No start after engine install. Need Help!!!

Scott06 said:

The TB troubleshooting guide starts with verifying the tach wire isn’t shorted to ground …

Click to expand...

Agree, but that isn't what was said or tested, it actually "started"

alldodge said:

What???
The motor "Starts" with the Tach wire???

Click to expand...

I worded that bad. The troubleshooting starts with the tach wire. The engine does not start.

Scott06 said:

Disconnect the tach wire (grey) at negative post on the coil. This will remove any chance the tach is killing the spark

you can also disconnect it and check for continuity to ground with a volt meter.

woukd agree battery and connections both positive and negative are suspect given the voltage drop

Click to expand...

I disconnected the tach wire on coil with no luck. So now there is nothing on that post. When the troubleshooting guide starts with testing the tach wire you would think they would say to disconnect it and if it starts there's your problem. Why they don't mention that I have no idea. The only grounds I touched were the ones on the studs on the back of the motor and distributor module which are clean and tight. And I used an electrical connection/ corrosion gel on them (Dioxit) Any idea which ground directly relates to the coil not firing? I also have the battery on a charger and will check it again tomorrow but really don't think that's it. Thanks

jonny rotten said:

I disconnected the tach wire on coil with no luck. So now there is nothing on that post. When the troubleshooting guide starts with testing the tach wire you would think they would say to disconnect it and if it starts there's your problem. Why they don't mention that I have no idea. The only grounds I touched were the ones on the studs on the back of the motor and distributor module which are clean and tight. And I used an electrical connection/ corrosion gel on them (Dioxit) Any idea which ground directly relates to the coil not firing? I also have the battery on a charger and will check it again tomorrow but really don't think that's it. Thanks

Click to expand...

Go through the rest of the TB troubleshooting guide.

jonny rotten said:

So now there is nothing on that post.

Click to expand...

It would appear that you found your problem. Nothing is connected to the neg coil?

nola mike said:

It would appear that you found your problem. Nothing is connected to the neg coil?

Click to expand...

Good point . I have. 2 grey wires on mine one to coil one to tach. If no wire is on net post of coil It will not fire.

can disconnect the tach wire on back of tach Or check for continuity to ground with a volt meter

Sounds like you're really close — and kudos for tackling it all solo. Since you’re not getting spark and already have voltage at the coil, I’d double-check what's on the negative post of the coil. If nothing’s grounded there, it won’t fire. A missing or disconnected grey wire (tach) or a bad ground at the module could be the issue.

Also smart to put the battery on a charger — low voltage during cranking can definitely cause no-spark conditions with Thunderbolt ignition. Try measuring voltage at the coil while cranking (not just with key on) — should stay close to 12V.

Last thing — if you haven't already, walk through the Thunderbolt ignition troubleshooting guide in the stickies. Super helpful.

Let us know what you find — you're not far off.

jonny rotten said:

I disconnected the tach wire on coil with no luck. So now there is nothing on that post.

Click to expand...

There should be two grey wires connected to the (-) side of the coil

One for the tachometer signal and one for the module

The one for the module provides the "pulse" to let the coil fire. It basically takes the place of the ground wire in a conventional (points) ignition

Without the grey wire from the module, the coil will not fire. Check the module wiring harness, you'll see one of the wires coming out is colored grey and make sure it's connected to the (-) side of the coil

This thread (link) has a wiring diagram in addition to a lot of good info.

Scott06 said:

Good point . I have. 2 grey wires on mine one to coil one to tach. If no wire is on net post of coil It will not fire.

can disconnect the tach wire on back of tach Or check for continuity to ground with a volt meter

Click to expand...

In a previous post you mentioned removing the tach wire from the neg post will remove the tach as a possible issue. That is the only wire on that post. Removing it leaves nothing on that post. All my testing was done with the tach wire on. I removed it and tried it like you mentioned. It didnt help so I put it back on. Now I'm hearing there should be 2 wires on neg post? I didnt see any other grey wire coming out of the harness The distributor module ground gets grounded at riser like it was before I started. Is there supposed to be a ground on the Neg post of coil? Can I run a wire from neg post to neg battery post for testing? My biggest fear is frying something like the no longer made ignition module running test wires incorrectly

If y

jonny rotten said:

In a previous post you mentioned removing the tach wire from the neg post will remove the tach as a possible issue. That is the only wire on that post. Removing it leaves nothing on that post. All my testing was done with the tach wire on. I removed it and tried it like you mentioned. It didnt help so I put it back on. Now I'm hearing there should be 2 wires on neg post? I didnt see any other grey wire coming out of the harness The distributor module ground gets grounded at riser like it was before I started. Is there supposed to be a ground on the Neg post of coil? Can I run a wire from neg post to neg battery post for testing? My biggest fear is frying something like the no longer made ignition module running test wires incorrectly

Click to expand...

What Is the serial number of the engine ? Yes normally there are two wires on negative side of coil one to ignition module one to tach. But yours may be different hence the serial number

If you ground the negative side of the coil you will kill the spark.

You can always take the signal wire off back of tach to take the tach out of the picture and continue on with the trouble shooting guide

The TBV ignition module has a gray wire (among others) coming from it which goes on the Neg post

jonny rotten said:

Now I'm hearing there should be 2 wires on neg post?

Click to expand...

Post #28 and the link in post #29 have all the information you are seeking

Good luck

Jonny,
Please pardon my dog piling on this one.
First some fundamentals:
The Ign Coil has +12V on the + terminal (so when the key is on / start it has power) and on the other side (the negative terminal) is a switch that opens and closes as the motor turns. When the switch is closed the coil ‘powers up’ and when the switch opens it releases that power as a spark for the plugs.

• If the switch never closes, there is no build up of power and thus no spark.
• If the switch never opens, there is no release of that power and thus no spark.

See mock up below.
Your negative terminal should have 2 wires going to it

• One for the switch
• Other for the Tach

It’s possible for the Tach wire to short out overriding the switch from opening, thus no spark. This is why the first step in the Troubleshooting (T/S) guide is to check that wire. No need to unbundle it from the wiring harness, just use a Multimeter. But easier to simply remove it, leaving only the switch wire connected.

That switch in your system is contained in the module that looks like picture below.

What is going on with your situation is that the switch wire from the module is not connected to the coil.

Thus, your mission is to find it, because its there unless it got cut off somehow.

Here is how to find it: Look at that plug from the module, it may come out in more than one bundle, I am unsure. Follow each of those bundles as best you can and see if you find a wire one that comes out of that bundle and looks like it connects to the coil, is close enough to connect and is gray. That would be it. Connect it (but leave the other one off) and fire it up!

More: Post No. 10 said had a disconnect black wire. Is it possible that it’s not black and is the missing switch wire?

dubs283 said:

There should be two grey wires connected to the (-) side of the coil

One for the tachometer signal and one for the module

The one for the module provides the "pulse" to let the coil fire. It basically takes the place of the ground wire in a conventional (points) ignition

Without the grey wire from the module, the coil will not fire. Check the module wiring harness, you'll see one of the wires coming out is colored grey and make sure it's connected to the (-) side of the c

Click to expand...

Scott06 said:

If y

What Is the serial number of the engine ? Yes normally there are two wires on negative side of coil one to ignition module one to tach. But yours may be different hence the serial number

If you ground the negative side of the coil you will kill the spark.

You can always take the signal wire off back of tach to take the tach out of the picture and continue on with the trouble shooting guide

Click to expand...

Serial # 0l072052

dubs283 said:

There should be two grey wires connected to the (-) side of the coil

One for the tachometer signal and one for the module

The one for the module provides the "pulse" to let the coil fire. It basically takes the place of the ground wire in a conventional (points) ignition

Without the grey wire from the module, the coil will not fire. Check the module wiring harness, you'll see one of the wires coming out is colored grey and make sure it's connected to the (-) side of the coil

Click to expand...

This is the only before pic I have. It sure looks like only one grey wire attached to post. Got my head back there and see no other wires coming from the harness. Highly unlikely it got clipped pulling motor. The grey looking wire in the foreground is the black and for the distributor sensor which is new

jonny rotten said:

This is the only before pic I have. It sure looks like only one grey wire attached to post. Got my head back there and see no other wires coming from the harness. Highly unlikely it got clipped pulling motor. The grey looking wire in the foreground is the black and for the distributor sensor which is new

Click to expand...

The two grey wires are bonded inside the harness, so only one is hitting t(e negative post of the coil. Attached is a wiring digram for your engine (assuming alpha version).

so go through the troubleshooting after disconnecting the signal wire at the tach.

Scott06 said:

The two grey wires are bonded inside the harness, so only one is hitting t(e negative post of the coil. Attached is a wiring digram for your engine (assuming alpha version).

so go through the troubleshooting after disconnecting the signal wire at the tach.

Click to expand...

I'm going out there now step by step with the scratch test. Just want to confirm when using a test light on the negative post of coil to see if it lights up while cranking, the test light lead goes to positive battery terminal. Also have a new distributor sensor will try out

Jonny,
We should have picked up that for the version “V” of the ign system bonds the 2 gray wires inside the wiring harness as Scott mentions, thus only one gray wire to neg post of coil. Sorry for that.

Thus, the T/S guide does not work for version V unless you disconnect the plug at the module as well as at the coil. Let me explain: its possible the tach is grounding the system overriding the ‘switch’ as I explained in post no. 34. So, to test that, since the ‘2 gray wires’ are connected inside the wiring harness and it’s not possible to separate them, need to unplug the module and take the gray wire off the coil. Thus, the only connection left on that set of wires is the Tach. And if it’s shorted to ground, the tach (or a short inside the wiring harness) is the issue. See wiring mockup below.

Here is how: once it’s unplugged from the module (if more then one plug, unplug both) and disconnected fm the coil, set your multimeter (MM) to the continuity setting and with one probe connected to the gray wire and the other to ground, does the MM beep at you? If yes, then the tach is probably shorted out so do this: under the dash disconnect the gray wire from the tach and make sure it’s not touching anything and test again. If no beep, yeah! Hook back up the coil and module and start it up. If still a beep, bummer, the wiring harness is somehow shorted out. Post that situation and a workaround can be done.

I am unsure of the rest of the T/S guide for a version V as one of the steps is to disconnect the WHT/RED “bullet” connector from the distributor. Perhaps version V has multi-wire plug vs single wire bullet connectors thus making this step not valid.

Can you take a few pictures of the connections at both the distributor and module to validate how these connections are?

Nice pic but he has a TBV
Wire colors are the same, just more of them