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K-Jet Experts - please help (latest update Pg 6!!)

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cedar said

Pistol - Do you mean you've tried to start it with the No 17 relay in place and it still won't go?



No Cedar, I've just cranked it over with relay 17 fitted (plugs and coil HT lead disconnected) to see if anything came out of the 5th injector. 

I'm definitely getting fuel round the system as I've still got the pressure gauge installed between fuel distributor and WUR.

I've just ordered a couple of used 5th injectors off eBay (on the basis that at least 1 of them will be good!!).. Think I need to sort this before proceeding now, as if it is spraying fuel it should at least fire up.

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17/18 relay will bypass any issues with the kjet fuel relay, obviously it wont help if you have no spark but its really handy for doing pressure tests, 5th injector etc plus when looking at wur/aav voltages etc.  you can drive the car like this even, though the pump wont cut out if you crash so its not safe long term

if you get a spray of fuel out of the 5th injector while cranking with the green/white wire earthed but not when thermoswitch is connected then the thermoswitch is bad. if you dont get any spray with the green/white earthed then the 5th injector is bad, or fuel isnt getting to the injector for some reason.

if the 5th injector isnt working then it will result in harder starting and its not going to help if the engine hasn't been run for a long time

worth a read thru my 16v troubleshooting thread, all of the basic kjet tests still apply just ignore the extra 16v bits:
https://www.clubgti.com/forums/index.php?threads/how-to-check-repair-and-tune-your-mk2-corrado-1-8-16v.195423/

I would double check the height of the metering head flap for example. other issue is if non of the parts came from the same car or have been refitted after an extensive restoration job they may be too far out of adjustment to start your engine, I've had issues swapping around 16v metering heads in that case it was a case of trial and error on the mixture and idle adjustment screws till I got it close enough to start then i could fine tune from there.

to rule out fueling issues you can spray some easy start, brake cleaner or similar down the throttle to see if you get any signs of life from the engine.

oh and worth double checking the timing, can use my digifant guide for reference just obviously ignore all the setup procedures:
https://clubgti.com/forums/index.php?threads/how-to-diagnose-and-tune-your-mk2-digifant-gti-8v.124949/

the cam sprocket is easy to fit backwards then non of the cam timing marks line up

Hello my name is John and I'm a dub addict.



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It will go in the end.
A quick check of the timing is set the centre of the rotor arm against the notch in the distributor case, take out plug No1 and the piston should be at TDC, take off the oil filler and the lobes on the cam on No1 should both be looking up at a similar angle.

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cedar said

It will go in the end.
A quick check of the timing is set the centre of the rotor arm against the notch in the distributor case, take out plug No1 and the piston should be at TDC, take off the oil filler and the lobes on the cam on No1 should both be looking up at a similar angle.




Yep, all done and it's good. I don't have a timing mark on the cam pulley as it's a Schrick vernier fitted, but I've marked the tooth that corresponds to the inner timing belt cover point at the rocker. I'm confident the engine timing is spot on. I do know ignition timing is 6deg BTDC, so I may move distributor slightly to align with spark on the flywheel diamond mark.

I'll have to take a break from the car now as work requirements are taking over, but I'll keep this thread updated until finally resolved.

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So my problems continue.  Had another morning looking over the car.  I bought a couple of used 5th injectors off ebay, so fitted one of those and sure enough I have fuel now on cranking the engine.  Great I thought, that must have been it.  Put everything back together, fit the plugs and re-connect coil leads.

Bloody thing still won't run.  It fires initially, then coughs/splutters and dies.  

Re-checked the timing and it all lines up.  Pulled all 4 injectors and ran fuel pump using relay 17, I'm getting good spray pattern and virtually identical volume from each of them over a 30second period with the airflow plate lifted to the max position.

I checked the main earth connection to the chassis leg, took that back to bare metal in case it was poor earth, but no difference.

I hooked up timing light to HT lead and I am getting spark pulse ok.  The rev counter is not working, makes me wonder if the coil could be iffy somehow.

I'm at the end of my tether here, the only other thing I can think of is to send the metering head off the KMI for a full overhaul, but I believe that could be mega money.

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I had issues a few months back with struggling to start after the car had been sat for a few days.
I switched the coil over for a new one and instant fixed the issues. Well worth a go if you have a spare one kicking about.

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If you can get hold of a coil try one as above but it does sound like a fuel problem, it must have a spark to cough and splutter, does it backfire.
Have you tried cranking it with the No 17 relay in place of the fuel pump relay.

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cedar said

If you can get hold of a coil try one as above but it does sound like a fuel problem, it must have a spark to cough and splutter, does it backfire.
Have you tried cranking it with the No 17 relay in place of the fuel pump relay.





All the start attempts today were with relay 17 installed so fuel pump running continuously with ignition on. It backfired once or twice. I played about with the mixture screw quite a bit to see if I could get it going, but no joy. Haven't touched idle screw yet but didn't think that could prevent starting completely.

I'll buy a coil and see but think I'm clutching at straws with that one. 

If I pull the 4 injectors and plug the holes, I take it I should see fuel spray during cranking? So if they don't fire, then is it pointing towards metering head?

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If you are getting a good and equal spray pattern when you lift the air flap when the pump is running then surely the metering head is okay.
I once built a 2.0l scrapyard engine, cost me £20, and couldn't get it to run, after exploring all of the difficult to do checks I realised the plug leads were reversed, it ran so well once I had put them right.
Just once more go over all the timing checks, rotor arm aligned, No1 on TDC and No1 cam lobes pointing up at similar angles.


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to complicated send me your number or ring
07739608140 cheerspaul

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

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if you dont have a rev counter feed to fusebox this will stop the kjet fuel relay working, but the 17 relay trick will bypass this. fact it still doesnt fire could suggest spark issue which would also explain rev counter, or perhaps rev counter is a separate issue.

the pulse seen by the rev counter is the spark trigger signal from the TCI-H unit in the scuttle, it would still give you a jiggly rev counter while cranking even if the coil was dead, unless the coil had some kind of internal short to ground on the negative side I guess…

anyway have a look over the spark system now. check all the wiring from distributor to the TCI spark module, check dizzy/tci pins are straight, tight and fully pushed into the plug. peel rubber boots and check wire crimps in the back of the pins. Look at spark module wiring to coil and back to battery negative.

try another module if you can, mk2 golf ones all the same so plenty available.  check the coil is correct for the type of leads & cap used, and also make sure its correct for your ignition system. the plug lead fittign to coil/dizzy cap changed around 1987 from open hole -> wing to pin -> clip and the electronic ignition coils are different to points.

Hello my name is John and I'm a dub addict.



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spark module pinout:
1 - coil negative
2 - battery negative
3 - dizzy pin 1
4 - coil positive
5 - dizzy pin 3
6 - dizzy pin 2

you should see 12v if you probe between pin 4 and pin 2. with ignition on you should see voltage between dizzy pins 1 and 3, some manuals suggest 5v some 12v.

next plug dizzy back in and peel the boot off the back of the spark module. put your multimeter between pins 6 and 3, you should see a voltage pulse while cranking. if its going too fast to measure get a helper to turn the engine over by hand instead

Hello my name is John and I'm a dub addict.



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Cheers John, I'll go through all these checks.

I've hooked up a timing light to plug lead 1 and the coil HT lead and I am getting the light flashing whilst cranking, that's what made me believe the spark side was ok.

I've physically pulled no. 1 plug and with the lead attached, there is a visible spark whilst cranking (hard to say if it's weak or not). I’ve just ordered a new Bosch ignition coil to rule that out anyway.

You don't fancy an all expenses paid weekend break to Northern Ireland do you???  ;)

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probably ok then tbh, did you try the other 3 leads/plugs?

Hello my name is John and I'm a dub addict.



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rubjonny said

probably ok then tbh, did you try the other 3 leads/plugs?

Pretty sure I've had it on all 4 plug leads, can easily check again.
So I'm pretty much back to fuelling then.

Is there a starting point for setting up idle & mixture screws? I've tried to adjust mixture with the pump running to the point where fuel starts leaking from injectors then backing it off again a little bit til they stop. I've also had it fully leaned off. I know a small amount is supposed to make a big difference, so is it completely trial & error to find the sweet spot?

And if I pull injectors again, am I right in thinking that they should start spraying whilst engine is cranking over if I have relay 17 installed for continuous fuel pump running?

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when fitting unknown parts it is just a case of trial and error till you can get it to fire, had the same pain when swappign bits on my 16v.

the only tie the main injectors should spray is if you lift up the metering flap plate, at rest nothing should come out at all.

if you've gone through all of the checks in my 16v kjet troubleshooting guide above and everything checks out all thats left is either air/fuel adjustments, compression or spark

Hello my name is John and I'm a dub addict.



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You seem to have covered everything but going back to the most basic of basics, if you pull one or more of the plugs out after a failed cranking session are they wet and does it stink of petrol???

Double triple and quad check the leads aren't mixed up or all out of sync by one position. Wasted half a day on mates mini that he'd swapped the leads for new ones but put 12 o'clock at 3, 3 at 6 etc. Everything looked and checked out fine, fuel, timing, big fat sparks etc (compared to dizzy on his spare engine the leads matched, one engine dizzy was fully adjusted clock wise and the other fully anti clock wise so the lead positions from cap to plug location look the same….) it span over just fine and occasionally coughed and sputtered with the odd back fire for good measure……

1983 Mars Red 1.8 Golf GTI
1987 Alpine White 1.8 Clipper Cabriolet

The trouble with doing nothing is that you never know when you are finished.

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they will not stink of fuel the problem is
no fuel pressure no matter if the timing
is 180 out it would bacckfire or make an
attempt simple internal combustion engine
i.c.i.e

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

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rubjonny said

spark module pinout:
1 - coil negative
2 - battery negative
3 - dizzy pin 1
4 - coil positive
5 - dizzy pin 3
6 - dizzy pin 2

you should see 12v if you probe between pin 4 and pin 2. with ignition on you should see voltage between dizzy pins 1 and 3, some manuals suggest 5v some 12v.

next plug dizzy back in and peel the boot off the back of the spark module. put your multimeter between pins 6 and 3, you should see a voltage pulse while cranking. if its going too fast to measure get a helper to turn the engine over by hand instead

I checked this stuff out and with ignition on, I have 12v between pins 4 and 2 on the TCI, I also have 12v between pins 1 & 3 on the dizzy connector.

When hand turning engine, I'm getting voltage pulsing between 0 and 6.4V.

I've ordered a new coil and TCI module anyway.

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I made a little progress today,  I changed the TCI module for a new Hella unit from ECP, and then realised I had no spark at all.  Refitted the original unit and I had spark again.  Very weird, and not exactly a cheap part either.

I got the car to fire up and keep it running by feathering the throttle pedal gently.  It wouldn't idle at all, and it also would not rev up. I hadn't changed anything at this point other than fiddling with the mixture screw.

The exhaust was initially very smokey (blue smoke), but I think that was mainly burning off the oil I had put down the cylinder bores for the compression test.  I also had a small heart attack when there was lots of smoke in the engine bay, but then realised this was just all the newly painted parts baking off a bit.

I've removed the pressure test kit as I am happy that the control and system pressures are correct.  If the car won't rev, won't idle and on the last occasion was backfiring whilst turning over, where should I go next?  Is it too lean, roo rich, is it the idle screw that needs to be adjusted, or should I try to get a timing light onto it?  If I could just get it running enough to idle, I can start to make tweaks here and there, don't want to go changing lots of things and go backwards again.

The rev counter is also working, so that was a red herring.

I think I'm going to go back over all the engine timing for another time, the bit that is niggling me is the vernier camshaft sprocket has no timing mark like the original, so I used feeler gauges under the cam lobes to confirm they were both fully closed (i.e. both pointing up the same amount, valves fully closed).  I'm just wondering if that is reliable enough or could I be a tooth out.

Last edit: by Pistol

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