Fuel Filter

Ive been struggling to get my 1.8 gti running properly now for a while, and have been searching old posts for clues - stumbled something about different sized fuel filters.  

As my engine was incomplete when i bought it i dont know what size came off, but ordered one from gsf - its about the size of a coil, yet ive seen some much bigger - could this be causing the low fuel rate/pressure i seem to be experiencing??

shouldn't do no. post up your symptoms and all you've done in order. too much info cannot be given. every little detail and then maybe we can help.

Later cabbys had a larger fuel filter, simply for cross-model parts commonality reasons.

its had:

new pump

new relay & fuse

New main fuel filter

New plugs, rotor arm, dizzy, air filter

new cambelt and tensioner

timing set by light

Cleaned tank filter

checked meter head with a second known good one

cleaned micro filter in wur

checked continuity across  wur and AAV

All it does is spin over, it has fuel, compression and a spark.

The only way it will start is if i lift the plate on the meter head ever so slightly, and hold it there until engine is red red flippin red hot then it will sit at idle by itself if i back off slowly

Any throttle at any point when warming it up, and the engine starts to struggle, unless i gradually increase it until 2nd butterfly opens then will rev resonably freely.

Once hot though it runs ok, well I say ok - only ever driven it about 30 yards in a straight line!!

Its as if i just aint got enough fuel when cold, which by me increasing fuel by lifting the plate gets it running, but then its too rich/lean to rev?

So you've not set the mixture?

Failing that, new WUR + set mixture.

no not set mixture - dont have a co meter - so dont want to play too much with that incase i go way out and can never get it back.  got head off phatts who had it running fine on a cabby before sending it to me so should be there or there abouts shouldnt it?

rossirvine said

no not set mixture - dont have a co meter - so dont want to play too much with that incase i go way out and can never get it back.  got head off phatts who had it running fine on a cabby before sending it to me so should be there or there abouts shouldnt it?

Well not really, mixture needs setting up when you put a new metering head onto a car, even if it worked fine on another car. You need to get the mixture set properly, there's no shortcuts.

righty ho - well by the fact i need to lift the plate to get it running when cold then release it when its warmed up, can i assume the mixture is too weak - ie richening the mixture on start up with the plate lift, then its running lean when warm?

onlt ask because i would need to get it running near enough to get it to a garage with a CO meter as i dont have cash to shell out on one for me self

To do this i just need to tweak the 3mm grub screw slightly clockwise yes? and how much is slightly - ie in degrees, monkeys tails or any other relevant unit?

I've never heard of that test to check if mixture is too weak or rich - but I suppose it indicates yours is weak.

Turn it clockwise….but I don't know how much by. Without the meter, you're guessing…..may as well guess in 1/8 turn increments, I don't know??? I'm not good at guessing….

well it was kind of my own test i invented - when 1st delving into this i thought i might have false air, hence not having enough of a vacuum to lift the plate - just a stroke of luck really that it seems to have turned the fuelling issue up!

cheers paul will give it a go when i get back from work tommorow

hey ross, just to let u know, if u read my can u help thread, im having exactly the same probs with my cabrio……..we've tried everything all the same replacements as you and done a compression test which is ok??? i havent done the mixture yet tho??

ITS ALIVE!!!!

gave it two, yes two full turns richer, then it fired sat just over 1100rpm til warm then settled at 900! at last the missus cant moan that it doesnt run!!! cheers everyone whose helped!!