Spark help please - asap!!!!!!!!!!!!

[VSSECO]

Guys I need some deperate help with a spark problem here, the situation is this....

Drove about 150km this morning and towards the end of the trip I was on cruise control at 100km/h and the car gave a sudden jolt like the engine had died momentarily. I got off cruise gave it a bit of a rev, all seemed ok so drove on home.

An hour later I take the car out again and about 100m down the road the car just dies... I've gone WTF??? I turned it over and it started straight away. Feeling anxious I stop for a sec to check it out, it runs fine, revs fine and seems good so I continue on my way.

I get 5kms away from home and the car dies completely again, but this time it wont start when I turn it over! I take off a spark lead, put an allen key in the end and hold it to the strut tower while turning the engine over... I have zero spark!!! So I called some help and got towed home.
When we get home, the car starts fine and runs again!

Who can help?

I've been thinking DFI module... does this sound reasonable? Or are there better options.... could crank angle sensor be an option? Or would that just screw the timing up rather than kill the spark entirely?

[VSSECO]

PS No error codes were logged

[hako]

Crank angle sensor would be my first guess - may not always log a code. If you can change this yourself it would be your cheapest substitution. Good Luck.

[VSSECO]

Thanks Hako. I'll give that a try. Just out of curiosity... could a stuffed CAS give off a clicking noise on decelleration? Ive never had a close enough look at this sensor to know how it works.

[vr1962]

i reckon hako is right on the money. i had a similar prob and changed the cas and all good now

[hako]

It can give a clicking noise if the harmonic balancer is touching the CAS. Might be an idea to have a close look at the rubber part of the HB ....also watch it while the engine idles to see if there is any movement/wobble . If the rubber centre of the HB fails, the HB wobbles and the reluctor teeth on the other side of the HB touch the CAS.

[VSSECO]

Ahhh excellent, sounds like that'll be the go.

So, for my next question... IF I had a wobbley balancer that was constantly tapping on the CAS, do you think that would have been the cause of the CAS failing? I think I should check the condition of the HB before I ruin another CAS. It doesn't seem rough, what is the best way to determine whether the HB has shat itself???

[VSSECO]

Ok so I've taken the balancer off and retrieved the old CAS... its in a shit of a spot. The balancer seems fine, the rubber looks good to me... not sure if I should just throw a new one on while i've got it apart anyway... maybe 5% underdriven :-)

[hako]

The best way I'd imagine would be to put it back on the crankshaft and see if you can get any movement out of it - there should only be a tiny amount of flexing. Also look closely at the CAS and the reluctor teeth to see if there are any shiny "witness" marks - use a bright light.
Most times the HB will start to throw bits of rubber or crack on the face or start to wobble and/or touch the CAS. If it looks OK then just change the CAS as the HB is a bit more expensive.
If the car still has dramas then it's back to the drawing board.
Good Luck.