No Spark - Distributor Pickup?

[Adrian351]

G'Day Guys,

Just when I was building ignition confidence again after my Bosch BIM024 ignition module and matching coil conversion....it drops dead today, as if the ignition had been cut. Engine cranks AOK but zero response.

It had been running excellent with the new module/coil for the last week and has performed really well in hot weather (where the Lucas one would die).

After testing today, I've got a huge spark from the spark lead from the coil (removed from centre dissy cap) when cranking the engine (easily jumps an inch)...just earthing out on the car, but there is no spark at the actual spark plug leads. It seems to have plenty of fuel...I can hear the pump prime and can smell it in the engine bay.

With cap removed, the dissy rotor spins OK when cranking.

I read about checking for resistance along the 2 distributor pickup signal wires (that attach to terminals 3 & 7 on the module), but I'm getting nothing. I pulled all the insulation off along the wires from the dissy pickup to the module and even at the 2 original wires from the dissy pickup, there is no resistance.

I have a brand new RTC5090 dissy pickup plate assembly that I haven't fitted yet, but it also shows no resistance across the pickup terminals. There was a small loose metal clip floating in the box (stuck to the magnet) which was pretty dodgy. Looks like the small spring steel clips that bend under the assembly to earth the top rotating part of the setup to its base....so I don't think it's fallen off, but just got dropped in along the assembly line. The shop said just fit it up and if it doesn't work, send it back.

But before I do that, are the pickup wires supposed to have resistance/continuity?

Also, I've got some brass feeler gauges to set the airgap on the pickup but can't find any info on setting the gap....every manual says "set at the factory - don't touch". So, is it the 2 post screws on the magnet next to the pickup that you loosen that allows you to adjust the gap, then re-tighten, or is it the 3 post screws that hold the plate to the dissy body that move for adjustment?

Or could I have killed my brand new BIM024 module? It's got 12v power OK.

Thanks in advance!

[Graeme]

Check the cap for cracks or carbon tracks and the rotor button too. Your big spark will jump anything slightly conductive.

If your spark plug leads are carbon then they may have burnt out. I had to run old style wire leads on my first RRC with its ignition conversion.

[Adrian351]

Check the cap for cracks or carbon tracks and the rotor button too. Your big spark will jump anything slightly conductive.

If your spark plug leads are carbon then they may have burnt out. I had to run old style wire leads on my first RRC with its ignition conversion.

Thanks for that.

I would never have thought my 6 month old rotor button would be at fault....but I found my old original Lucas rotor and swapped it over...boom, fired straight up!

The faulty rotor looks perfect.

[RRC James]

Thanks for that.

I would never have thought my 6 month old rotor button would be at fault....but I found my old original Lucas rotor and swapped it over...boom, fired straight up!

The faulty rotor looks perfect.

What brand is the faulty rotor button? Where did you buy it from?

[Adrian351]

What brand is the faulty rotor button? Where did you buy it from?

AllFourx4 fitted the new rotor several months ago, after the original ignition module failed. They commented after installing the new module that there was a weak spark at the plugs and the dissy rotor was the issue. Noting, I had just bought and installed a new dissy rotor from them several months prior, so I was a little puzzled....but in hindsight, I'd bet 10 bucks that the old (new) rotor was also starting to show signs of arcing, but I don't have it.

I bought a cheap replacement brand they offered and they installed another new cheap item (not original)....see pics with the square edged electrode.

I bought a 3rd dissy rotor from them last week (non original unit), but the design was totally different from the previous 2. However, I never installed this, as some other people had said to reuse my original Lucas rotor, which I did with great success.

A few people mentioned that the cheapo dissy rotors with rectangle edges on the brass electrode can cause the arriving spark from the coil to arc all over the place inside the dissy. Whilst I didn't notice this on original inspection, after taking some photos of the rectangle edged rotor, I can see a ton of evidence of this happening. The plastic edges on top of the rotor where the carbon contact touches the rotor has all turned grey as if it's been constantly zapped, as seen in the pics.

I've also included a photo of the latest rotor I bought which is listed as an "AllMakes4v4" brand and it has nice rounded edges like the original Lucas OEM rotor. However, this one would have needed a ton of force to push onto the dissy shaft so I opted not to use it.

Moral of the story, don't skimp on dissy rotors, never use the rectangle ones and opt for an OEM one.

158318158319158320

[350RRC]

The HV side of ignition has some funny problems.

I used to go through Bosch distributer caps about every 20,000 kms because they would crack and arc through the cracks causing misfires on lpg.

Bad misfires when starting............... think shattered snout on a 350 starter, couple of teeth missing off the flywheel, muffler opened like a sardine can, etc.

Then Bosch induction leads get fitted........... same dissy cap for way over 100 thou, no backfiring starting on lpg at all, etc, etc.

The grey arcing on your rotor arm around the centre contact from the coil suggests to me that maybe the plastic is a bit conductive and leaking to earth through the dissy drive shaft

cheers, DL