Engine Keeps Losing Spark.... WHY ?

[Yinzer]

26 minutes ago, datzenmike said:

 

The module is grounded through the two mounting screws.

 

You could run a 4 wire but 2 plugs per cylinder is there and it's more efficient. That's going backwards. A single plug will burn slower so the ignition will need to be advanced to 10-12 degrees BTDC to give it enough time to complete the burn and build it's maximum cylinder pressure at that sweet spot at about 15-17 degrees ATDC.

Ok, makes sense.

 

BTW... It's ONLY 120 degrees REAL FEEL now outside  !

[Yinzer]

I had a chance to run a jumper wire from a distributor cap screw to an a metal panel. Got continuity. Tried to start..... NO spark.

 

How do I check the signal coming from the ICM to the Coils ??

[Yinzer]

I noticed some scratch marks on the side of the rotor. Thought that was odd. Ordered a new rotor. Will be here Tuesday.  ??

[datzenmike]

The module doesn't really signal the coil. The module is a path to ground that opens and closes. When closed, current flows through the coil to ground energizing it. When it opens the coil discharges a spark. With the ignition on, touch a ground to the negative side of the coil and if the coil is working you should get a spark.

[Yinzer]

17 hours ago, datzenmike said:

The module doesn't really signal the coil. The module is a path to ground that opens and closes. When closed, current flows through the coil to ground energizing it. When it opens the coil discharges a spark. With the ignition on, touch a ground to the negative side of the coil and if the coil is working you should get a spark.

 Will do.

[Yinzer]

 Yes, there is Spark from NEG side of both Coils to Ground. Not real strong, but there is spark present.

 

 I believe the POS Side of the Coils were showing around 10.5 Volts while my wife was turning the key. Need to double check that again.

 

 Were does the POS sides of the Coil wires lead back to ?? How about the NEG Sides ?

 

 I believe they go back to the ICM IIRC.... I want to check the continuity but the wire colors are different coming out of the distributor back on up to the Coils and Ignition. Not sure where the other wire goes to. Stater Solenoid perhaps ??

 

 This truck was rewired and I think whomever did was inconsistent with wire coloring. I believe they just got stuff wired up to get it running. Dunno........ ??

 

 Also, I believe the wire going to the BLADE Tab on the Solenoid is loose. I can't access it to good how the truck is sitting.... In mud and gravel and crap...

[datzenmike]

Power directly from the ignition in the ON position goes to the intake coil POS terminal and the power for the ignition module in the distributor. Power for the exhaust coil comes from the first fuse on the far left side of the fuse box, also powered from the ignition switch in the ON position. Both NEG sides of the coils go the two of the terminals on the ignition module.

 

Which terminal on the module is which, I don't know. (I think) the positive is in the middle with the coil negatives on either side. Don't quote me on this.

[Yinzer]

6 hours ago, datzenmike said:

Power directly from the ignition in the ON position goes to the intake coil POS terminal and the power for the ignition module in the distributor. Power for the exhaust coil comes from the first fuse on the far left side of the fuse box, also powered from the ignition switch in the ON position. Both NEG sides of the coils go the two of the terminals on the ignition module.

 

Which terminal on the module is which, I don't know. (I think) the positive is in the middle with the coil negatives on either side. Don't quote me on this.

Gotcha. I'll double check all that.

 

 There is something draining down my battery while it's off. The battery is only 6 months old and I recently had it loaded tested at a battery shop. I need to recharge the battery nearly everytime I'm done working on the truck. Trying to start it many times.

 

 There is an issue (I mentioned way back in this thread) when starting (OCCASIONALLY) sounded/acting like the batter is way worn down and the starter barely turning. Like I mentioned earlier.... it does NOT do it everytime I crank the engine but does it RANDOMLY. The next time I turn the key after this happens, the starter spins as it should and the battery doesn't sound like it's worn down. 

 

 A couple things I can think of is the wire going to the Solenoid. BLADE style connector

[Stoffregen Motorsports]

The entire truck was rewired? Or just parts and pieces? It may seem reasonable to keep at it like you are, but at what point do you just source an entire harness and start over?

[datzenmike]

Random poor cranking of the starter...

 

Battery cables, poor connection to the battery posts, poor ground to intake, poor connection to the starter lug. Starter poorly grounded, bad solenoid.

 

I assumed that you would have looked carefully at this. Start signal from ignition won't cause this. It either works the solenoid or it doesn't. Not working may include chattering.

 

 

[stuart720]

On 6/24/2023 at 3:58 PM, stuart720 said:

Be sure to pop the distributor cap and give the wires going to the module at the base a good look over connections and all.

 

The vacuum advance system inside sometimes moves or even breaks the wires. Very poorly designed if you ask me. Had this happened to all 4 or 5 wires on my own. Spin the advance system by hand and where it stops is where the break happens. Had to lengthen an reroute 

 

Had this exact same problem... mentioned this earlier...

[Yinzer]

On 8/10/2023 at 10:49 AM, Stoffregen Motorsports said:

The entire truck was rewired? Or just parts and pieces? It may seem reasonable to keep at it like you are, but at what point do you just source an entire harness and start over?

I don't really know for sure. I do know all the Emissions stuff was deleted. The work looks like it was done by someone with a brain. Very good quality connections, care to detail and not cut, hacked in caios. 

[Yinzer]

On 8/10/2023 at 11:15 AM, datzenmike said:

Random poor cranking of the starter...

 

Battery cables, poor connection to the battery posts, poor ground to intake, poor connection to the starter lug. Starter poorly grounded, bad solenoid.

 

I assumed that you would have looked carefully at this. Start signal from ignition won't cause this. It either works the solenoid or it doesn't. Not working may include chattering.

 

 

 I've recently rewired all the cables from the battery. Redid and added a couple grounds as well. I still have to get up under it and check the solenoids blade connector. I was really happy the way it felt when I initially connected it. Felt bit loose. I can't really access the area as the way the truck is currently sitting. Can't get a floor jack up under as it's sitting on soft dirt right now. Can't move the truck to a better spot either. Just kinda fucked where it sits. 

[Yinzer]

On 8/10/2023 at 6:55 PM, stuart720 said:

 

Had this exact same problem... mentioned this earlier...

 Been doing just that about 10 times already. I'm going to pull the distributor here shortly and sand down the areas where it contacts the block to ENSURE that SOB has good ground.

 

 Also, what is the purpose of the SPADE connector attached to the distributor that sits directly next to the vacuum advance unit ? Looks to me from my Haynes Manual (that I just found) to maybe be a GROUND connection. ?? Dunno....

[Yinzer]

[datzenmike]

2 hours ago, Yinzer said:

 

 

 Also, what is the purpose of the SPADE connector attached to the distributor that sits directly next to the vacuum advance unit ? Looks to me from my Haynes Manual (that I just found) to maybe be a GROUND connection. ?? Dunno....

 

YES  it's a ground!!! If it's there find the connector for it or make one and ground it to... an exhaust manifold bolt.

[Yinzer]

2 hours ago, datzenmike said:

 

YES  it's a ground!!! If it's there find the connector for it or make one and ground it to... an exhaust manifold bolt.

 Ok, thought so. I'll go check it again to see where it leads to.

[Yinzer]

The wire (black 2 red stripes) coming off the Spade connecter goes into this fitting. What is this connection? 

 

 Also, what are these connectors next to the Driver's side inner fender for ? All the Emissions parts have been removed by the PO. Does my truck really need all this ? 

 

I just want to get the basics fixed to get this truck running again. 

[Yinzer]

Still too damn humid and hot to work outside. Short windows in early AM and later PM. Frustrating....

[Yinzer]

22 hours ago, datzenmike said:

 

YES  it's a ground!!! If it's there find the connector for it or make one and ground it to... an exhaust manifold bolt.

 Ok, thought so. I'll go check it again to see where it leads to.

[Yinzer]

 Where does the Tachometer signal generate from ?

 

 Upon cranking, my truck's the Tach stays STILL at Zero.

 

I've read that it should register at least 3-400 RPMs while cranking. 

[stuart720]

Check the wires too. I had to do a continuity test to find those broken wires. About 2" or so back from the spades.

 

The vacuum advance inside moves when driving. My wires were bunched up next to it and when it engaged, it hit the wires over and over again.

 

Stuffed the wires back as best as I could, and after a drive, it wouldn't start, popped the cap an the advance hit the wires again.

 

That's when I redid them, slightly longer and ran 2 on the left and 2 on the right 

[stuart720]

Both your coil signals come from that moduel, if everything around it is checking out, id hit the junkyard and find 2 or 3 to swap and test