8v KJET wont start.

Hi,

Im nearly done with my vw camper conversion. engine in (mk1 golf gti, dx), rad done, plumbing done wiring done and i really thought i would be driving it now, but no.      

It just wont start on its own. i have spark, fuel pump runs, csv on. after trawling the search feature i have checked the basic stuff and have found if i slide my hand under the metering head and lift the plunger about 10mm with my hand it fires and runs first time. I can rev it so long as i keep the plunger up 10mm and sounds sweet, but it cant seem to hold it up itself. Ive taken the metering head out and cleaned it well, twice and it is free and light. I cant find a air leak anywhere. this is just doing my head in.     has anyone experienced this before on a kjet car? totally run out of ideas…

idle screw?

would that effect start up? it came off a car all working so i guessed it was fine.

Hi

It sounds like youre no pulling enough air through the induction pipework to lift the plunger .
The cold start injector should at least make it splutter & pull more air through  which would also help lift the plunger . could be the WAR ( warm-up-regulator) as well , which also helps lift the flap when its cold

any chance of a photo of a dx engine in a camper
cheers
baz

sburford said

would that effect start up? it came off a car all working so i guessed it was fine.

yes, if it is too far in.

here are a couple of pics.  quality is not great, damn iphone.






I have had to increase the length of the air pipe from metering head and inlet manifold.  Do you think this may have an effect on it?  i have checked and air is blown from breather and when supporting plunger and revving it i can feel it lift the plunger, but not sure if it is enough.  I could increase the idle screw and see not tried that.  i read that you can increase the fuel pressure with shims in the metering head.  would that help? i'd really appreciate your thoughts on it / what to try.

cheers

ive beeen giving this some thought this morning.  Im not sure if my battery is big enough for this block as it was the campers.  Its a 400cca but not sure of its age.  Am i right in thinking if its not tiptop then under cranking it could lose voltage to the pump and then the fuel pressure would drop and not be ablt to deliver unless i pull the plunger up giving it full fuel?  any easy check to rule this out?  what voltage should i expect on ignition, and under cranking?

Low battery voltage wouldn't explain why it doesn't continue to run once started.

Mixture screw - sounds like you're way out on it.

it did start and run fine once.  i didnt change anything it just caught and was fine.  stopped it and it wouldnt restart on its own. havnt managed to repeat it since.  When i start it holding the plunger up my hand is in the airbox and by the time i pull it out and shut the lid it stalls, and wont start again.  im leaning to fuel pressure issue, is not voltage then maybe WUR?  but in truth im just guessing now have no real evidence either way.  Tempted to buy/rent/borrow a fuel pressure gauge to pressure test it.  any ideas where i can get one?

have you tried throttle wide open & continually turning it over for a min (it should turn over no problems with a healthy battery) , the theory being with the throttle wide open it will pull more wind through the metering head & lift the flap , if it does start hold it at 2000 ish revs for a while then if it conks out when you let the throttle go then its probably your mixture/idle adjustments or your induction pipework isn't perfect

The CSV only squirts fuel when turning over the starter as well for a max of 10secs approx
Only do the above if you're sure you're not getting enough fuel .its very easy to flood the engine as well on a K-jet might be wise to pull the plugs first & check there dry
cheers
baz

as paul says, you could well be out on the mixture. lifting the flap will add more fuel. so you could well be running too lean. try adjusting the mixture screw, remembering how far/many turns you have made, in which direction.

cheers loads people.  
Ive just been fiddling with the idle and mixture screws and bingo it started.  smells really fuelly but it doesnt have an exhaust yet so that cant help.  Revs nice.  need a gas tester and exhaust to set up properly.  i did move it  bit on the clutch and that made it run rough and wouldnt clear, so its not right, but it does run.

as a rough guide on the mixture, while running, ytun clockwise until she starts to hunt and take note of how many turns anticlockwise until she does the same. turn clockwise app, 1/3 of the amount of turns you came back. you should be near enough that she runs o.k.
important that you are very carefull not to push the mixture screw down when doing this. just make sure you remember how many turns

cheers for the advice, my next questions was about setting it up.  

i thought i read you shouldnt run the engine with anything in the mixture screw hole.  Is that not the case?  also is that all from warm or cold?

cheers

wooders said

as a rough guide on the mixture, while running, ytun clockwise until she starts to hunt and take note of how many turns anticlockwise until she does the same. turn clockwise app, 1/3 of the amount of turns you came back. you should be near enough that she runs o.k.
important that you are very carefull not to push the mixture screw down when doing this. just make sure you remember how many turns

When you say till it starts to hunt what does that actually mean?

cheers

when there is too much fuel or too little, the engine will begin to run rough/lumpy and want to stall. called hunting (for fuel/air)

you kind of need to adjust mixture with the engine running

Basically, hunting is when the idle speed seemingly inexplicably wanders up and down. Hunting is due to open loop dynamic characteristics when a small change occurs during idling. Later cars used ISV, later still more sophisticated engine management possibilities like ignition advance at lower-than-idle RPM.

Since idle stability correlates poorly to mixture, its an inaccurate way to set the mixture.

it is indeed inacurate, but the dx will run at anything from 0.3co to as much as 5.0co, so it will get the engine running well enough to drive. i wouldn't suggest for one minute that the co will be set correctly doing this.