1.8T Common Troubleshooting Guide

This should be made into a sticky, could help with some of the repeat posts we often get.

Nice bit of info on spark plugs...

>Pricing
Prices can range from less than £10.00 a set(4 plugs) to over £50.00/set. It has been satisfactorily argued that the inexpensive copper core plugs work as well as the expensive Iridiums, with the understanding that the copper core plugs must be changed more often. Copper core plugs replacement intervals seem to range between every oil change to every fourth oil change. I've seen reports of Iridiums lasting up to forty-five thousand miles with just an occasional visual inspection and cleaning.

It should be noted that there has been speculation that frequent coil pack removal may have something to do with the problems they have. Theory is that since a defective coil pack is physically broken into two peices, and that rough removal techniques could help this along. I have seen no documented, concrete evidence of this, nevertheless, be gentle with your coil packs when removing them.

>Stock spark plugs NGK PFR6Q stock gap .032"

--Common replacements

Denso Iridium IK20
Denso Iridium IK22 (one heat range colder)
Bosch F7LTCR
NGK PFR6Q - Standard heat range, double platinum.
NGK PFR7Q - As above but one grade colder.
NGK BKR6E - standard copper core.
BKR6EIX - As above but Iridium centre electrode
NGK BKR7E (Race plug, one range colder, copper core)
BKR7EIX - As above but and Iridium centre electrode

*avoid BKR7E-11 as the factory gap is too large, .042*

For every additional 50HP over stock, a general rule is:
--1 heat range colder
--gap shrinks by .004
So, a chipped 1.8T would make good use ofa plug one range colder gapped to .028

You dont have to gap the plugs unless they are larger than factory gap. Pre-gapping them to the above figures wont do any harm.

Reference: From NGK's FAQ: Spark Plug Gap

"Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005"."

Torque Settings for your plugs

(referenced from the Autolite website)

Thread Diameter......................Aluminum Heads
.................................Pound Feet........Newton Meters
14mm Crush Gasket...15 - 22 lb. ft.........20 - 30 nm


From Bentley Manual :

GAP
0.80 mm max.(0.031in)
Tightening torque 30Nm (22 ft-lb)
Tightening torque for Coil Packs 7ft lbs


How to read your plugs
As you change your plugs, it's a good idea to look over your old plugs to get an idea of how your engine is running and to help asses what your next plugs should be. Mostly your making sure your in the right temperature range, and that everything is consistant in all four cylinders.

-light brown/tan/gray in color they are the right heat range and A/F ratio

-white and you want a colder plug, likely running too lean i.e.: too much air, not enough fuel. (too much boost...)

-black (Majority of faulty plugs fall into this category)
---black and dry, you want a hotter plug
Dry fouling refers to the accumulation of carbon on the firing end of the plug which decreases the insulation and finally leads to miss-fire.

---black and Wet, you want a hotter plug
Wet fouling refers to the black and shiny state of the firing end covered with carbon and fuel which decreases the insulation causing the engine to mis-fire

-Often simply need to simply drive harder, add a freeway run into your short commute or something (quit being a spode and DRIVE the darn thing)
-The fuel setting (A/F ratio) is rich (chipped often run slightly rich)
-dirty air cleaner elements.
-Idling for a long time.
-The heat range of the plug is too cold (using a MBC and no chip(stock))


-reddish could indicate fuel system degredation troubles,iron content, rust?


Where to buy?

I personally use http://www.sparkplugs.co.uk/


Further reading....

http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=US
http://www.spark-plugs.co.uk/pages/technical/spark_plugs_technical.htm
http://en.wikipedia.org/wiki/Spark_plug
http://www.purehonda.com/cool/spark.html
http://www.ngk.com/sparkplug411.asp

Colour analysis to help you chose which plugs to go for... http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm
http://www.seadoosource.com/sparkpluginfo.html

- rust at backside near back window
- cool water sensor

Massively helpful!! Just bought a Toldeo 1.8T 20v today and this stuff is golden, much appreciated.

thanks for posting this, I had trouble with my MAF a while back and practically took everything off, changed it and tested until solved problem. Might have solved it quicker with better knowledge... This might be worth getting posted as a quick reference guide feature on the site rather than hunting the forum for answers...

Thanks top guide

top thread

Out of interest in section 1, how do spark plugs cause high boost problems?

Great information.......Thank you very much!!......

02 sensor

Hi ladss in desperate need of help!

My emissions light has recently come up and i have vag comed it and it says its the lamba/02 sensor. I know thiers two sensors but dont know what one goes where. GSF have told me the sensors on the car are the wrong way round but i keep telling them the one nearest to the engine has a very small wire and would not be big enough to go to the one nearest to the exhaust.

Does anyone know if the ones with the small dots on the sensor go?

Or does anyone nowhere the one with the slit in it goes?

As two ive got are the same size in length however the sensors are different!!


anyhelp appreciated

cheers mark

Nothing like abit of knowledge

Great Thread Cheers For The Info

Fuel pump Relay – The fuel pump relay is located under the driver’s side kick panel. Remove the lower panels to gain access to the relay box. When the fuel pump relay goes bad it will trigger many fault codes with electrical shorts to ground. The fuel pump relay is also used to turn on the injectors, and will show injector short to ground failures. If you open your door you hear the pump kick on, if the pump no longer kicks on, and you experience these codes repeatedly, replace the fuel pump relay.

This sounds like my fault, which replay is for the fuel pump relay mate?

thanks pal ive had a boost leak prob but not now thanks fella

misfire wount go away

I have been having a intermittent misfire probs on my 2005 lcr 225 for sum time now. it happens on high load around 5000rpm and the warning light will flash when the engine sblutters but dose not stay on. I have change the following parts; 4 coil packs , irudim plugs , egt sensor, 2 lambda sensors. by playing about I noticed that if I disconnected the plug of the pre cat lambda sensor the misfire wont occur but em light will stay on. I am looking to revo stage 1 the lcr but know ther is no point with it misfireing or with lambda sensor disconnected . eny thouts wil be much thankfull

Cat maybe??

hi, thanks for message. got a decat on it, had the problem before I put it on. getting a vag com put on this weekend

great thread

good read

Re eml

I have a lcr with revo stg 2.. my lamber has been mapped out bud . no eml

aledglyn said:

I have been having a intermittent misfire probs on my 2005 lcr 225 for sum time now. it happens on high load around 5000rpm and the warning light will flash when the engine sblutters but dose not stay on. I have change the following parts; 4 coil packs , irudim plugs , egt sensor, 2 lambda sensors. by playing about I noticed that if I disconnected the plug of the pre cat lambda sensor the misfire wont occur but em light will stay on. I am looking to revo stage 1 the lcr but know ther is no point with it misfireing or with lambda sensor disconnected . eny thouts wil be much thankfull

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