Happy New Years and ignition wiring questions

[Gary Lewis]

I believe we have discussed the location before but I don't think that should matter. I don't think there is any reason to go into the dash. If the wires in the engine bay are still in good shape, I should be able to splice the new harness right into them out there.

Right. The resistance wire is in the dash, so if you can splice in the engine bay you are good.

[dirtymac]

Right. The resistance wire is in the dash, so if you can splice in the engine bay you are good.

Ok great. That is currently the plan. We are throwing a birthday party for a friend today and we are under a severe heat advisory the next two days so I don't expect to get far this weekend but the plan is in the works.

[dirtymac]

We may be getting back on this little project soon and I have a few things to follow-up on.

First question is about the resistance wire. I haven't found it yet but after looking through pictures and the EVTM I believe I know where it is. If the portion of the wires going into the dash are still in good shape, there should be no reason I can't just splice the new harness into them?

Second, I am looking for a replacement coil and I'm considering the Standard Motor Products SMP-FD476 and the NAPA Echlin ECH IC21. I can get the NAPA part locally pretty easily. The SMP I'd have to order from Summit ($20) because O'Reilly currently wants a staggering $72. Has anyone used either and have anything to say about them?

Third, I may not change the Duraspark II module immediately but it's on my list and I'd like to go ahead and get a spare. I'm considering the NAPA Echlin ECH TP40.

Jim, I found a thread where you mentioned having the SMP-FD476 and the Echlin TP40. Are those still working for you?

We had a look over the wiring this morning. There is a 3rd pigtail spliced in with the 4-wire Duraspark pigtail that we are unsure of. We had a look at the EVTM and we belive it is for the 3.8L choke relay and Tach return.

We can't read the wires because of the gunk and tape. It's all brittle so we are hesitant to mess with it too much. I'm attaching pictures of the area and the diagram from the EVTM. Is this what we think it is?

[ArdWrknTrk]

We had a look over the wiring this morning. There is a 3rd pigtail spliced in with the 4-wire Duraspark pigtail that we are unsure of. We had a look at the EVTM and we belive it is for the 3.8L choke relay and Tach return.

We can't read the wires because of the gunk and tape. It's all brittle so we are hesitant to mess with it too much. I'm attaching pictures of the area and the diagram from the EVTM. Is this what we think it is?

It's coming from C322, the distributor connector?

Black & green is definitely the tach signal, plus the only ground for DS-II...

Orange and purple are for the reluctor pickup

[dirtymac]

It's coming from C322, the distributor connector?

Black & green is definitely the tach signal, plus the only ground for DS-II...

Orange and purple are for the reluctor pickup

Yes, this third plug is coming off of C322. I didn't notice the these were grounds but now that you've said it, I see it.

[ArdWrknTrk]

Yes, this third plug is coming off of C322. I didn't notice the these were grounds but now that you've said it, I see it.

The bk/Lg wire is the ground tab just inside the distributor.

When the blue grommet module breaks that ground the coil fires, and the tach gets a signal.

 

[dirtymac]

We took the plunge today and removed the factory ignition harness. We replaced it, the coil, the Duraspark II and cleaned things up a bit.

Here are a few notes on what we did and and how things stand:

1) I do think the Painless harness was worth the money. I believe most of the pigtails are available if you want to rebuild this from scratch.

2) Our factory harness was a complete mess. Split, cracked, patched, and corroded throughout. We also decided to replace the coolant temperature sensor pigtail and the oil pressure sending unit pigtail. Both were in awful shape.

3) The factory wires providing power through the ignition were in good shape inside the engine compartment. Instead of running all new wires to the ignition relay, per the instructions, we opted instead to tie those wires into the factory wire harness. We removed the factory pigtail in order to do this.

4) We opted to tie the ballast wire into the factory wire harness in the engine compartment as well.

5) The brown wire included in the package wasn't necessary for our factory setup. This wire is used to bypass the ballast resistor during startup. According to what we found in the forums and elsewhere, this is already provided by the factory ignition switch.

6) We didn't cut any length of wire we didn't have to. Instead, we wrapped spooled all the excess wire for future use.We also wire loomed everything.

7) Something that has bugged me since we got the truck was a pile of what looked like tar all over the driver's side wheel well skirt. I believe this mystery has been solved. I'm pretty confident that at some point the resin seal on a previous Duraspark module melted and solidified in place. I was able to remove most of it but there are still bits left.

[ArdWrknTrk]

We took the plunge today and removed the factory ignition harness. We replaced it, the coil, the Duraspark II and cleaned things up a bit.

Here are a few notes on what we did and and how things stand:

1) I do think the Painless harness was worth the money. I believe most of the pigtails are available if you want to rebuild this from scratch.

2) Our factory harness was a complete mess. Split, cracked, patched, and corroded throughout. We also decided to replace the coolant temperature sensor pigtail and the oil pressure sending unit pigtail. Both were in awful shape.

3) The factory wires providing power through the ignition were in good shape inside the engine compartment. Instead of running all new wires to the ignition relay, per the instructions, we opted instead to tie those wires into the factory wire harness. We removed the factory pigtail in order to do this.

4) We opted to tie the ballast wire into the factory wire harness in the engine compartment as well.

5) The brown wire included in the package wasn't necessary for our factory setup. This wire is used to bypass the ballast resistor during startup. According to what we found in the forums and elsewhere, this is already provided by the factory ignition switch.

6) We didn't cut any length of wire we didn't have to. Instead, we wrapped spooled all the excess wire for future use.We also wire loomed everything.

7) Something that has bugged me since we got the truck was a pile of what looked like tar all over the driver's side wheel well skirt. I believe this mystery has been solved. I'm pretty confident that at some point the resin seal on a previous Duraspark module melted and solidified in place. I was able to remove most of it but there are still bits left.

Great progress Will!

Yes, the pile of rubber is potting from a previous ignition module.

Some people don't understand how hot failing transistors can get.

"Spare wire for later" is okay in a vehicle like this without a bunch of sensitive electronics, but you're essentially creating an inductor (like your ignition coil) and with a newer vehicle you don't want magnetic fields, or back EMF when the power gets cut in that circuit.

I also don't know what all is inside that loom, but it's 'best practice' to minimize lengths of parallel wires and use 'twisted pair' for things like sensors.

None of this is criticism, it's observation, and critique.(how else can we learn?)

I think you've done a fine job.

Glad that so much of the sketchy wiring was actually alright!

[Gary Lewis]

Great progress Will!

Yes, the pile of rubber is potting from a previous ignition module.

Some people don't understand how hot failing transistors can get.

"Spare wire for later" is okay in a vehicle like this without a bunch of sensitive electronics, but you're essentially creating an inductor (like your ignition coil) and with a newer vehicle you don't want magnetic fields, or back EMF when the power gets cut in that circuit.

I also don't know what all is inside that loom, but it's 'best practice' to minimize lengths of parallel wires and use 'twisted pair' for things like sensors.

None of this is criticism, it's observation, and critique.(how else can we learn?)

I think you've done a fine job.

Glad that so much of the sketchy wiring was actually alright!

Well done!

You are right, your old harness was toast. Glad the Painless harness worked so well.

So, what's next?

[dirtymac]

Great progress Will!

Yes, the pile of rubber is potting from a previous ignition module.

Some people don't understand how hot failing transistors can get.

"Spare wire for later" is okay in a vehicle like this without a bunch of sensitive electronics, but you're essentially creating an inductor (like your ignition coil) and with a newer vehicle you don't want magnetic fields, or back EMF when the power gets cut in that circuit.

I also don't know what all is inside that loom, but it's 'best practice' to minimize lengths of parallel wires and use 'twisted pair' for things like sensors.

None of this is criticism, it's observation, and critique.(how else can we learn?)

I think you've done a fine job.

Glad that so much of the sketchy wiring was actually alright!

Thanks Jim!

One loop is the brown wire and the tach wire from the coil that are currently unused. Another loop is the two wires feeding power to the Duraspark and the resistance wire. I've tried to keep the loops large enough and loose enough as to not create any major issues.

I think once we have some other things sorted out with the wiring in that area, I will clean it all up further. We still have several broken and disconnected wires near the brake booster that need to be figured out.