'm confused.

Any ideas? Car is well looked after with 66 k on clock. Thanks Matt

No point in replacing the maf without checking vcds data. If you get the free vcds lite and a cheapo cable you can connect your laptop to compare the estimated air consumption and the readings from the maf. They should be roughly the same. Total waste of money unless you do that first or have another indication it is bust

[sNIP]

Is this normal? Because the new egr works should I expect the egr to be closed and unburnt fuel on warm up to be lost to exhaust rather than cycling though intercooler and extra pipework?

 

{SNIP]

 

 

EGR is nothing to do with unburnt fuel getting cycled anywhere, and nothing is cycled through the intercooler, the exhaust gases are piped straight from exhaust manifold to inlet manifold, via EGR valve.

 

A slight drop in economy might result from a working EGR valve replacing a stuck shut non-working one, due to the lower peak combustion temperatures that the EGR use causes (thus reducing NOx emissions, the whole point of the valve).

Thanks for info. Matt

Diagnostic scan revealed no faults, but the maf data did not match on idle., too high on air flow and out of serenaded range. 450 ppm rather than upper limit of 270ppm. Replaced maf . Will report back on any change to mpg

Rough idle previously due to blocked egr has loosened the engine plastic cover causing it to vibrate. Checked tightness of all engine mount bolts also. None were loose.

Feedback - on the morning journey (from cold start) of 20miles to work the  Fabia 1 vrs BLT 1.9 did 54mpg, normally would do upper 50s (58). The car is smooth between gear changes, but no big changes to the mpg.

 

I did notice on the diagnostic that the engine temperature was reading fine 90C so that sensor has not gone.

 

Any other ideas?

 

I've had 72mpg out of this car on a long journey and the mid 60s is normal mpg for many journeys involving 5-6 gear. Could the ECU computer be calculating mpg differently with a functioning EGR?

 

Next step is injector cleaner BG.

 

Fuel filter was replaced 3 k (Mann) - Worth changing? Although, there is plenty of power on tap.

Edited 26 April, 201610 yr by bmbmdmb

were you getting the high mpg figures you quoted in the middle of summer or a different time of year to now? change in temperatures can have an effect on mpg, I usually see the mpg on the readout drop in the colder months. To be honest I don't pay much attention to the mog readout anyway and just workout my consumption from tank to tank, that's the most accurate way and something I would suggest focusing on as opposed to the computer

Just had 62 mpg on journey from Sheffield to hull driving on cruise control at 70mph. Minimal traffic. Does that sound about right?

I've had high 60s mpg on motorway using trip computer

Think I've solved it. Looks like binding brake caliper.

The rear right alloy was warm to the touch. The disc was very hot, water boiled off its surface. All other discs were cold to the touch. This is despite air temp being 1cCelsius and hail and rain I had in Yorkshire.

I've had to replace front calipers due to split rubber. Local garage did rear discs around Xmas and pads

The rubber is not split after stripping pads out and cleaning. On reassembly the brakes were tested again and the brakes are releasing but not completely. I will tomorrow check other side to compare.

Could be wheel bearings? No play though.Although the heat was most definitely from the brake disc

The heat has scorched the metal of the edge of the brake disc.

Would anyone recommend genuine green or pagid calipers unpainted. Car parts site price range from 115 to 66 when old one traded in.

Must be sticky piston. Will do work myself this weekend.

Hammerite Buckinghamshire green garage door paint looks good. Slightly darker than new spec

Thanks for replies Matt