Strange Intermittent Spark/Starting T25 1.9 DG 1988

[Dentman]

Hi All

Strange Fault on a 1988 wbx Dg 1.9

This has been mechanically fine for the last 2 years but the other day stopped to let someone out, pulled away and it just stopped! Thought ran out of fuel but no judder etc. added 10 ltrs still nothing.
Thought Fuel nope (checked)
got a tow tried bumping no joy. Not a cough??

Thought Spark?
This is where it gets odd? No spark from king lead or Plug lead so thought COIL? Done ohms check on both primary and 2nd windings both within tolerance!

Pulled Hall connection from dizzy and checked for power and earth (yep) then tried earthing centre contact and earthing king lead from coil (YES Spark) thought Coil / Hall Sender or Control unit!

Interesting bit! I pulled the power off coil (15) and earthed King lead then flashed power lead on coil (15) and got a SPARK!! Did this 6 times reconnected and checked for spark from plug and king lead and YES got spark.

Started and ran for 20 mins then stopped same fault? Repeated above and it started again for 5 mins? Changed coil same happened again (not coil)

So Ignition Control or Dizzy??? or Something Else???

Any thoughts!!?

[itchyfeet]

could be a bad connection or broken wire on coil, earths under coil or earth on head by dizzy, even if they check ok with a multimeter a coil draws a few amps and a broken or corroded wire can measure ok but fail with vibration, heat and current.

I'd cut off and remake spade connections to coil and ring terminal earth to head, clean up earths under coil.

[ajsimmo]

Could be the connection on the side of the dizzy, either the 3pin connector itself or the thin wires to it inside the dizzy body which can be bent very tightly and can break on the bend.

[ghost123uk]

Unless I read it wrong, it sounds like the ignition amp breaking down when hot to me. But I may have read Dentman's test list wrong

[ajsimmo]

Pulled Hall connection from dizzy and checked for power and earth (yep) then tried earthing centre contact and earthing king lead from coil (YES Spark)

Probably not ignition amp then, as it works when earthing centre pin at dizzy end of loom. Saying dizzy wiring or hall sender to me. Or I've had a couple in that have a break in the middle of the loom, start and run ok but when you move the wiring the engine cuts out. Basic wiggle testing whilst running finds that one though, and I'm sure you've done that!

[Dentman]

Thanks for the suggestions.

Have cleaned the earths for the coil and the engine head, Not tested with meter!!? Also glad i changed gearbox earth earlier in the year. Turns over like a dream!!

Also have done the wiggle test in the engine bay! anywhere else???

When playing about I pulled one of the power spades connections and strike on the coil supply, whilst holding king lead from the distributor to earth, on the cap metal clip!

Ignition on and Strike it 3 to 6 times!! Hey presto have spark.

Then runs for 45mins or 5 mins then no spark!!????

Repeat the above and it runs!!

When this has happened have tried replacing coil and distributor independently and no spark!!

Fault has happen again (ran for 2 mins) and just tried Ignition Control Unit and it started straight away without flashing coil so Think it could be this?? Testing again.

[ajsimmo]

I wonder if this ever got fixed?

[ghost123uk]

I wonder if this ever got fixed?

3 1/2 months ago = I would hope so !
What are you doing trawling old threads, ya can't be bored with the amount of backlog you will no doubt have = get back to work !!

[ajsimmo]

LOL you are so right, John. I have a shed full of vans, and a waiting list, but I also have lunch

Just swapped a dizzy due to similar problems, and all's still well after 3 cold-to-hot roadtests. But there's always that tiny niggling doubt with these intermittent faults...

[ajsimmo]

I wonder if this ever got fixed?

3 1/2 months ago = I would hope so !

Well if it was, surely the OP would have dropped in to say so...

[Dentman]

Sorry for long long delay!!!

Yes fixed!!!

It was the Hall Sender, replaced with 2nd hand and this lasted for 3 months then failed again. Same thing I checked earth's etc..

So I replaced coil and hall together and hey it fixed it. Thought it my be the 30 year old coil burning out the hall? I tested it and all good!

[ajsimmo]

Thanks for the update

...still smiling at the 14 month road test before you're convinced it's fixed!

[Dentman]

Thanks for the update

...still smiling at the 14 month road test before you're convinced it's fixed!

If it's not one thing it's ANOTHER!

Since this issue, I have rebuilt Carb (easy)

New rear brakes, and this week Radius bushes (welding etc) and all other front end bushes.

Think I am slowly making a new van.

Still smiling but it does drive well at the moment.