Some troubleshooting on ignition! Suggestions and methods!

[S13xCrazy]

Some things to trouble shoot on the D21 truck with Z24 engine...This all came about from me messing my truck up from going through a very large puddle at a decent amount of speed...I have spent the last few days trying to figure it out. Figured I would post my new knowledge!

DISCLAIMER: I hold no responsibility for anything you mess up! Be careful with ignition components, They are very high voltage and deadly!!!

Does your Tachometer not work? Well first thing is first, do your other gauges work? If not, you probably popped a fuse. Check that out. If only your tachometer is not working, chances are that either you have a cut wire, OR you have the same problem that i had. Next to the Intake Ignition coil (drivers side front of engine bay), there is a transistor pack. This pack plugs into the engine harness, and the ignition coil. Check to see if you have spark with the Ignition coil. If you don't, chances are that this pack went bad. This ignition module (Intake side) controls both the spark and the Tachometer, so if one doesn't work, chances are neither does the other!

The way I checked this module was by simply checking for resistance on each wire. On the old one some of them appeared to be pretty high (around 14), and the new one they were lower, around 7 or so.

My truck seems to be misfiring, what could be causing it? Although there are many reasons your truck is misfiring, I am going to touch on a few that I had to deal with.

Maybe a Tune-Up is in order? This could be a very simple problem. Just sit back and think to yourself, "When was the last time I did a tune up?" If your answer is "I can't remember" or "A long *** time ago", you might as well go ahead and start there by getting yourself a new distributor cap, distributor rotor, new spark plugs, and new spark plug wires. Why not start with one your asking? Well, all of them together only cost around ~60 or so bucks, so It never hurts anyways!

EVERYTHING FROM HERE ON OUT ASSUMES YOU HAVE DONE A TUNE UP!!!

Do we have spark? If you already have done that, go ahead and check for spark on any of the plugs. Do this by pulling out a plug wire, and using either an old plug or one the one that was in your truck and sticking it in the wire. Now, wrap the wire with a dry towel or something, and then put on a glove. Next, hold the spark plug near a metal surface (unpainted) and have a partner crank the truck over. If you see spark, GREAT!, if not...oh ****. (JUST KIDDING! READ ON!) Do this to both sides (Intake and Exhaust),

No spark anywhere? If you have spark on neither side...then you could very easily be looking at a bad distributor...or if you went through a big puddle like me, a lot of other problems. You can go ahead with the following tests, but if you have spark from both coils in the later tests, then chances are it is in fact the distributor.

Spark on one side, but not the other? If you don't have spark on one side or another, then we know something is not working correctly. somewhere.

If you have spark on at least one side, we should be relatively safe to say the distributor is doing okay, and we need to look at other items.

Now, before the distributor we have the coils. To test to see if the coils work, there is a easy procedure you can take.

Testing Ignition Coils Pull one coil wire from the distributor, and then go ahead and wrap part of the end up with a towel and then put a glove on. Grab hold of the coil wire and put it near a metal surface again (non painted), and have a partner crank the truck over. If you have spark, you are good. If you have no spark, or very little spark, then you have narrowed your problems down even more. Go ahead and check on the other side.

If you find one that one coil is not firing, we need to go ahead and troubleshoot that region now.

From here, we have eliminated alot of items, and are basically down to three major items.

1) The wiring...I don't know where to lead you on this one, not an auto-electrician! Sorry!2) The coil itself...3) The transistor/module for the ignition coil. You can test this by checking the ohms, refer to top for more information.

I will continue to modify this/make it better, however I started getting tired before I could finish.

[Desert Rat]

good stuff! Thanks for the contribution.

[nismopu]

I am curious how you surmised the dizzy is bad when both coils are firing? If the dizzy is bad then the coils wont fire at ALL, theres nothing telling them to fire if the dizzy is bad. Either that or you need to re-word that part. Good info so far. peace.