optronic system, condenser and coil.

H

heapy

Member
Hello, iv just purchased a tired looking tobacco leaf 1973 3500 with 22k miles from new !! which has been parked in a garden for the last 24 years !!
its on the road now all beit demanding copious ammounts of spanner work!

At some point somebody has fitted a lumenition optronic system but the fitting has been done by somebody at home.. i have just replaced all leads, dizzy etc but at high speed /revs the engine starts to die and comes back once it has slowed right down. it did this with the old leads and dizzy etc, mechanical pump is good and clean as a whistle, temp is good and constant. i have fitted a new coil too which is the correct ballast resist type but there seems to be, still fitted what looks like a condenser to the coil on the positive side with its body as the earth on to the car body using the same nut which holds the coil down. ( this was on the old ballast resisted coil so i re fitted it) should this still be on the coil for some part of the igniton system or should this have been consigned to the bin with the points etc?? did the condenser originally sit on the coil and not under the distributer when it was a points based system??
could this be whats killing the engine at high revs?
Many thanks keith.
 
Could the advance / retard mechanism in the distributer be seized?

I had a similar problem a few years ago, although my P6 still has points. The weights at the bottom of the distributer, which move out when the revs increase were all rusted and siezed. A second hand distributor sorted it.

Could the fuel filter be partially blocked?

Colin
 
mmm thought it was to much of an easy fix.
any suggestions on what could cause such a lack of power and then near breakdown only at higher speeds would be appreciated.
do optronic systems do this or are they all or nothing??
thanx all
 
Talago said:
Could the advance / retard mechanism in the distributer be seized?

I had a similar problem a few years ago, although my P6 still has points. The weights at the bottom of the distributer, which move out when the revs increase were all rusted and siezed. A second hand distributor sorted it.

Could the fuel filter be partially blocked?

Colin
Click to expand...

The fuel filter is clear plastic and although there is a little bit of dirt at the bottom its still fairly new looking, ill replace tho. as for the weights that could be a reason as its sat for 24 years without cover tho it dosent do it every time, its an intermitten fault which made me think more electrical??
 
ps how do i check the weights are moving? will twisting the cam back and forth to hear them in a free state be enough or will i have to dismantle? (haven't got the useless "reversal is the same as dismantle" haynes manual at hand lol)
 
Best way is using a timing light, after checking that the weights aren't seized in the advanced position without the engine running, set the timing at idle, then rev the engine to see if the timing advances, if it does then let the engine return to idle and check that the timing returns to where it started to prove the advance mechanism isn't sticking.
 
you can check the machinal advance with a normal timing light

as you can the vac advance.

is the coil 12v or 8v ?
i think most electronic covertions use 12volt coil
this could account for loosing power at high revs as theres not enough voltage.
 
i think its a low voltage one because i bought the same as the old one (a ballast resisted coil) , yeah its fine and full of power at normal about town driving but on a dual carrage way seems to lose power sometimes dying right back like electrical fault , weak or icing.
i will give lumention a call tomorrow to investigate this idea. Thanx :O)
 
I may be TOTALLY wrong here:-

The lumenition module is not getting fed via the ballast resistor is it? I'm sure one general symptom of the module being fed via the ballast is what you describe...

Anyone else agree/disagree with my thought?

Addendum: I started this before martin1973's post showed up, but didn't submit until after (watching TV!) But yes, Martin's got the same train of thought as me!
 
Hello Darth,

You are correct indeed, for the supply to the Lumenition power module comes straight from a 12 volt supply, typically at the fuse box.

The standard Lumenition system requires that the ballast resistor / coil primary resistance combination provide a combined resistance of not less than 3 ohms.

Keith,

Where did the previous owner fit the power module? Is it right in the engine bay?

Be sure to check that the distance between the end of the chopper blades and their closest point with the optical eye is no more or less than 1mm. To adjust the distance, turn the base plate adjustor accordingly.

Ron.
 
Hello Darth,

You are correct indeed, for the supply to the Lumenition power module comes straight from a 12 volt supply, typically at the fuse box.

The standard Lumenition system requires that the ballast resistor / coil primary resistance combination provide a combined resistance of not less than 3 ohms.

Wow, glad to hear that!

To clarify, my thinking is that the supply to heapy's lumenition module has been wired wrongly i.e. wired after the ballast (i.e. wired to the 9V (I believe it's 9v?) 'coil' side of the ballast) instead of before the ballast (i.e. wired to the fuse box/ignition-switched 12V side)
 
I had a similar problem to this when my fuel pump was hanging off the side of the engine, not enough fuel flow to maintain the high rpm / load. Is there any way to check the level in the fuel filter when it is misbehaving, not sure there is.
 
hello all, thanks for all the suggestions. i have used and checked all your theories.. i have not been on as the car is taking its toll on me! my back gave out before the problem did :O/ !!
anyway yes the module is located in the engine bay, slap bang in front of the coil, so much so that the ht lead is pushed sideways. (not causing it to come out tho) but i will move the module anyway as is annoying. It has its own external power supply coming from the dash.
i'll have a look at the blades and distance from the eye, not quite sure what you mean but im sure all will become apparant when i can lean in to look!! failing that a nissan is on the cards lol. cheers :O)
I replaced the petrol filter for a larger and brand new one plus replaced all petrol hoses for larger bore ones right up to the carbs as the original plastic ones had been replaced for rubber so alls good there. pump is good and now tightended properly to engine (wasn't hanging off but loose enough to leak oil, tho noticed this when i cleaned and checked diaphram and valves) !
After doing all this the first thing to happen on fire up was the first carb started pouring petrol out from the over flow the sudden rush of petrol probably shocked it??
dismantled carb and used that evil vapourous carb cleaner on everything and inlet valve and found the float was was sticking at half way point too !!
all back together and was running fine for a while albeit a bit to lean tho,, untill i put my foot down yesterday, then the power loss came back with erratic tick over.
Where it had been running before, i now think its most likely carburation than electrical, so i will now dismantle again but do both carbs this time (only did one as was doing it by torch light now the clocks have changed for some archaic reason!)
thanks for all the support !!
Cheers, Keith.
 
Hello Heapy,

The Lumenition power modules are extremely reliable provided they do not get too hot. Their maximum reliable operating temperature is 85 degrees C. The location of the module in your Rover would I expect be placing it at or possibly over that critical temperature, and it may well be part of the course.

When you relocate it, down low at the front in the best location. The modules are water resistant, and will actually work without fail even if submerged.

When you take a close look at the chopper and the optical eye, you will see that the blades of the chopper pass between between the photoelectric cells of the eye. The distance that you need to set is between the end of the blades and the black metal body of the eye. Using a feeler gauge set to 40 thou (1mm) will see it spot on.

It does indeed sound like a complete carburettor overhaul is the go too.

Ron.
 
Ah right , got you now :O) will move the box to a cool place and check the gap tomorrow. while im at it i'll incorporate a hidden immobiliser switch too. cheers.
as for the petrol yes, gallons and gallons its my every day driver and iv never seen the forecort so much !! i use only tescos 99 octane as the original requirements were, i read is 100 octane.
cheers.
 
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