Ignition problems on 18RC

[Jimmy]

Serious problems: (I can be a bit of a noob so bear with me)

Sunday last week was a couple of minutes from home and car started misbehaving. Engine seemed to rapidly cut in and out while i was driving normally (under no strain - had not been thrashing or anything just started after i turned out of a side street). Watched the tacho drop to 0 and then back up again within a second over and over again as i managed to just get it home. putting my foot down a bit harder seemed to help a bit.

Next day had a look at the car and checked:
timing - fine
spark plugs - fine
points - fine
thought it might have been a fuelling problem because of the way it was cutting out on my way home so spent time adjusting the air fuel mix on the carby and managed to get the car idling and revving properly again. tried it again later when it was cold and still ok so i decided i would be able to go out that night but took the tool box incase.

car was fine on way out but broke down at 12:30 on my way home. car had repeated the same trick from night before on the freeway on way home riding very rough because of it. then on orrong road i heard what i thought was a loud pop (not sure if its relevant or not) but when i finally got caught at a set of lights the car coughed and spluttered and died. After some time wasted i checked the coil pack by earthing the lead on the block and noticed no spark when turning over... so i thought it was the coil pack.

got it home. have since replaced the coil pack and lead. no love - still no spark when lead is earthed on block. fuses are fine. battery is brand new and test perfect.

does that mean the problem has to be between the ignition and the coil pack or could it be something completely different and im way off?

HELLLLLP!

ps thanks to airfireman for all his help already!

[mike1980ra40]

Hi there,
loud pop is usually a carby backfire, which can be caused by the vacuum advance in the
dizzy not working. which will make the engine feel like its running on 3.

[Brad-KE35]

I can nearly bet my balls on this, that its the ballast resister the long white thing near the coil, mine was doing the exact same thing, when I turned a corner it would splutter but come good in a straight, turns out the wires were loose on the ballast resister. Might want to give them a once over. Let me know how ya go.

Cheers

Brad

[Jimmy]

replaced the ballast resistor as well as the coil pack and it tests fine so i don't think it can be that.

fairly sure the pop came from the driver side and also, if the coil lead isn't sparking when earthed wouldn't that mean this dizzy isn't getting power anyway?

keep ideas coming please. I'm still stuck

[GA61XX]

This diag' may help..
(was done for electronic conversion)
But may help you find the wires ..



you should have +ve 12v on the coil.. & -ve is switched.. this makes the spark..

cheers

[lexsmaz]

If the tacho drops to zero as you are driving along & then shoots up to the normal reading, it is an electrical problem, sounds like a broken or loose wire, or possibly the condensor is faulty, it will cause similar issues & usually worse when the engine heats up .. ( its mounted on the side of the dissy ) but also check all the wires around the coil & ballast resistor etc, also check the points wire inside the distributor, that its not loose or actually broken, & just touching at times ..
Also you talk about earthing the coil lead to the block, i pressume you had an air gap when checking for spark .. Also you talk about a coil pack ? is it a singular coil or a coil pack ?

[Peter Fanelli]

Well for what it's worth you might want to check the ignition fuse.
Believe it or not I used to have an RA-28 which used to crack, not burn out the ignition fuse.
Three times I got caught with a hairline crack in that link of that fuse.
It would start ok but as soon as the key was released it would stop, so I got pretty good at driving it short distances holding the key just enough into the start position to bypass the fuse and ballast resistor and get out of traffic.

May not be your problem but who knows.

[Jimmy]

Talking about ignition coil (singular) my bad. Yeah there was an air gap of a couple of mill. Using the multimeter, I can't get a 12V reading across the ballast resistor. Also, I couldn't get an earth reading from (what i think is a capacitor) that is attached to the side of the coil and earthed through to the car body. Fuses ok.

[o_man_ra23]

There is a .22 uF capacitor on the +tve side of your coil... guess what, thats what your condenser is too!! Just called a different thing, so a condenser will happily replace this. You won't get a direct earth from it, it will isolate you from earth at DC. Things to check are:
Points - condition and gap
Dizzy advance plate earth wire... it connects next to the points inside the dizzy, and then goes to the body of the dizzy.
Dizzy clamp - this earths the dizzy, so should be clean where the dizzy contacts the clamp.
Condenser
Black wire that goes from the dizzy to the coil -tve. This is also the feed to the tacho
Tacho (it is connected directly to the coil -tve, so is a remote possibility of the point of failure)
Feed to the ballast resistor - there are 2, one from the ignition switch on (resistor sits between this feed and the coil +tve) and one from the ignition switch start (bypasses resistor). Might want to disconnect the small wire on the starter to test voltages on this.
Coil - though you did check this.
Earth strap to the block
Coil lead
Fuses

Those are about the only points of failure you have to prevent you from getting spark to the coil lead. If all of them are fine, let us know.

[77GZE]

My mates TA22 did the same thing...dissconnected the tacho and it ran fine...maybe a faulty tacho.
Steve

[79GT]

i am the mate 77gze discusses above, i also had an issue with my tacho, except once mine was running it wouldnt die, it would just not start the next time, i would leave it for a couple of hours and then it would start first time. remove the wire running to the tacho off the coil. could either be the wiring or the tacho itself, (it was the tacho for me) worth a try mate.

if no love there, ask yourself this...does the car only stall at idle, or when you take your foot off the pedal. if this is the case, there is a small solenoid on the side of the carby that needs a 12volt feed that supplies fuel to the engine at idle, with out this, the car wont idle. or it could be a dodgy connection if it is an intermittant problem. could it explain the coughing and spluttering, being starved of fuel, but why it runs better when the revs are up - hence not rellying on the idler solenoid.

good luck mate, let me know.

[79GT]

Hey mate, how did ya go with your issue...any luck.

Jamie

[Jimmy]

cheers for the advice mate. havent yet had a chance to check it out. things are really intense for me at uni right now with exams very soon. will try to have a look some time this week at both of the things you suggested and see how i go.

thanks again.

james.

[79GT]

no worries mate. if ya get really stuck, let me know and me and steve might be able to give you a hand at finding out the issue if ya still cant get a grasp of it.

i know what you mean about uni, it is officially raping my time in the ass ten times sideways. havent touched my celica for the last week and a half .

good luck problem solving. Jamie

[Jimmy]

hahaha sounds like you're doing engineering as well.

i do mechanical engineering at curtin. i have 2 assignments due and 4!! exams in the next 14 days!