Thread: Does this sound like an amplifier module problem?

G`day Taz ,

could well be but i`d try cleaning /crimping all you connections first

then i guess you could take a volt meter with you for next time it stops and you could try .....

+ battery - coil , ignition on , should be zero or there about volts , then crank and volts should increase ( bit hard solo , i know ) . Coarse remove the coil lead but not so it can bite .

Tells if the amps switching .

Also if you`ve disturbed it for any reason check the air gap in distributor .

Also a rotor arm could play up like this . Take the cap off when you have spark , hold the coil lead 3mm off rotor and crank , no spark is needed .

Also the coil lead its self could play up this way , specially if it is not secured as in free under its own weight .

Another thing that will happen with them that is hard to find if your not aware is the wires inside the distributor can and do break internally .

As they are held in the dissy body at there entry into the dissy but have to move with the vacuum advance and bottom plate they can fail .

Really need to remove the amp (and vac module maybe , depends how you do it ) use on ohm meter , there should be between 2k to 5k normally but when you move the plate and wires there may be none and this will be the problem .

Only extra thoughts and i seem to think there`s something else i can remember just now but amps usually act as you describe before they stop working .

The reason this is fresh in my mind is because our 94 wouldn`t start after a short run but all it needs is a new battery and a starter if it reoccurs .

Having all the electric things it seems to like more than 12.04 volts to start easily .

Our 85 with the 4.0 still uses the electric ignition that is standard to it and you ignition is much the same as what our 94 has .

Cheers

Thanks once again PLR,
I was really struggling with a logical diagnostic approach, but you've given me plenty to renew the battle with.
Cheers,
Taz.

Taz
It isnt a simple fuel tank issue???
Dirty pickup,or blocked venting,miss-matched EGR Vacc hoses ???
Andrew

Make sure the Amp/Module has Heat Disappating Paste between it and the heat sink and Dissy body, if it is not getting rid of heat it could play up like you described, Regards Frank.

Thanks Gents,

The stop once thing and then run fine has continued to occur over the last two days. I didnt have anyone with me at the time so I could'nt check for a pulsing voltage on the coil. On the last time it happened, I just shut the engine off and waited for 5mins. Started again and it ran fine for the rest of the day.

I threw some money at today, hoping to solve the problem or at least fast-track the fault finding. I generally try to identify the problem before wimping out and replacing stuff but it's got the better of me this time. I replaced the amp module, rotor and cap (all Lucas). I also tidied up the leads, which were criss-crossing each other, and gave all the earths and all connectors I could see a clean. So far so good, although I havent driven her far.

The new module has a different connector - kinda like a large injector plug. This is a million time better than the previous rubber boot type which was a bi$%h to get off. Interestingly, while the all the components came in Lucas packaging, the components themselves have no markings, unlike the ones I removed which had "Lucas" and "made in UK" imprinted on them.

Did you place Heat Dissipating Paste under the new amp, they get bloody hot and need to get rid of the heat, does it now work?? Regards Frank.

Thanks Frank,
Yes the new Lucas amplifier module came with a tube of what looks to be silicon grease, which I applied following your advice. So far so good. Done about 150kms without a problem. One more trip to work (130km) without problems and I will call it "fixed" ..and then give it back to the wife :-(
Cheers,
Taz.

Originally Posted by Taz

Thanks Frank,
Yes the new Lucas amplifier module came with a tube of what looks to be silicon grease, which I applied following your advice. So far so good. Done about 150kms without a problem. One more trip to work (130km) without problems and I will call it "fixed" ..and then give it back to the wife :-(
Cheers,
Taz.

I'm having a similar issue with my '93 RR and have had a suggestion that I should replace the module/amp with a kit that relocates it away from the Distributor to a cooler area under the bonnet, was this ever an option for you?