Kjet Pop then dead

I just broke down in a semi safe spot. I didn't get around to adding breakdown insurance and RAC is £150.

Basically driving along as normal and there was a sort of pop/bang sound from the engine, and it conked out. Not instantly, but after a few seconds it gave up. The fuel pump stills sounds with ignition, starter turns, but there's no sign of anything happening.

Should I just pay up?

I've left the side light on. Think the batt will last night?

Managed to tow my car back with a Land Rover (Sorry RAC).

Anyone know of a good thread with usual k-jet dianostic steps? Can't seem to find one.

Are you sure it’s a fuelling issue?
I would check compression in case the timing belt has snapped, check for fuel pressure and check for spark.
Go from there ?


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It's a long thread, but there are plenty of suggestions in here.. https://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=helllllpppp%2Fk-jet-experts-please

Haynes manual also has some basic test info in it as well.

There is a FB group - Bosch CIS Wizards that might be a good reference.

jazzydog said

Are you sure it’s a fuelling issue?

No. Didn't think it was.

jazzydog said

I would check compression in case the timing belt has snapped, check for fuel pressure and check for spark.
Go from there ?

Okay, thanks

paceman said

It's a long thread, but there are plenty of suggestions in here.. https://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=helllllpppp%2Fk-jet-experts-please

Haynes manual also has some basic test info in it as well.

There is a FB group - Bosch CIS Wizards that might be a good reference.

Thanks

If it was fuelling the engine would just die away. The fact that it gave a pop/bang, sounds more like it could be ignition related - (ended in a misfire ) and something has given up the ghost suddenly.

Good luck, hope it's not too serious…

Go back to basics;

pull a lead off and does it spark when held near the block when cranking?

Pull an injector out, does it spray petrol when cranking?

So just pull one of these off, and hold it near the block while trying to start it?






 

Yes but look likes a 16v so not factory and poss lots of none standard things going on with wiring, fuse box, ign  and fueling.

Best Dragons Den voice, "I'm out".

the_whip said

So just pull one of these off, and hold it near the block while trying to start it?






 

Early-1800 said

Yes but look likes a 16v so not factory and poss lots of none standard things going on with wiring, fuse box, ign  and fueling.

Best Dragons Den voice, "I'm out".

lmao,

 "Retreat!"

If it was a misfire issue it could be the ignition amplifier which sits in the scuttle tray at the back of the bay.

Mine packed up earlier in the year and made it impossible to drive, back firing pops and stalling constantly.

Once replaced - no more issues (for now!! 🙄)

The bang seemed to come from the engine bay, rather than the exhaust.

Anyway, I did some tests…
Spark plug smelled of petrol, and there was no spark.

I then did tried this (kinda guessing my way through):



I checked the resistances on the coil:




0.9 and 3.12K seem out from what they should be. Enough to stop the engine starting completely?

Thanks for any advice.

For anyone following this is the future…

I picked up a second-hand coil on eBay. Resistance was above 7K so within proper range. Popped it in and engine started instantly.

Coils are basically a step up transformer, and as in all electrical things can go bad. They can dry out and arc between windings, I have seen them blow the top off of them when that happens, other I have seen the Cases bulge out… Or have spark tracks on them…. The newer Coil paks are even a tad easier as if you look at the under neath and yours has clear epoxy, you can see it chared, cracked and ugly…if it has black Epoxy, then you look for it to be less shiny, or cracked, holed….

Great post with conclusion.

Here is a quick tickle test by my Friend Ron….

No spark?
Here are some spark tests, post your results.

Put the business end of the coil wire where it can arc to ground without shocking you or starting a fire. Ignition switched on for these tests.

With the plug removed from the Hall sender, with a paper clip or whatever as a probe to the center wire (green/white I think) of the Hall sender harness plug, 'scratch' or 'tickle' that center wire to ground, you should see sparks.
Yes, Good spark every time.

Here, you've just tested, as a system, the entire ignition system EXCEPT the Hall generator itself.

While the Hall plug is in your hand, measure voltage across the two outer pins, I'm not 100% on this but I think it should be 10VDC. I think you've done this already.
11.25 V

Reconnect the Hall, back probe the center, green/white and connect your DVOM between center to a known good ground.

Slowly rotate the crankshaft by hand, as the shutter wheel alternately blocks/opens the Hall opening, voltage should go from ~zero to ~10VDC.

Hope this helps others in the future.

the_whip said

For anyone following this is the future…

I picked up a second-hand coil on eBay. Resistance was above 7K so within proper range. Popped it in and engine started instantly.

Well done. Note there are two types of coil, ballast and non ballast. One runs at 9-10v and 12v when cranking so you get 20% extra big spark for starting.

I think most VW ones will have been ballast since the early 80s? but they could have been mixed up when the engine conversion was done? If so that may be why the wrong failed when being run at the wrong voltage?