Thread: Lucas ignition amplifier replacement by Bosch 024

Update. I moved the dizzy > BIM024 wires as far away from the alternator as possible ( within the length of wire ) and it seems to have fixed the problem. Maybe my alternator is emitting loads of RFI and disrupting the ignition signal that is sent to the ECU? I might change the condensers at the back of the alternator and distributor as they are supposed to suppress any RFI. I don't' like the wires being out in the breeze and unsupported most of the way. I will check the air gap again too.

Thanks again bee utey.

Every 2 pulses from the ignition result in one injection event by the ECU. So it's likely that when the ECU sees extra pulses it goes a bit funny. I've not used shielded cable for that job before but I'm sure you could get some from Jaycar or similar. A strip of foil and tape could do it too, so long as the shield was earthed at one end.

This thread is the reason I joined.

My problem:

Coil - hot 12V when ignition is on
(Old amplifier bolted to dizzy)
Coil gives spark on ignition on (Turning over and regular sparking)
No spark from dizzy to wires/plugs - therefore no start.

This has been intermittent till I came home the other day and now its no go at all. I did drive up the curb, bumps make it come and go. Now its gone completely.

New LR cap and Rotor and gets spark from HT wire in regular beats. Also checked the bump button?? The one that goes off in a crash, pushed it down. Not sure how to check that.

I am guessing it might be something external to dizzy. Therefore just removed and cleaned all grounds and checked block to battery -.

Why no spark at plug? obviously something stupid I'm missing.

The tilt switch mainly cuts the fuel pump, not the ignition so shouldn't stop your spark.

If your rotor is new stock, I would suspect it was China manufactured and not fit for purpose. Try either another one or a second hand one out of a working vehicle. Cheaply made rotor buttons burn through really easily. Test the rotor button as per items 9 and 10 in the diagnostic post here.

Make sure the white/black stripe wire is secure at the coil negative post, this is the rotation signal to the ECU and no injection/fuel pump will take place without it.

Wires checked and double checked.

The car ran fine and idled better after replacing the rotor and cap (Original LR parts as I know about the cheap ones). This is definitely something else. the problem was definitely intermittent before and after cap and rotor change. (But I was changing them to find the intermittent ignition problem)

The car would drive fine then all of a sudden bog down, with fuel smell but no firing, then 4-5 seconds later, fire right back up.

Also: I changed the amplifier with a working one from my previous Disco that had the relocation kit - so I know it worked fine.

I have tried all the basics. The problem is now no ignition at all, but steady pulsing spark from HT lead when cranking over the engine, but no spark from dizzy to plugs. Strange!!

Strong smell of gasoline when stomping on throttle from exhaust pipe. So pretty sure thats fine. (Interesting that my fuel rail has no schraeder valve - I have two others in the garage that do - so will switch them next time its all off.)

Hi, just completed the change from coil-mount amplifier (two wire DLM8 distributor; petrol (no LPG, 1992 RRC) to the BIM024 option.

Previous symptom was consistent lack of starting when engine hot over a couple of months or so. Lots of farts and stumbling; then it would fire up. But, once running, no issues at all.

Then, latterly, trouble starting from cold with brief running then dying. Then, no start at all. Multiple testing revealed occasional (weak) spark from coil HT lead. Then no spark at all.

Removed Distributor to get at amplifier.

Removed LR amplifier from distributor; plumbed in the two new wires (per BU posts and photos - thank you!) to the BIM024 module; re-directed the WB and W wires accordingly.

Note: this setup is a 100? Special (Series body on RRC chassis), and so my coil mount is not any where near standard.
(read ? as quote marks in the text - thanks)


Contrary to the ?up to 1990? RRC wiring diagram (Haynes), there was a WU (white/blue) wire joined into the WB wire leading to the distributor amplifier connector, hidden within the loom. The WU wire lead back to the ECU. The ?post 1995? Haynes diagram shows the WU wire connected through Tune Resistor #1).
( I suspect the 1992 model was in that grey area for published wiring diagrams for models)
I left it in place.

Nothing else in/on the EFI system/wiring/connectors was altered or changed.

Re-install distributor to original position (timing position checked)

Pre-start tests showed all Volt and Ohm readings OK.
Main HT lead from coil left disconnected and within 6mm of Earth
Turn key to Start. Excellent spark to Earth.

Then first actual start:
Instant firing; Then directly the three step idle routine as expected from the System:
About 1500 rpm from start.
Then about 1000 rpm
Then about 700 rpm with steady idle
All in three, brief, distinct steps.

All seemed to good!

Then, within about 60 seconds, a jump/instant increase to 2000rpm for about 3~4 seconds.
This was then followed by a sudden drop to about 500rpm, with uneven firing, then a stop dead.

Multiple starts after checks and tests of the new wiring saw similar running problems.

The same problem has occurred after letting everything cool down.

Then, after a start, I found I could prevent a stall with judicious tweaking of the throttle pedal, just after the revs ?jumped? to 2000rpm.

This initially suggested an Idle Air Control Valve (Bypass Idle Valve/Idle Valve) problem ( just Google it).

Then, after much Googling, I found this helpful page.
To me, this explained exactly just what was going on as the system started.

With this in mind I went back to basics.
I hooked up my timing light and saw :

1. On start up and after a few seconds of idle, the timing light on the crank pulley showed 9deg BTDC (about normal, I think)
2. Then, after sometimes 30 seconds, at other times 10 seconds, suddenly all would go haywire; an increase of rpm (I am guessing about 2000) and irregular rpm.
From what I could see with the timing light, the timing had gone completely over-advanced.
3. As above, I could increase the throttle (manually) to prevent the stalling.
4. After some tweaks with the throttle, I could get the engine to settle at a steady idle.

Bear in mind that I have checked :
All vacuum hoses in/on/around the Plenum, Chamber are tight.
The Idle Air Control Valve (Bypass Idle Valve/Idle Valve) seems to operate OK
(seen to be moving in/out when removed but plugged in)

One issue not resolved:
There's no difference in timing (via the timing light on the pulley) when the Distributor vacuum hose is removed or connected, regardless of rpm.
But when the engine is running, increasing rpm shows a steady advancement of timing with no noticeable irregular firing.
Idle shows 9 deg BTDC; at about 3500rpm, light shows timing at the letter R on the ?BEFORE? stamped on the crank pulley.

Then, when the ?problem? (#2 above ) occurs, the timing light on the crank pulley shows a huge ignition ADVANCE.
Judicious tweaking on throttle( initially opening it on rpm dropping, then closing it, etc, etc) can prevent a stall. After such tweaks all seems to settle with the timing light showing 9 deg BTDC.

My Question:
Before the ignition amp failure ( I can only assume the original problem was such) , the engine ran smoothly over all rpm ranges.
I've checked all connections ? all tight. I even tried reversing the Distributor pickup to BIM024 module wires (#3 and #7). Reversed them from what I had originally (per postings), it was worse ? no running!). Hence swapped back.

Should I be chasing a Distributor internal mechanical problem?

Video of the problem as seen, here : [ame="https://youtu.be/fQvs8TjhhmA"]https://youtu.be/fQvs8TjhhmA[/ame]

Sounds like you're picking up interference in the wires from the distributor to the ignition module. Keep the wires well away from the main wiring loom and especially the alternator. Run some coaxial wire for the pickup if you can get hold of some, or wrap the insulated wires in foil and earth the foil at one end.

If all else fails, get another module. I had one last year that was faulty out of the box and had to be replaced. Not sure it did anything like yours though.