Ignition problem

How-to's and repair secrets for your 4WD can be found here. Have a question? Ask it in here!
Post Reply
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Ignition problem

Post by kitchman »

I have been posting regarding the OEM carburetor flooding problem and have discovered some thing new. The engine attempts to start only when the ignition key is released and returns to the run position. Having run out of weather and sun light I couldn't confirm my suspicion that for some unknown reason (possibly a fault in the ignition switch} there is no spark while the key is switched to cranking. If this is true it probably is the cause for the start up flooding problem. Anyone had this problem?
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Ignition problem

Post by Petros »

never seen that, but anything is possible. ignition switch on steering column could be worn out, but I would double check everything else before I assumed that was the problem.

A bad starter could cause it to pull down the voltage so much it will not spark, usually it will crank very labored. i have seen that. Can you roll start it? put a voltage meter on the battery and see what happens when it is cranked. try a separate jump wire directly to the distributor to see if that makes any difference.

good luck
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Re: Ignition problem

Post by kitchman »

Thanks for the reply!
Problem update: The starter is very good, no problems there. I recall having a similar problem with another car years ago, but can't remember what the solution was unfortunately. This said I asked a friend who is an excellent auto mechanic and works for a dealership. I presented the problem of the Tercel not starting while cranking, but trying to start when the ignition key was backed off. He immediately identified with the problem, stating it was not an uncommon problem on some older cars. I don't recall which ones but it was definitely a problem where in the crank phase the ignition system would not be getting power to create spark. Now being some what convinced that my original carburetor flooding problem was being caused by a faltering ignition and not the carb, I set out to confirm this suspicion. Yesterday with the assistance of a friend I put an inline spark detector on one of the spark plugs and directed the friend to crank the engine. To my surprise, spark was observed and the engine immediately started. Back to square one? No, as I recall the issue of the engine failing to start and observing the subsequent carb. flooding was not a constant issue but rather intermittent. I still strongly believe the problem when it does occur is because, for what ever reason yet to be found, the system fails to get power in the start position. I was planning on removing the trim around the ignition switch a do the FSM continuity test on the switch, but if this is an intermittent problem there is no guarantee the test will be conclusive. Still looking for suggestions.
User avatar
Mark
Highest Ranking Member
Posts: 883
Joined: Mon Apr 22, 2013 9:49 pm
My tercel:: 1984 Automatic, 1981 sedan
Location: Victoria, B.C.

Re: Ignition problem

Post by Mark »

I think it's the ignition switch in the steering column. Looking at the wiring diagram, in the start position, both the starter circuit and the ignition circuit should be getting power, when you release the key to the ignition position, only the ignition circuit is getting power. It sounds like in the start position, yours may not be reliably contacting the ignition part of the switch as well.
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Ignition problem

Post by Petros »

if you have spark the problem is likely somewhere else. check the timing, try using starter spray down the carb, indicates lack of fuel.

A bad vac leak makes it hard to start, might also check all the vac lines.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Re: Ignition problem

Post by kitchman »

Thanks for the replies. My theory is that I have spark some times but have not been able as yet to confirm it. I am leaning toward what Mark thinks but if it is malfunctioning only some of the times the only two options are to take a chance and replace the switch or set up a bypass circuit that can be used to supply current to the necessary terminal on the switch's junction connector when it happens again and if it starts using over ride bypass then it would be conclusive that the switch is faulty.
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Re: Ignition problem

Post by kitchman »

Ok, this is my plan: I have traced the black trigger wire from the starter to a white junction connector near the battery. If and when the engine does not immediately start, I will place the key in the run position and proceed to unplug the white connector and place a jump wire on the starter side of the connector and connect the wire directly to the battery. If the engine starts in doing this it confirms a faulty ignition switch.
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Re: Ignition problem

Post by kitchman »

Problem update:
As stated previously, I waited for the next time the engine would not start, placed the key in the run position and while under the hood put a jumper wire to the triggering wire of the starter. Before attempting to crank I also placed a spark detector lamp on #1 cyl. and also placed a test light on the black and yellow wire that powers the dissy. and confirmed it was receiving voltage. When I jumped the starter the engine did not start and no spark was observed from the inline spark detector. This test ruled out my theory of the ignition switch being faulty and not supply voltage in the cranking position. The problem seems to occur most often when it is raining and damp. This intermittent problem has to be some thing going wrong in the dissy.since it was receiving voltage when ever the engine failed to start and no spark is observed. So it appears the problem was never the fault of the carburetor flooding, but rather the ignition failing and subsequently causing a flooded state because the fuel was not igniting and building up.
Will be going inside of the dissy. next
User avatar
rer233
Highest Ranking Member
Posts: 1013
Joined: Sat Jan 01, 2011 1:49 pm
My tercel:: Multiple

Re: Ignition problem

Post by rer233 »

Had similar symptoms years ago with my '83 SR5- turned out to be the ignition coil (inside the distributor.) Replaced it with a known good one, and it's been fine ever since. Good Luck!
if it aint there, there's a good chance it won't break!
83 SR5 Silver/Blue (Snowmobile/work beater)-totaled but drivable
85 SR5 Blue
88 SR5 White (the 'good' one)-not anymore-totaled
87 fwd silver wagon a/t
87 4wd dx Cream (a/t- not anymore- now m/t)
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Ignition problem

Post by Petros »

if it has trouble starting when damp, the problem is almost always in the distributor. I have had this problem several times, works perfectly when warm and dry, lots of trouble when cold and damp, or just damp. A cracked outer casing in the coil is common, takes in moisture and shorts it out. ONce you crank it long enough the votage heats it up and drives out the moister and it will start. Could also be a shorting out coil that becomes sensitive to moisture. Either way, when it is hard to start the carb will keep delivering fuel, and make it appear to flood, when actually the correct amount of fuel, it is not not getting burned.

Usually replacing the coil solves the problem. could also be a marginal ignition as well. both are fairly easy tests, see the servcie manual, it tells you what contacts to put a volt-olm meter to check for correct resistance.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Re: Ignition problem

Post by kitchman »

Problem update:
In the process of removing the dissy. cap I observed a white powdery residue on the dissy. aluminum casting where the forward most mounting bolt and condenser mount. Further examination revealed a hair line crack on this location of the dissy. cap. My first thought was that I had found the problem, but wanting to be certain the proscribed fsm test were performed. With a meter it was observed that the primary coil resistance was 1.5-1.6 oms. where it should be 1.2-1.5. Next the secondary coil resistance revealed no reading at all. The test for the ignitor revealed 11.9 volts. Today ordered a coil, cap and rotor which appeared some what pitted. The discoloration on the aluminum housing near the cap crack was probably due to arcing through this cap breach. Thanks for the replies!
T.B.C.
kitchman
Top Notch Member
Posts: 173
Joined: Mon Jun 20, 2011 12:24 pm
My tercel:: 1983 2wd tercel hatch back ,1986 SR5

Re: Ignition problem

Post by kitchman »

Problem update:
Installed new coil, rotor and cap the other day. The small gasket that the coil sits on was broken/cracked in two areas and applied some pematex gasket seal to fill the small voids in the two cracks. Well, so far it starts right up even after a rain. Going to monitor it this week to make absolutely sure. Any one have a handle on where to get that coil gasket that was repaired?
Post Reply