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[IrishKenCJ7]

Trying to diagnose a starting issue and think it might be ignition module. It recently started cutting out while driving and now won't start. Starter is spinning and engine seems to start until I release the key then it dies.

Anyone in UK sell these.

Thanks again

[xr6jeeper]

Have a read of this before you go spending wonga
http://forums.off-road.com/jeep-short-wheelbase/220243-1986-cj-7-cuts-off.html

[j33pky]

Try Lighthouse jeep... They def have them.....01953 681237

[Bubba]

I have never known one fail

However if you go to a scrap yard and look for a ford with a v6 granada up to at least scorpio or capri its the very same module and plugs strait in it will run a 4.2 or a 360 strange but true

And yes I know they are getting thin on the ground but you never know

[Mike Pavelin]

Ballast resistor on ignition coil circuit?

[dieselj20]

 

[eastryjeep]

There are some manufacturers nowadays that could learn a trick or two from that old Motorola module, imho they are as bullet proof as the 258 engine they hang on!

[Mike Pavelin]

I had one fail on a YJ with the 258. Used to pack up when it got hot.

[IrishKenCJ7]

My problem started on an exceptionally hot day but that could be a 'red herring'

I had a look for a ballast resister and didnt find anything that looked remotely like one on my 78 CJ7.Maybe my 78 didnt have one. I have a module from another CJ7 which ill try and change over. I must make sure it has a good earth from what I read online.

My battery's flat now wtih all the attempted starts, must pop down to Halfords and get a jump pack as those Aldi jump packs are useless once you leave them on their side.

Just to confirm would he ballast resister be the rectangular white thing I see online. If it is then I dont have one. I see other items connected to the ignition coil like fuses and another circular item on the inside of fender.

Ken

[Dave The Sparky]

Your ballast resistor isnt externally mounted its actually a resistance wire that is within the wiring loom.
Its also bypassed when the starter motor is turning to give the coil full voltage, so i would suggest a voltmeter is the way forward to see if there is the correct voltage present on that wire when the ignition key is turned on and the starter is not turning or just try your spare module first if thats easier 

[IrishKenCJ7]

The starter is definitely turning , or at least the engine is turning so the starter must therefore be turning.
Ill wire up the new ignition module tomorrow and jump it. If Its still and issue I think it will be one for the garage as I may be out of my depth again.

K

[Dave The Sparky]

Thats not what i meant Ken

Your coil has two supplies to it.

No1:The normal supply which goes through a resistance wire and drops the 12Volts down a bit (to about 9Volts i think), this is used when the engine has started and is running and is a reduced voltage so the coil doesn't burn out.

No2:There is a supply which gives the coil a full 12Volts, but it only does this whilst you are cranking the engine.

If No 1 is faulty then the engine would fire but then die once you release the ignition key from the start/crank position, but i would still try the ignition module first though as its an easier fix, but that is assuming your spare one is ok of course

[IrishKenCJ7]

OK I understand now but I;ve noticed some CJ7 have a little white component so I must just have the wire version.  I've checked the chiltons manual and dont see a reference to the wire.  I've uploaded a shaky video from earlier today. Coil is upside down but if you spot what I should be looking for let me know.

K

[xr6jeeper]

I think thats just a suppressor, it stops interference on your stereo system, like this one
http://www.ebay.co.uk/itm/1955-1956-1957-CHEVY-COIL-CAPACITOR-RADIO-NOISE-SUPPRESSOR-/150818894801?pt=Vintage_Car_Truck_Parts_Accessories&hash=item231d81b3d1

[eastryjeep]

Yup, thats just a capacitor.
The external resistor is a white ceramic block with a threaded terminal at each end.
You can usually turn it over to see the coil of resistance wire potted into the block.
You also generally find the resistor block mounted on the side of the coil in its own holder which is part of the coil bracket, and yours doesnt look like the correct bracket to me.
As a word of warning they can get quite hot and will blister your paint if you screw it to the bulkhead or somewhere similar, and obviously the ceramic doesnt like to be crushed, twisted, splashed or subjected to vibration.
The alternative to the block is a resistor wire which runs between the bulkhead connector and the coil, if I remember correctly it is a brown wire of appreciably thicker gauge than all the rest in that part of the loom. It is often easy to spot a failure as the insulation is knackered in some way, burnt, blistered or even melted away in a bad case.
The operation of the system is similar to this:
Key in start position feeds power via big white slider switch (behind dash) to starter solenoid, ecu, alternator and coil (both 8 & 12 volt wires live), hopefully engine cranks and fires.
Release key to run position, 12v feed to solenoid and coil are cut leaving only 8v feed to coil (usually high performance type as 8 volt to standard coil may only produce weak spark, poor performance etc).
When my rig gave me grief I ditched the external resistor, replaced the feed to the coil for the run position with a resistance wire and installed a short jumper from the solenoid feed to the coil. All gives the same effect in the long run and I stopped breaking the ceramic bit every time I blasted through a puddle.
Hope this helps!
If not try checking the main slider switch and connectors behind the dash, the bulkhead connector and all wires for continuity too, that loom is not exactly new!
Good luck!

[IrishKenCJ7]

God Im slow, just got back to this s few weeks ago.
I swapped the ignition coil out of a jeep that was working and heh presto I;ve got it to run and stay running however...
I have to keep pumping the gas to keep her alive otherwise she will cut out.

So I am looking at sorting the timing out again (done 6 months ago), just ordered my own timing gun or should i go and clean the carb as i had that tuned also 6 months ago. It was sitting idle for 6 months.

Sorry that was a question, what should I do next do you think?

[eastryjeep]

My guess is that either the idle jet in the carb is blocked or you have a blocked fuel filter.
The only thing keeping the engine running is probably the accelerator pump connected to your foot!