T25 DG no spark

[stretch616]

I started to develop an issue with the engine intermittently cutting out towards the back end of last season and it seemed to be related to the ignition circuit. Faulty spade connectors was the AA diagnosis but eventually the van made it to the garage (on the back only an AA truck!). Diagnosis from the garage was the ignition module. After fitting the van started up first time and we thought happy days. However after letting the van sit for a week or so after this it now won't start.

Have removed a few of the spark plugs and attached it to the the end of the HT lead to see if there is spark and I'm not getting a sausage. I've measured the voltage coming into the ignition coil at 11v but then I'm a bit stuck as to how to test what could then be the issue.
Dizzy cap contacts are all fine. Replaced rotar arm as slightly corroded, ignition coil and a new set of spark plugs to be sure. Still nothing. In my inexperience I'm now placing the fault between the output of the coil and the output of the dizzy cap. How can I narrow the fault down any further? I've measured the HT lead's resistance @ 1000 ohms and the king lead @ 6000 ohms. Can't find anything to say whether this is in or out of spec and my multimeter can't handle a 40kv measurement.

Any input would be appreciated, me and the mrs are tearing our hair out at the moment!!
Cheers

Sent from my SM-G925F using Tapatalk

[CovKid]

As long as you've got thick rubber gloves, you can test the king lead the same as you would a spark plug - ie close to the body or engine. Whether you get a spark or you don't, you'll know where to look next

[bigbadbob76]

6000 ohms sounds high for a king lead.
I'd measure mine for you but there's a "pooh" load of heavy stuff piled on the hatch at the moment.
Hopefully someone will be along soon who can measure theirs for you.

[Oldiebut goodie]

11v doesn't sound good to me.

[stretch616]

Thanks for the replies so far.

What voltage should I be getting on the input to the coil?

Found a post on Brickwerks that says the king lead should measure 2k ohms. So I've gone for a new set of leads and we'll see where we go from there.

Sent from my SM-G925F using Tapatalk

[Oldiebut goodie]

Wait for a petrol guy to say but as a general thing on a 12v system I would expect to be seeing at least 12.5v.

[Smiffo]

Just a thought here - are your leads on your meter OK?

If you have 11v at the coil, and 6000 ohm resistance reading for King leads, is it not possible your meter leads have high resistance and giving false reading?

Try looping them to make sure you see near 0 ohms if I were you.

[Bubble Meister]

Some good advice so far. Check your meter leads are 0ohms. If the coil resistance is 6kohms then replace. If not Remove king lead and crank. If it sparks then the coil and engine position are good and it's probably the dizzy output. If it doesn't spark then wiggle the 3pin lead at the side of the dizzy and try again. If that doesn't work run a cable direct from the battery to the coil input (don't leave on fir long) and crank again with the king lead disconnected. If that sparks it's your coil power supply. If it doesn't work then test the dizzy position wiring - there's a vw guide on syncro andys website for the fuel and ignition system.

[stretch616]

Just checked again given the input so far. King lead actually measured 1kohm and ht lead at 6kohm. I put them in the wrong way round earlier. Happy that the meter is giving the right results and reading short when it should.

The battery is starting to tick over with less enthusiasm now as it's been used so much without the engine kicking in. So maybe that's the reason for a lower voltage into the coil? I'll put the trickle charge on it and see if that helps.

I'll check for a king lead spark next from the coil and report back. Thanks for the help guys, very much appreciated.

Sent from my SM-G925F using Tapatalk

[300CE]

Do you have anyone near you who could swap over the dizzy as could possibly be the hall sender. I had the same symptoms last year where the van would cut out and then backfire as it suddenly kicked back in. Eventually it conked out and wouldn't start. I had a load of spares in the van and changed the coil, ht leads, module and spark plugs to no avail.

Called the AA out and he put a spark plug tester on and you could see that one minute it was sparking the next it wasn't. She suddenly then started fine and I managed to get home. I borrowed & swapped over a dizzy from a kind member on here and it ran faultlessly - I subsequently bought that dizzy and she's been fine since.

I'm thinking it be the hall sender and will eventually replace this on the old dizzy which I've kept.

[ermie571]

I borrowed & swapped over a dizzy from a kind member on here and it ran faultlessly - I subsequently bought that dizzy and she's been fine since.

That's fabulous news

[300CE]

I borrowed & swapped over a dizzy from a kind member on here and it ran faultlessly - I subsequently bought that dizzy and she's been fine since.

That's fabulous news

Cheers Em - dizzy is still doing its job well!!

[stretch616]

Another update to the saga! We've checked the output from the (new) king lead and there's no spark there either. Double checked my voltage going into the coil and it's at about 11.5v. As previously mentioned, I've replaced this too just in case.

I've checked the 3 pin plug next to the dizzy. The connections don't look great in here I must admit, almost a bit corroded. I've cleaned up as best I could with a wire brush and still nothing. Is the next step the direct wiring from battery to ignition coil?

Sent from my SM-G925F using Tapatalk

[stretch616]

Stupid question time!! That 3 pin connector block doesn't look great and really could be an issue with some of the power getting into the dizzy. However we have tried cranking the engine with the dizzy cap off to check that the rotar arm was turning. Is it the power from the 3 pin lead that powers the turning of the rotar arm?

Sent from my SM-G925F using Tapatalk

[Smiffo]

Dizzy bottom pushes into engine and it is turned mechanically.
Check it is pushed down into engine block and bolted tight enough.

I'd post a pic but out and only on phone at moment