Ignition system problem.

ianobrien

I'm posting here as there may be more help here rather than the DIY forum. If its a problem, Mods can move.

Problem. Ignition system breaks down when the engine gets hot, usually after 4 to 5 miles. Starts as a small single high speed miss but gets worse and stops after half mile.

Changing the dizzy cap and rotor arm cures the problem and it runs away grand, both high speed and town running where engine temps rise. Idling the car for 4 to 5 minutes to heat things has no effects. It looks like the problem is fixed.

The problem reappears the next time the car is taken out and again solved by changing the rotor arm and dizzy cap. Car runs again like a train.

I think its not fuel vaporisation as I can leave it idle for 5 minutes with no problem and it runs strong after cap and arm change. Its probably not the coil as the car runs fine after dizzy cap and rotor arm change. (I can do it now in under a minute!). Fuel filter changed and plugs cleaned and gapped also.

Car, '77 Ford Escort, 1300 GT engine, with Aldon dizzy, Lumination ignition (so no points or condenser). Magnicor ignition leads, Bosch coil and Weber 32/36 DGV carb.

Any help appreciated as its getting expensive in dizzy caps and rotor arms. I usually only carry one spare set in the boot!

unfit2006

I would put a set of points and a condensor back in as a trial. See how she runs on them for a few days.

Justjens

I'd change everything if it was me, doesn't seem like it's cap and rotor arm, leads and coil are next. Does the coil get hot where it is, move it somewhere cooler or change it.

Basil Fawlty

Changing the cap and rotor is just a distraction. Start again.

http://en.wikipedia.org/wiki/Anchoring

If its breaking down when warm then it must be either the Lumenition set up or the coil.

As suggested fit a set of points and condenser to get it back to square 1 and start from there. Also check for a ballast resistor to the coil if fitted and check that too.

ianobrien

Coil stays cold, well it did the first time. I didn't check the second time as I burnt my hand off the heater return pipe. The weird thing is that it runs away fine after changing the cap. I've standard HT leads and I'll swap them but I don't think its them as the machine runs fine. If its the HT leads I'll be fairly cheesed as they are Magnicor competition leads.

Putting in points is going to be a last resort as I'll have to pull out the dizzy to swap and rewire. I've never heard of Lumination giving trouble. I hate points anyway so I wouldn't leave them in the car anyway. If I pulled the dizzy I'd install the Motorcraft with Aldon Ignitor fitted instead temporarily. The advance curves in the Motorcraft dizzy are not ideal.

gctest50

Sounds like the spark is getting weak - so when you change the cap and rotor it works because it has an easier time

Wrong coil for the electronic ignition maybe ? - overheating and breaking down

Does it still use a ballast resistor ? - breaking down when hot - saw this b4

Check the output of the electronic ignition when its running well and then when its running bad - stuff like dwell angle, power delivered

type85

5 or 6 quick questions here:

"Starts as a small single high speed miss but gets worse and stops after half mile."
Does it miss while cruising at a high rpm or while Accelerating full open throttle?

"Bosch coil" is this a bosch BLUE coil?

"car runs fine after dizzy cap and rotor arm change. (I can do it now in under a minute!)."
So you change them as fast as you can and the cars runs perfect again for? another few miles?

Have you tried JUST turning the engine off for the same few minutes it takes to change the cap and rotor(opening the bonnet also), and then running the car to see if the fault is immediately present?

Have you inspected the inside of the caps you've taken off for TRACKING? (a suttle carbon trail left behind along the surface by a spark jumping/shorting to ground)

What spark plug gaps are you running?

What tappet clearances?

i'll expand later on each one and their effects

TeaBagMania

When the motor stops have you pulled a spark plug, grounded it, and turned the motor over to verify there is no spark?

Do you have a spare ignition coil you can test with, might be an ignition coil saturation issue.

ianobrien

To answer the questions.

Miss starts on half open throttle (the engine oil wouldn't be hot enough for me to do full throttle so I can't say if it would occur under full throttle). It happens both under load (climbing a hill) and no real load (eg. crusing behind another car)

Coil colour I can't say for definite. I can't swear which colour. I don't have the car with me during the week to run out and check

The last time it ran for over 25 miles after cap and rotor arm change perfect. I brought it home and left it idle at the gate while I opened them with no problems.

Restarting the engine with no part swap doesn't cure the problem. I had left it up to 5 minutes before to check and it still wasn't working.

Caps are clean inside with no marks that I could see

Plugs are Champion N6YC, gapped to 25thou. Running any other heat range and they foul up.

Tappet clearance is as per cam manufacturer (I can't think of it off the top of my head). That being said, I haven't check that this year yet........

I think I have a spare coil at home (or I know where I can "borrow" various ones) so I'll get swapping.

I'll also have to break out the multimeter (rather than my usual tester of a parking bulb and length of wire) to check voltages across the coil the next time it happens.

That being said, I don't have the car here with me so I won't be able to check items until the weekend.

Blue850

I had a Triumph 2000 do something similar, was dying every 30 or 40 miles, changing the rotor arm would get it going for another while
I found an old stock genuine Lucas arm from the 1970s. which cured the problem
I read an article in Practical Classics magazine about how a lot of modern made spurious rotor arms are breaking down rapidly in use.

kyote00

I had similar problems (yes problems) over the years on various Fords (precrossflow, crossflow and pinto).

Assuming its timed properly, trusted coil etc... then I'd check

- check weber --- all jets for gumming, check accelerator pump and idle jet and floats are working

- Not sure if that weber has auto choke, but on Pinto the auto choke was a pig for sticking on.

- Check for vacuum leaks on the inlet manifold. Sometimes if the engine mounts are old, and you put the boot down (right boot) there is enough movement at the manifold to let air in --- air caused weak mixture and a stutter....

It could also be the coil dying when it gets hot (after a drive)

steveone

Is the cap working loose?tape it on see what gives. Duct cold air onto the dist. As an experiment then drive it hard. If it doesnt happen then u know the dizzy is a problem. Also mite it just be your fuel flashing off in the heat of the engine? My capri was a sod for that but since an elect pump went in its been great.

jetfiremuck

Check that you have the correct coil for the replacement electronic ign you installed. It may be coil specific or need a ballast resistor .

hi5

I know on the Pertronix ignition they recommend you bypass the resistor and upgrade to a stronger coil like a Blaster or a Flamethrower.
Those electronic ignitions are hungry for juice:)

welder

Had a similar problem with my mk1 RS2000 last year, though it would take half an hour or so before it stopped. Went back to points no change, eventually when stuck above Glencree ran a temp live from batt positive to the coil and she fired up straightaway. Reckon it must be a dodgey hazard light switch as the ign live goes through it, Bypassed the switch and has'nt happened since ! The temp wire is still wrapped round the battery post just in case !!

ianobrien

welder wrote: »

Had a similar problem with my mk1 RS2000 last year, though it would take half an hour or so before it stopped. Went back to points no change, eventually when stuck above Glencree ran a temp live from batt positive to the coil and she fired up straightaway. Reckon it must be a dodgey hazard light switch as the ign live goes through it, Bypassed the switch and has'nt happened since ! The temp wire is still wrapped round the battery post just in case !!

That's interesting as when I stop (usually in some gate) I put on the hazard lights.

ianobrien

No update as I wasn't at the car last weekend. I went to Donegal marshalling at the rally, at Knockalla & Atlantic Drive.

The Historic section wasn't that large. The ex-works HRS sounded sweet though and the SWB Quattro looked and sounded feckin' lovely

MercMad

ianobrien wrote: »

No update as I wasn't at the car last weekend. I went to Donegal marshalling at the rally, at Knockalla & Atlantic Drive.

The Historic section wasn't that large. The ex-works HRS sounded sweet though and the SWB Quattro looked and sounded feckin' lovely

.......man I would give anything to have been there for that !

One of my best memories was Knockalla in 1988 watching the Sierra Cosworths in anger !

Anyway..........I would also check your battery voltage and charge rate. I had a similar set of symptoms a few years back with a Mercedes 600 W100. It had been restored by Karl Middlehauve (Mark Expert) but now developed a misfire. Eventually I discovered that one of the alternators, they have 2, was overcharging to 18 Volts causing the none OEM electronic ignition to overheats and start misfiring.