Hello all, I need some help. Just bought a 1991 RS 6 cylinder. I have no spark
I have replaced the following
spark plugs
ignition coil
distributor cap
distributor rotor
i didn’t replace the plug wires or the ignition control module as they both looked real good. And I had a second ignition control module and I tested them both no changes

the car hasn’t driven since 09.

im running out of things to replace , any assistance would be very appreciated

 

There are two parts to an ignition system. The primary and secondary sides. The primary is the lower voltage part. This is what fires the coil. The secondary side starts in the coil. Step one would be "are you getting power to the coil" and "is the distributor giving you the pulse needed to fire the coil". The signal from the distributor is a negative pulse (square wave) Two wires going to a coil one wire will have power in it. The other wire supplies the ground. The ground side turning on and off is what causes the coil to fire. This will show up on a voltmeter as an average or lower voltage. If you use a test light you should see a very fast flicker. The ground pulse comes from the spark module but it is triggered by a pick-up inside of the distributor. The pickup tells the spark module that and how fast the motor is turning.

How did you test for spark? If the coil did not have spark why would you replace all those parts the come after the coil? Even before you check for spark at the plug you check it at the coil. The best way to do they without real equipment is to use a spark tester. You can get these are Harbor freight, They put them on sale for $1.99, they also sell them at just about any parts store. One of the main reasons you want his is because the spark needs to be above 4000 volts to fire a cylinder. If is very possible to see a spark that is not strong enough to fire a cylinder under compression. The testers have a built-in resistor so if it firers the tester it will fire the plug.

https://www.harborfreight.com/in-lin...ker-63590.html

 

Thank you for the response and the detailed information on how the ignition works. It is helpful and I just admit electrical diagnosis is not a strength of mine, im more of a mechanical guy so this is all new to me.
i tested spark by pulling a plug and grounding it against the motor and then cranked the car. And no spark. I have power to the ignition coil however I feel that is where it stops and it does not make it past the coil and into the distributor.

 

I have not had a lot of luck with talking people through electrical issues. But here goes, Disconnect the ground side of the coil. Hook a test light clamp to the positive side of the battery. Touch the tip of the test light to the ground side wire. Crank over the motor. Does your test light flicker?



If it does not flicker its either the module or the pickup, It could in theory be a ECM but it is very unlikely. It could also be a wiring issue. (primary issue)

If it does flicker, then the coil wire should fire. (secondary Issue)



Report back what you find. Once I know what you found I can try to direct you to what I would do.

 

Thank you again for responding. No test light flicker at all. I tested the connectors going into the coil. Hopefully that was the correct test

 

No flicker means no signal to the coil to fire it. How did you test the ignition control module? FYI Looks on electronic component means next to nothing. I have seen ICMs new out of the box be bad and I have seen them fail after 40 years and just about everywhere in between, In many cast, since they are sealed under a distributer cap their whole life and all look about the same,

Some Parts stores can test spark module, Call before you go and verify they can do your model. After that you need to test the pick up in the distributor,

Just to verify you do have power to the coil? Test light hooked to ground and it lights when you hook it to the positive side of the coil,
Just to verify with the Distributor cap off you can see the rotor cap spinning while you crank the car?

This is a little different from what I showed you, This way of testing assumes you have power to the coil. The way I told just tests the grounding system with no dependence or power. For a beginner his way is easier,

While you have the module out for testing you can check the pickup

 

Hello, here’s an update. The pickup was bad and I ended up replacing the distributor now I have spark to my cylinders! Today will be the day to see if she will start. Stay tuned and thank you for all your help!

 

Well no dice, spark to the cylinders but still not starting. I will turn my efforts toward diagnosing the fuel delivery systems. More to come

 

Fuel pressure is the first thing to check. If that is in spec then you will need a EFI noid light. Most car parts store carry them. You can also get them through amazon or Harbor freight. THey should cost under 5 bucks but I will admit I have not bought one in a while .

 

Got it, my fuel pressure garage just arrived today. I’ll be testing it tomorrow