mk1 gti starting head ache 1984 cabby kjet system help

ive had gtis for years on and off and know my way round them I don't like to post on here until ive exhausted my knowledge and I'm knacked now !
ive got it running great starts good from cold revs freely
set timing
set idle
mixture is in the right ball park
but every now and again its hard to start without a little throttle
I would like it to start on the key with know need to use the throttle but can I devil get it to do this
cold start valve is all working
injectors aren't dripping they spray nice
new plugs fitted
aux valve seems to do its job
sometimes it will crank over for ages and eventually start and sometime it just sarts straight up doing my box in at mo
like I say if I give a little throttle it starts straight up
so its not getting enough air or fuel on start up
fifth injector  works as it should
I don't know where else to go with this
any help would be great

on a plus not its looking clean  

You might need to pressure test the injection system to see if it's holding fuel pressure when switched off, might be the accumulator?

When you have to crank the car to get it to start does it run lumpy when 1st started?

tried cleaning the warm up reg? also I would check the metering flap is moving smoothly and at right level and try cleaning the plunger mech with carb cleaner. the accumulator normally gives issues with hot starts if broken

mark1gls said

You might need to pressure test the injection system to see if it's holding fuel pressure when switched off, might be the accumulator?

When you have to crank the car to get it to start does it run lumpy when 1st started?

had time to have another look today
accumalater is working ive took the small grub screw out of the back and its not leaking also I emptied it of fuel and could hear the spring inside decompressing
so that's ok
removed the non return valve on the pump all ok only lets fuel past one way when under pressure  

sporttrucker said

tried cleaning the warm up reg? also I would check the metering flap is moving smoothly and at right level and try cleaning the plunger mech with carb cleaner. the accumulator normally gives issues with hot starts if broken

thanks for suggestions sporttrucker
today ive had the injectors out they all spray fairly nice when the pumps running and the meterhead flap is lifted when the flap is let back down the injectors shut off with no drips
when the pumps shut off I have pressure and the fuel inlet union just after the filter which is good.
but not at the injector unions is this correct??
as soon as the pumps switched on theirs loads of fuel pressure from the injector unions at the top of the metering head
and at the injectors themselves fuel is their instantly as soon as it cranks

as I said above the injectors are working fairly good but they are the originals that makes them over 30 year old and I guess could be too weak when the engines cranking ??
when running it revs and idles really good
I'm holding off buying new injectors as they don't leak and spray a fine mist not like a Saturday we up the wall

running out of ideas
coldstart valve is working and the aux valve is doing its job

sporttrucker said

tried cleaning the warm up reg? also I would check the metering flap is moving smoothly and at right level and try cleaning the plunger mech with carb cleaner. the accumulator normally gives issues with hot starts if broken

I haven't looked at the warm up reg yet but ive noticed that the engine when cold doesn't idle high like 1400rpm and them drop back down slowly to 1000rpm when warm like some of the gtis ive had
is this the job of the warm up reg
I always thought that was the aux valve??

vwoldmad1 said

sporttrucker said

tried cleaning the warm up reg? also I would check the metering flap is moving smoothly and at right level and try cleaning the plunger mech with carb cleaner. the accumulator normally gives issues with hot starts if broken

I haven't looked at the warm up reg yet but ive noticed that the engine when cold doesn't idle high like 1400rpm and them drop back down slowly to 1000rpm when warm like some of the gtis ive had
is this the job of the warm up reg
I always thought that was the aux valve??

I had similar issues with my Golf starting up when I bought it.. I resolved other stuff before I looked at this.. it would start but needed revs for about 20-30 seconds, if that.. then it would be ok & even on a run I would have the slightest miss. I tested the WUR power & it was spot on.. tested the 5th Injector too.. fine. So I took off the WUR & took it apart - not clean at all, should be spotless. Took it apart, cleaned it with injection spray, put it back together with a new piece of bespoke viton rubber.. cleaned the gauze with the spray as well, connected the fuel inlet /outlet & torqued up.. low & behold.. great! It worked! Found it to be responsive & running well.. on pulling up at lights or a junction the revs were up & down..   got it sorted for a tune, the tuner said he smelt petrol as soon as a pulled up, did a few adjustments, got the mixture right & it was sorted! Took it for a spin & it was fab! Getting over 40mpg too! Reading up on things (& by default ) the WUR has a big part on controlling fuel pressure throughout the k-jet system.. when cold it tells the meter to push more fuel etc, 5th injector cuts in for about 8-10 seconds, when the car is warm it starts without the 5th injector, there’s a bimetallic strip in the WUR which is temperature controlled which is doing activated for the pressure.. I renewed gaskets etc to get it running well, did renew the meter to airbox gasket too, only about £14, did take FD off too & cleaned with CRC spray, under the plate (surprising the build up under the plate) & around the plunger - used this spray as it’s non residual like other sprays. Hope this helps.


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wow

Deandubya said

vwoldmad1 said

sporttrucker said

tried cleaning the warm up reg? also I would check the metering flap is moving smoothly and at right level and try cleaning the plunger mech with carb cleaner. the accumulator normally gives issues with hot starts if broken

che

I haven't looked at the warm up reg yet but ive noticed that the engine when cold doesn't idle high like 1400rpm and them drop back down slowly to 1000rpm when warm like some of the gtis ive had
is this the job of the warm up reg
I always thought that was the aux valve??

I had similar issues with my Golf starting up when I bought it.. I resolved other stuff before I looked at this.. it would start but needed revs for about 20-30 seconds, if that.. then it would be ok & even on a run I would have the slightest miss. I tested the WUR power & it was spot on.. tested the 5th Injector too.. fine. So I took off the WUR & took it apart - not clean at all, should be spotless. Took it apart, cleaned it with injection spray, put it back together with a new piece of bespoke viton rubber.. cleaned the gauze with the spray as well, connected the fuel inlet /outlet & torqued up.. low & behold.. great! It worked! Found it to be responsive & running well.. on pulling up at lights or a junction the revs were up & down..   got it sorted for a tune, the tuner said he smelt petrol as soon as a pulled up, did a few adjustments, got the mixture right & it was sorted! Took it for a spin & it was fab! Getting over 40mpg too! Reading up on things (& by default ) the WUR has a big part on controlling fuel pressure throughout the k-jet system.. when cold it tells the meter to push more fuel etc, 5th injector cuts in for about 8-10 seconds, when the car is warm it starts without the 5th injector, there’s a bimetallic strip in the WUR which is temperature controlled which is doing activated for the pressure.. I renewed gaskets etc to get it running well, did renew the meter to airbox gasket too, only about £14, did take FD off too & cleaned with CRC spray, under the plate (surprising the build up under the plate) & around the plunger - used this spray as it’s non residual like other sprays. Hope this helps.


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that helps loads dean
I have been though the complete system except the wur so I guess that's my next step
seems the wur plays the most important part of all when it comes to fuel pressure and delivery
will take it off and give it a good clean see what I find
fingers crossed I will sort it
thanks ever so mucho for taking the time out
to explain things wur related

well took the wur off and it was really clean
stripped it down anyway and cleaned it good n proper
refitted it what I did notice is the pump seems to be a bit quieter and when started seems better and starts a bit better
gonna try starting in morn from cold

mind you from coldish not stone cold it starts and revs frelly straight away and idles about 1200rpm and drops to about 1000rpm when warm
maybe I'm asking too much of a 30yrs plus car
its running good enough I reckon if it start from stone cold in morn I'm happy
thanks for all the help guys

did you clean under the disc with the 4 screws in?. there is a metal sheet under it that the plunger presses, if you take it off you can clean the gauze better and blow it through with compressed air

yeah did that was all spotless before reassembly
I think its ok now as if it was broken it would start from cold and when warm run too rich
that's what ive learnt anyway
it only function is to lean the fuel off by the bimetal strip warming up and closing a port in the regulator apparently  
I may be digging deep again and getting some new injectors as there not great and must be 30yrs old by now  

coldstart valve works
thermos time switch works
aux valve works
timings spot on
new plugs leads coil dizzy cap ect..
wur must be functioning but no pressure gauges to  check
injectors are borderline