WUR issues?

[dirtydub]

hi guys ive got a problem with the warm up period after starting my car wondering if u have any ideas what this could be?
ive done some searching but not really come up with anything conclusive.
its normally valvers that seem to have this problem but mine is an 8v gti kjet pretty much same setup.

it always takes about 5 seconds of cranking before she fires and then runs rough for the first few minutes there is a smell of fuel during this period but once warm all is spot on and runs sweet, still maybe a little rich though not sure did 280 miles on 38 litres (£40) of optimax is that about right?

do u think this is a wur issue or maybe thermotime switch both are quite expensive and dont wanna replace one if i dont have to.

any help would be much appreciated thanks in advance 

Rich

[Ben Lessani]

Go do a fuel compression test at cold, hot, idle and 3krpm and post back - its the only way to conclusively know if the fuel system is misbehaving.

Are you sure the fuel smell isn't burning oil (stem seals), oil sitting in the bores will make it tricky to start and stinky on start.

[dirtydub]

yep positive its not burning oil recon head fitted 2k ago no blue smoke just smells rich on start up and fine after few mins.
do need to tweak co idle & mixture a little i think but wanna sort this prob before i do so everything is spot on.

sorry to sound thick but how do i go about testing compression on fuel system is it like setting up control pressure when doing wur mod?
ie connecting tester to metering head?

is there a way of testing the wur to see if it is at fault?

thanks for your help Ben

[Ben Lessani]

sorry to sound thick but how do i go about testing compression on fuel system is it like setting up control pressure when doing wur mod?
ie connecting tester to metering head?

Yup.

is there a way of testing the wur to see if it is at fault?

There probably is - but I don't know, without a fuel compression test, I would have thought the best you can do is see if the 5th injector is firing and swap out the WUR for a known working one.

[Bjork]

Hi mate. I'm having same prob.

Can you see excessive exhaust gasses too?

I've disconnected my WUR at the moment and it helps with the cold starting.

Getting a new one soon so I'll let ya know if that sorts it.

I'll keep checking your thread to see what you do too.

Good luck to us!

[dirtydub]

nice one, will have to wait till i get paid at end of month and get a compression tester to see whats what


will check cold start valve and will try and source a wur from somewhere not easy living in middle of nowhere and never seein any fellow dubbers  

anyone else thats had same problem or with any other suggestions? i would be very grateful

oh and can i use a 16v wur on my 8?

thank again Ben

Hi mate. I'm having same prob.

Can you see excessive exhaust gasses too?

I've disconnected my WUR at the moment and it helps with the cold starting.

Getting a new one soon so I'll let ya know if that sorts it.

I'll keep checking your thread to see what you do too.

Good luck to us!

dont get excessive exhaust gasses a little white smoke/steam as warming up but goes away after warm think thats just condensation.

will dissconnect wur and see if that helps will be good to know if ur new one sorts the problem

will keep in touch thanks guys

[rubjonny]

only way to test the wur is via fuel pressures, compare the control pressure cold, hot and warm up to the specs.  it should rise smoothly as car warms up too, if its jerky then wur at fault here.  the pins on the warm up valve should give around 20-26ohm resistance across them and 12v to the plug when fuel pump is running.

[dirtydub]

cheers rj very helpful will get testing soon.
roll on bank holiday weekend 

[Ben Lessani]

Bear in mind you want a fuel pressure tester - not compression tester. The kits for a K-Jet are $$$

[rubjonny]

there one up for sale for £40 quids on clubgti

here is a printout of the bentley mk2 k-jet pressure tests I have converted to pdf:
http://vwtech.no-ip.info/downloads/k-jetpressuretests.pdf

and here is an exelent k-jet tester manual I found, not specifically VAG but pretty much the same system:
http://vwtech.no-ip.info/downloads/k-jetfactorymanual.pdf