Perplexing No Spark

[Blue_Thunder]

Finished swapping my Holley Stealth Ram intake in (along with new small cap HEI dizzy and external coil) and have no spark. Have power going to the ignition coil with key on. Have power at distributor with key on. I have tried 3 different coils. Tested the Ignition Control Module and its good. I'm at a loss of what could be the issue is.

[NullHead]

Does the new distributor come with a new pickup coil? You're 100% sure the ICM is good? You should be able to ohm check the pickup coil that lives inside the distributor

[Blue_Thunder]

Does the new distributor come with a new pickup coil? You're 100% sure the ICM is good? You should be able to ohm check the pickup coil that lives inside the distributor

Brand new Petronix Flamethrower dizzy. Tested the ICM and it passed, and even swapped it out with another new one to make sure. Still no spark. Ive ohmed out the pickup coil and it was around 900 ohms, and turning the crank showed the resistance changing. Not sure what the spec is supposed to be. Really its the only thing left in the ignition system that would keep the coil from firing its secondary windings.

I have to venture a guess that the pickup coil is junk, even though its brand new, everything else was tested and/or replaced with another new part to verify.

Edit: Tested the pickup coil. Resistance between the 2 wires is 894 ohms which is in spec according to what I found (500-1500 ohms) and tested resistance bwteen pickup coil and dizzy body itself which should be infinite (and it is). I have no clue as to whats going on now as to why the ignition coil isn't firing.

[NullHead]

Is the primary side of the coil grounding? If I recall, the coil grounds through the ICM, which is where you get your dwell and spark pulses from. The pickup coil is the trigger which commands the ICM to ground the coil. I could be wrong, but I'd check into the ground on the ICM and make sure the coil is grounding.

After that, are you checking spark at the coil it's self? If there is spark on the secondary side of the coil, then the issue is inside the distributor.

[Blue_Thunder]

Is the primary side of the coil grounding? If I recall, the coil grounds through the ICM, which is where you get your dwell and spark pulses from. The pickup coil is the trigger which commands the ICM to ground the coil. I could be wrong, but I'd check into the ground on the ICM and make sure the coil is grounding.

After that, are you checking spark at the coil it's self? If there is spark on the secondary side of the coil, then the issue is inside the distributor.

Okay, so check the ICM ground, an ohm test should work I assume. And I am checking for spark at the coil itself using an in-line spark tester between the coil and distributor. I even checked the spark tester on my daily driver to make sure its working. I also, at risk of frying my volt meter I hooked that up to the secondary side of the coil while cranking. All I got was battery voltage.

Edit: Looking at the wiring diagram I am not sure where the ground is for the ICM, the wires go straight to the ECM...

Edit 2 : Just rechecking the pick up coil. Checked AC voltage output while cranking. Was .364 with slight fluctuation, never reaching .5 volts though.

[NullHead]

Sorry, I was a bit vague with my suggestion. Here is the wiring diagram:



What I was trying to say is put a test light with the light's clamp on the positive battery cable, unplug the coil's primary wiring and touch the tip of the light to the black wire(?) I'm not 100% sure on the wiring color, but if I recall one wire is black, one is white. Crank the engine and the light should flash. If the test light does not flash while cranking, the ICM isn't grounding the coil. There are two grounds the ICM needs, one on the bottom of the ICM that grounds to the distributor, another that grounds to the ECM.

This diagram shows you the ground to the ICM is through the ECM.



Perhaps I'm over complicating things, but if the ICM doesn't ground the ignition coil, the pickup coil in the distributor doesn't create a pulsing signal sent to the ICM, you will not have spark. You said key on you get battery positive voltage at the ignition coil, so that being said there really shouldn't be that many other things it can me. Hopefully this can help you further diagnose your issue

[Blue_Thunder]

Okay, so I did remove the ECM to put in a new chip, perhaps something got jostled and its not grounding. The distributor itself is grounding. I honestly can't see it not grounding to an aluminum intake. And I have a ground strap wire going from the firewall to an intake manifold bolt close to the distributor. Anyway just for clarity sake Ive converted my ignition wiring over to a small cap external coil setup (needed for the stealth ram intake).
So my wiring now looks somewhat like this
http://austinthirdgen.org/mkportal/m...ine_wiring.gif

2 wires come from the engine harness- Hot wire from ignition (pink wire) and tack reference wire to tack gauge (white wire)
2 wires go from the coil to the ignition control module- hot wire(pink with black stripe) and a white wire.
4 wire connector adapter plugs in from distributor to engine harness (that goes to ECM)

Other than the ecm itself not grounding I can think perhaps one of the wiring harness conversion connectors to the ecm is causing the issue?

[NullHead]

I mean that doesn't change too much. You should still have ground from the ECM at the ICM, coil's ground should still be getting a switched ground on the primary side. I wonder if the adapter harness is pinned differently?

[Blue_Thunder]

Okay, so looks like the ground is the pulse reference, purple with white stripe. I will check that and go from there, thanks for pointing me in the right direction.

At this point what I see is:
Reference wire has a open somewhere in it
ECM itself has crapped out an internal ground
Possible ground issue with the harness grounds itself on the intake manifold.

[Blue_Thunder]

I mean that doesn't change too much. You should still have ground from the ECM at the ICM, coil's ground should still be getting a switched ground on the primary side. I wonder if the adapter harness is pinned differently?

The colors for the adpator harness don't match up color wise to the cars wiring harness 4 pin connector at the ICM plug. Colors match at the 4 pin plug though. Not sure what to make of that. I just emailed IFI Connections to see if that may be an issue.

Also, my dvom meter went of the fritz so I made a test light with a small light bulb. Back probing the 4 pin connector going to the ECM from the ICM I got nothing, on any of the pins while engine was cranking. Not sure what to make of this now.

[NullHead]

Hold on, let's take a step back. Does your car have VATS? I wonder if this didn't turn into a vats issue and you didn't know it

[Blue_Thunder]

Hold on, let's take a step back. Does your car have VATS? I wonder if this didn't turn into a vats issue and you didn't know it

No it does not have VATS. I did however get a chip tunes based off on an 89 TPI setup. I already contacted the guy in TGO about VATS. It was disabled in the burned chip. Also, I though VATS doesn't disable spark.

[NullHead]

I don't know what it does honestly lol. Can't remember if its fuel disable or spark. Just thinking out loud

[Blue_Thunder]

I hear yah about thinking out loud. I have never been this stumped before.

[DanDalessandro]

VATS cuts fuel I believe. It might disable spark.
It has to be a ground issue. My cousin had a similar problem and it ended up being the battery negative cable wasn't grounded [emoji38] Simple things.

Edit: Nope. The VATS anti-theft system disables the starter& the fuel system on starting ONLY. On the coil is a plug from main harness ,two wires,pink and white. The pink is the 12v power feed from ignition switch. Does this wire show power with the key in the "run" position? You might also have a pickup coil inside distributor that is the culprit. Checking that pink wire is the easiest test to do.
Google power. Also found this: Yeah, those VATS systems are all too often tampered with and screwed up. take off your drivers side kick panel and have a look at the enabler relay that sits just behind the kick panel. That is where most people bypass the system. There are 4 wires going into the relay if I remember correctly and alot of people will bypass the relay and splice the two green wires together....i think they are green, but you'll know as soon as you look at it if something is wrong.