123 dizzy

[stiky]

Hi i have a 3.4 s type fitted with the 123 electronic ignition i have a misfire on 2 cylinders i have tried all routes to no avail however on taking the distributor apart the PCB has corrosion on some parts of it i did have a hose failure just before this problem arose from the rear of the water pump so water must have got into the dist/ does anyone know where i can send the unit for testing and repair.

cheers jim

[piman]

Hello Jim,

as I avoid electronics where possible I've no real experience of 123 distributors but was under the impression that it only carried out the spark creation and not distribution? I think that it still uses the conventional rotor arm distributor cap set up so any individual misfire should be downstream of the electronic part of the distributor?
Can you contact the supplier of the unit to get some advice?

Alec

[stiky]

Alec you are so right 123 does only send the signal to fire and the problem is beyond that i have tested the coil all seems ok on the ohms test compressions are not great however they are all within 5 psi of each other so no reason for 2 to misfire i have a new cap fitted and changed the ht leads plugs are new ngk wots going on ?.

cheers jim

[oldtimer]

Um, are, well,

The coil is making sparks, so that's OK, it ain't smart enough to provide 4 then miss two on a regular basis.

You say that a new dizzy cap has been fitted, double check for tracking.

You did not mention the rotor arm, after market items are notorious for problems

Are the cylinders that misfire next to each other?! ?

Do you know which cylinders are misfiring?

5psi compression variation across 6 cylinders is good, what were the cylinder pressures recorded?

Just a few thoughts - hope it helps

Oldtimer

[stiky]

Hi your right about the rotor arm i did not like it so i fitted the original the compressions are all at 125 and 130 i have one low at 122 but it is firing fine the cylinders that are missing are 3 and 5 next to each other on the dizzy ? a bit suspect i believe may buy another cap and rotor arm.
cheers jim

Um, are, well,

The coil is making sparks, so that's OK, it ain't smart enough to provide 4 then miss two on a regular basis.

You say that a new dizzy cap has been fitted, double check for tracking.

You did not mention the rotor arm, after market items are notorious for problems

Are the cylinders that misfire next to each other?! ?

Do you know which cylinders are misfiring?

5psi compression variation across 6 cylinders is good, what were the cylinder pressures recorded?

Just a few thoughts - hope it helps

Oldtimer

[oldtimer]

I am pleased that the misfire is not on cylinders 3/4, that spells trouble --think about it!

I would suggest you enquire as to what correct/ ideal compression figures should be. Also the methodology used to achieve the results.

Don't want to teach Granny to suck eggs and all that

Oldtimer

[stiky]

I am pleased that the misfire is not on cylinders 3/4, that spells trouble --think about it!

I would suggest you enquire as to what correct/ ideal compression figures should be. Also the methodology used to achieve the results.

Don't want to teach Granny to suck eggs and all that

Oldtimer

The correct pressure according to the manual for an 8 to 1 is 155 psi but as i mentioned earlier the lowest at 122 is firing fine pressure attained with a gauge giving each cylinder 3 revolutions to get the max pressure they may be low i am not sure a new dizzy cap and rotor on the way clutching at straws at the moment.
cheers jim

[ecosselynx]

Hi

The fact that the two cylinders are next to one another in the cap, can I suggest you try changing over plugs, leads from other cylinders, if that doesn't move the fault, try other cap and rotor arm, change them one at a time. Just wonder if the gap to these two pick-up's is a bit different?

[stiky]

Hi John put a new cap and rotor arm this morning instant success all 6 firing perfect until it reached running temp/ turned it off for 5 min's restarted and 3 and 5 are back misfiring it,s not the leads it,s not the coil or compressions i am thinking that the 123 p c board is breaking down under heat i am clutching at straws again but i think that if i have it checked out it may be a step forward one way or another .
cheers jimquote="ecosse lynx"]Hi

The fact that the two cylinders are next to one another in the cap, can I suggest you try changing over plugs, leads from other cylinders, if that doesn't move the fault, try other cap and rotor arm, change them one at a time. Just wonder if the gap to these two pick-up's is a bit different?[/quote]

[ecosselynx]

Hi Jim

If you recheck from cold and have the same happen once its warmed up I'd have to agree with you. Have you been in touch with the people you bought the distributor from or 123 themselves!

[oldtimer]

Hi Sticky,
The fact that the engine ran on all six pots seems to eliminate the internals of the engine.

At least you can concentrate on the ignition side of things

Oldtimer

[piman]

Hello Jim,

was it running without misfiring on the old distributor, if so i suggest refitting it to see if it runs on all six again, which would indicate the electrickery is the problem or not?

Alec

[stiky]

Hello Jim,

was it running without misfiring on the old distributor, if so i suggest refitting it to see if it runs on all six again, which would indicate the electrickery is the problem or not?

Alec

Hi i sent my 123 dizzy to a company called Albertronics in the Nederlands a chap called Frank a first class service in all aspects tested and replaced all the electronics and back within a week i have not fitted it yet the next few day's will tell if it was the dizzy or not.

[epbanks]

Hi Stiky,

I realise this post is now 4 years old but I am wondering if your problem was a result of a faulty 123 Dizzy?

I am having exactly the same issue in my Series 1 XJ6 and suspect the problem may well be the 123 Dizzy installed.

Very much appreciate any information you can provide.

Cheers,

Ed