Mechanics

92 WEAK SPARK

1992 Toyota Corolla

Island Beauty,

My repair question was deleted so I am submitting it again. Thanks you for your advise.

1.6L, 4AF, 92 Corolla, 198,000 miles. Car died, cranks and will not restart. Compression, fuel and spark present. Spark looked weak; it is thin and yellow. You said do the following:

Check the the pick-up gap in the distributor and its resistances at G1-G- 185-265 ohms Ne-G- 185-265ohms

Coil and pick-up checks out-its in between the ignitor and the computer

Note: If computer don't see Ne and G signals it will not sent an Igt signal to the ignitor telling it to fire the coil and also it kills the injection system.

I don't know how to check the resistance above. Can you show me how? I attached a drawing I found from Autozone. Thanks again.

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http://www.2carpros.com/forum/automotive_pictures/73238_cOROLLA_iGNITION_cIRCUIT_DRAWING_1.jpg

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Ed51
June 8, 2007.




Check the coil's primary and secondary resistances-out of specs replace it or substitution to confirm.

Tiny
Rasmataz
Jun 9, 2007.
Check the coil's primary and secondary resistances-out of specs replace it or substitution to confirm.[/Quote: bba0047a35]

The coil primary and secondary resistance are both within specs. How do I check the magnetic pick up resistance? I could not find the terminals to check the resistance based on the drawing? While closely looking all the way down to the bottom of the distributor shaft to see if I can probe the magnetic pick up, I noticed that the bottom coil winding was exposed when the contact point was delaminated. I think this made the gear-like contact point on the shaft to lose the air gap losing the signal to the igniter. I will try to glue the contact back in place and see what happens. What do you think? Thank you for your advise.

Tiny
Ed51
Jun 9, 2007.
To rule out the weak spark problem, I replaced the distributor assembly with a used one from the junkyard. Good spark but still won't fire. This problem is just exhausting. Any more ideas? Your advice is greatly appreciated.
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Tiny
Ed51
Jun 19, 2007.
Could be a jumped T-Belt

You need to check the valve and ignition timing-

Tiny
Rasmataz
Jun 21, 2007.
The cause of the no start problem with the engine cranking is simply the timing belt. I think it is the original belt that it looked very, very old with just small cracks on the outside. Excellent part after 198K miles on it.. Usually the belt is broken in half or so in order to say that it is the problem. If I removed completely in the first place and made a thorough inspection I could have found the problem. Always check the entire old timing belt to see the underside especially the teeth. If its condition is questionable might as well replace it. Three teeth have broken off the belt while the car was running on the freeway causing it to go out of timing and die instantly. My advice is always pay attention to details before you go any further. Stick with the basic troubleshooting first. I did learn a lot from the many weeks of challenging troubleshooting though. Thanks for the advice of 2Carpros. Com that took their time to try to help me when my knowledge was exhausted. More power to you. See you next time.

Tiny
Ed51
Jul 3, 2007.

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