ABF on K-jet - setting up & troubleshooting? Fixed and MOT'd!!!

Cheers - will have a read later. I did print out a guide to k-jet yesterday, same one I read years ago when my green Mk2 was playing silly buggers, that was a knackered WUR in the end too! I must try and work out how all these bits work together again, used to know it inside out at one point.

Mike - yes, the heater element is fine, I'm sure I tested that. In any case it should work without the heater, albeit much slower to warm up but should get there in the end.

Yes, the allen screw seems to pre-load the bi-metallic strip to some degree to set the starting point for the control pressure when cold I expect. It's fairly basic really how it works, as you say, could be that the strip has given up bending to and fro after 20 years of use!

 

sure i have a spare metering head in my garage. i'll take a look tonight. should have that bolt in there.

 

Where on the strip does it contact? The green pad? Maybe you could try taking the strip of and re-bending it, as a temporary fix...or stick a washer or two under the nut end?

 

Someone selling a 16v WUR on here:
http://www.clubgti.co.uk/forum/showthread.php?t=165225

Gurds

 

Hi
What is your definition of 'control pressure' ?
What is the pressure at the injectors called ?
Surely higher pressure at the injectors will be a richer mixture.

 

Read this, answers your questions.

http://www.auto-solve.com/mech_inj.htm

Was also posted earlier on this page.

Gurds

 

Stu I never realised you wanted me to check my wiring, my bad. Sorry to see its still going on.

It seems you have tried everything!

Was thinking it might be time to swap some major components across from your other valver and slowly return them to the original parts until you find the problem?

The wiring to the fuel pumps doesnt look good, thought about replacing it?

wouldnt be too hard as all your interiors out.

 

didn't tubs also say that the abf head has the dizzy bolt holes in a different place to the KR? sure vince said he re-drilled them sometimes

might be worth a look

 

The ABF only has one set of dizzy bolt holes, rather than two on the KR/9A type, so it's possible that you'd need to drill & tap another set to get the timing right. I think Stu has got the timing set though.

 

Cheers lads, all the help and offers of parts are much appreciated.

I've now sorted a spare metering head and WUR which are on the way thanks to Ade.Mk1 on here, so I should have all the parts I need to put this right soon.

Hi, I think you are confusing the system pressure with the control pressure. System pressure is the pressure of the fuel after the pressure regulator valve in the metering head, around 5 bar is what it should be. The control pressure is always less than this as it's basically system pressure minus what is bled off and returned to the tank by the WUR.

The control pressure is what acts on the plunger in the metering head to determine the mixture. Low control pressure = rich mixture, high control pressure = lean mixture.

As above, that link is very helpful in explaining how k-jet works.

No worries, Jamie checked the coil connections for me and they were ok... got a nice new one on there now anyway and tidied up the wiring.

I'm not keen on swapping any parts over from my other car to be honest, even for testing as at present the green Golf is my daily car and working very well to get me to work and back each day. I just don't want to break anything on that car and then have to use my other car for work as that's a thirsty old boy (325i) and would have me bankrupt in no time!

Yes, the fuel pump wiring does need sorting out but is doing it's job well enough for now to get the car running (hopefully!) It's on the 'to do' list... which is very long already!

 

Mike / Prof - I hadn't noticed to be honest about the dizzy bolt holes though now you mention it I think the ABF may only have one set as you say. I compared the dizzy position to that on my other 16v, which runs very nicely and it's set just the same compared to the head when at an indicated 6 deg btdc with the strobe so I think it's ok.

If you wanted some serious advance on the timing though another set of holes may be needed, will drill some if required but if I can get the bugger working properly at 6 degrees it'll do for now!

 

Yeah im sure you do but the way the k-jet works its a case of the more it demands the more it will give and with a few tweaks here and there you can get real good results.

 

But the "373D" bolt holes are the same reference points used on the KR/9A "373" heads.
If your K jet system is fuelling about right your should not have a problem with detonation with the dizzy in a sensible position.

 

The KR stuff will support 200 bhp - no need to change if it's all working properly.

 

Hi
Can you see any diaphragms ?
I suppose the diaphragms could be punctured.

 

Hi All, thanks for the replies as always

So, the saga continues... today this lot arrived - cheers Ade!




Firstly I removed the bit I needed from this spare metering head, the threaded union that had snapped. Thankfully this one was fine and did the trick. The replacement WUR wasn't drilled so thought I might as well before connecting it up, before:




After:




Hooked the 'new' WUR up on the car, with the fuel pressure gauge plumbed in again to read / set the control pressure. Warmed the car up to normal operating temp and watched the gauge, it climbed slowly and smoothly over about a minute and a half (a good sign!) and rested here at warm idle:




Hard to tell from the pic but it was around 42psi - a little low but not bad. So, I got the 4mm allen key and tweaked the screw in the back of the WUR clockwise, thankfully this WUR seems to adjust as it should.

After a bit of back and to, reading the gauge, tweaking the screw, reading the gauge again I got it to this - 48psi (again, not a great pic!):




I switched the car off, and leaving the pressure gauge plumbed in I disconnected the ISV and crank case breather, blocking the air box hole, and hooked up the timing light.

I checked the timing, it's still on the 6 deg btdc mark as it should be, set the idle to around 1k rpm and then set the mixture as per the guide Gary (GVK) posted earlier in the thread. Checked the control pressure again and it was fine. The idle was still quite lumpy whatever I did with the mixture, but not too bad.

So - after all that, how do you think it performs on the road...

 

... oh the suspense...


Well, the answer is that it's better, definitely better... but still nothing like right!

The car still makes a terribly rattley sound over about 4 or 5krpm, lacks a lot of pull on the road and struggles to pull second gear without sounding like the tappets are going to fly out through the bonnet!

For one thing, I think it's running too hot. For some reason the radiator fan seems to have decided to stop kicking in and the temp gauge will go to about two thirds (not good) before I give in and switch the fan override on. This could also partly explain why the stupid oil buzzer and light come on when you rev it too, even though the oil pressure gauge shows very good pressure?

Bah!

Anymore ideas boys? Surely with the combined brain power of the forum we can sort this?!?

Next thing I think I'll flush the cooling system and sort the radiator fan out, in case it is running too hot, hook up the oil temp gauge so I can keep an eye on that, and then see where we get to from there. Am I right in thinking that engines tend to run too hot with the timing too far retarded rather than advanced?

So, to sum up: Ignition seems fine, fuelling seems fine, timing seems correct... er... what else do you need to make an engine run properly?!?

This thing needs to get us to the 'Ring, and hopefully back - with plenty of laps inbetween in July!

 

Hi
Excellent tip.
Will it keep buzzing to give me time to open the boot, connect my stethescope to my ears and touch the boot floor.
Or will it buzz and then stop like the main pump.