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TBI won't fire up

I just went out and tore into it a little deeper. I'm kind of confused on how to map the wires I have to the connections I need on a new distributor. The distributors I'm seeing have 2-pin and 4-pin exposed connectors. My current thing has wires going into the distributor base, one group of 4 and the other a group of 3. It appears that the module still has 4 and 2, but the third wire is grounded in there. Plus there's that capacitor. Anyone understand this well enough to know how I would adapt to the simpler seeming 2 and 4-pin connectors?

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This is what I'm talking about BTW:

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I have to plead ignorance at this point. There have been a lot of sleeps sense this all started. What are you working on? I am not familiar with that dizzy on TBI.
 
Much misery has come to me over the years as a result of hiring someone to help me convert my truck to TBI. He didn't just have me put a full TBI truck system in, but seemingly adapted my coil in cap system to TBI. I did replace the distributor base/body, but kept my original cap and coil. Maybe this distributor is from a car application or something. My truck is having intermittent no-start situations, so I'm thinking about what it would take to swap in new parts and make it "normal" so it matches something like a 1990 GM truck application. I just need to figure out how to map my current wires to the new connections.
 
Your current dist should use a normal big cap hei coil.
You can try that.

The module in the 2nd pic is standard tbi, small cap distributor.
You will need the small cap distributor, and make the connections to the ECU. Metric weather pack connectors and tools.
 
ACDelco Professional PT2386 Multi-Purpose Wire Connector with Leads , Black https://a.co/d/3b7uImR

ACDelco Professional D503A Ignition Coil https://a.co/d/5NFZLsM

ACDelco Professional PT1909 Ignition Coil Pigtail , Black https://a.co/d/g4PBr2Z

So these are a start there are two more connectors and the dist.
Someone is blowing up my txt need to post and check it
 
ACDelco Professional PT2386 Multi-Purpose Wire Connector with Leads , Black https://a.co/d/3b7uImR

ACDelco Professional D503A Ignition Coil https://a.co/d/5NFZLsM

ACDelco Professional PT1909 Ignition Coil Pigtail , Black https://a.co/d/g4PBr2Z

So these are a start there are two more connectors and the dist.
Someone is blowing up my txt need to post and check it
Thanks for the help. My issue is that I don't know what to hook to what. It's because I have extra wires on the current setup compared to what the standard truck setup has. The 3rd wire on the right side is one, then externally, that red wire is actually spanning the group of 4 and group of 3. You can't tell that in the picture, but something is going on there.

The more I think about it, the guy who I hired really F'd me with this. You can see that this is not a computer controlled distributor since it has provisions for weights and springs. It's like he took a carb distributor and somehow put a CC module in there or something...
 
The old dist, wires from dist to cap forget about those.
The other batch that connect to loom. The loom side wires will need to be identified and will connect to new module.
The loom wiring to old cap will go to new coil. Then coil to module connection.
Will take some head scratching and be sure document diagram for less confusion
 
ACDelco Professional PT2386 Multi-Purpose Wire Connector with Leads , Black https://a.co/d/3b7uImR

ACDelco Professional D503A Ignition Coil https://a.co/d/5NFZLsM

ACDelco Professional PT1909 Ignition Coil Pigtail , Black https://a.co/d/g4PBr2Z

So these are a start there are two more connectors and the dist.
Someone is blowing up my txt need to post and check it

This is a huge help! These constitute everything to go from distributor/module to coil, and coil to tach/batt, correct? What are the other two? I only count one more, the one to the 4-pin connector on the module. I may have this on my harness already. I have a 4-pin Delco connector there, just a matter of whether it's the right one.
 
It is almost. Yes the 4 pin if still in loom is great should be just plug and play, unless pins were moved in connector. There is 1 more coil plug I haven't yet found, I'm sure it's available some where.
 
Man, seeing as you have TBI, I'd definitely swap over to the proper distributor.

I see zero reason to not let the ECM control timing when it was made for it. Of course, maybe the knock sensor circuit was dispensed with as well, which could cause other issues.
 
This thing is controlling timing. It's all legit in its way, just not a normal truck TBI setup. But yes, I totally want to make it standard if I can figure out which wires go where.

Someone on thirdgen recognized it and thought it was fine, maybe like a common way to do conversions back in the day. But I want to be able to look at factory diagrams and have stuff match.
 
You've used the factory diagrams for the various TBI year's to start to figure that out? Should be relatively simple, it runs, so everything has to be there I suppose.

Never heard of that being a thing, but when things are new, they cost more, so converting things like that I suppose made sense at one time.
 
You've used the factory diagrams for the various TBI year's to start to figure that out? Should be relatively simple, it runs, so everything has to be there I suppose.

Never heard of that being a thing, but when things are new, they cost more, so converting things like that I suppose made sense at one time.
I guess I'll have to just dig in deeper. I was hoping for a 1:1 between connections now and on the new setup. Maybe some connections just go away, or whatever. I guess my initial hope was that the connections were all the same, just going someplace different. Maybe that's not the case.

I think I did this conversion around 1996 or 1997. Perhaps there was significant money to be saved by not putting in relatively new parts or something. I bet my old posts are still on here. I went with some fly by night place called CustomEFIs when I should have probably used Howell, or just figured it out myself.
 
Just as an idea, are there still 1995 and down trucks in the wrecking yards? Find one with a butchered/burnt harness and take the distributor and clip the wires to it as far back as possible. Could grab the coil and it's leads as well.

Those trucks used to be all over the yards, so the wiring/connectors used to be super easy to find.
 
That slot-head screw in the rotor mount, plus the fact there are no springs, makes me think the mechanical advance has been locked out and the ECU is doing the timing. That may be simpler than how I did it here: https://ck5.com/forums/threads/i-go...-done-update-distributorless-ignition.181264/
Yup, I'm sure this is some sort of home brew adaptation of a mechanical advance distributor. The ECM is absolutely doing the timing though. I now fully intend to make this "normal" with a ~1990 factory style distributor and external coil. Just need to find the time and gather up all the parts (mostly connectors and coil mounting). I'm hoping once I tear into it, it will be obvious where the connections go. My ECM is not currently wired up totally as factory I don't think, like the main power and such, so there are some traps I could fall into trying to make this work.
 
Well, over a year later I'm gathering goodies to get a proper TBI distributor installed. I sprung for the DUI distributor and coil, and Painless (painful price) connection from distributor to coil. Connector for power/tach was readily available.

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4-pin connector is *not* readily available, but I found this one on ebay:

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All I'm missing is the "plug wire" for the coil.

I'll need to remember how to get the distributor out and in without totally butchering the timing, and then remember how to set the base TBI timing. I'll also need to figure out how to mount the coil. It's on the head from the factory?
 
Wow total forgot about this thread. The coil normally mounts to the intake behind the tbi. you may need a bracket, maybe not.

Pro tip get the old cap complete outta your way, leave the rotor on. put engine on #1 tdc compression stroke. Mark which cylinder the rotor is pointing to.
Loosen hold down and slide it away from dist. You can turn the dist body all you want, spray a little light penetrate oil at the seam of the dist and intake turn the body a few times, this helps wash any oil scum build up away. Start to lift the dist body slowly, as you do you'll see the rotor turn, at @ 1/2" the drive tang will come out the slot on the oil pump and little bit after that the gears will disengage. Mark where the rotor is pointing at this time, this where you want your pointing when you begin to install the new dist. As it slides in the rotor should turn back to original spot you marked before you loosened the hold down. Some times the oil pump drive tang won't slot in right away, a little wiggling of the dist body and rotor, with out loosing the gear mesh, will get to go. Make sure the dist body is fully seated, rotor is pointing where you marked it, and put the hold down back snug but not tight. When ready to time you need to disconnect the timing connector, Spec is 0° I like 2-4°, but if the knock sensor circuit malfunctioning 0° is best. tighen the hold down plug timing bypass back in. Good to go
 
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