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Engine harness firewall gromet

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Chris Demartini, Jun 18, 2002.

  1. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color="blue">I went to the local Chevy dealer after work to try and find the firewall gromet for the EFI engine harness, but we couldn't find it in the computer. Does anyone have a part number? Or better yet one they can sell me? /forums/images/icons/grin.gif
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Chris, what year TPI are you dealing with? Just did the square plug '88 F-body "conversion" to fit it to my '86 body. Tedious, yes, but clean. I hate cutting holes in the body anyways, there are already enough IMO lol.

    If you don't want to go this route, no problem, but it was works great.

    Get a spare heater wiring grommet (again, this was my '86, think all '73-up had the wiring on the passenger side for the heater) and set it aside.

    Take the EFI harness, and remove that square plug, then all the wires from the "glue" inside it. (this is one of the tedious parts, but easy, you just need time and some patience)


    Take the grommet, and trim most of the inner rubber out of it...its a big grommet, but only three wires going through it. One by one, de-pin each wire from the ECM plug(s), pass it through the grommet, and insert it back into the connector. This part actually goes pretty quick.

    Once you are done with the ECM wiring, all you have to do is the 3(?) wires from the heater plug the same way, and pop it in place. If worried about air sneaking past, give the grommet/wiring a good shot of sillycone.

    I *do* have the square gasket that came off of my '88 harness I believe, if you want it. Can't beleive I saved it, that was one of those parts that I didn't imagine anyone would want, but I don't think I've tossed it yet.

    I know I looked at that plug and decided there was no way I was going to cut that big of a hole in the firewall.
     
  3. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color="blue">It's a 91 TPI harness and it has the square plastic plug, if theres a way to keep it, I would like to. I'm not afraid to cut the hole for it in my firewall, but I need it closer to the engine end of the harness than it is now. If I put it in the way it is now, almost all the wiring would be in the engine compartment and the ECM would be right against the firewall. I got the gray half of the plug off pretty easy, but the black half is giving me trouble. I guess I have to cut it out of the silicon. I should be able to re-use it, right?

    Also, my ALDL harness is only about 8" long and it has a white plug on the end, not a data link connector. Is there another peice of that harness with the data link connector on the end? I will try and get a picture.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    There are 3 "passenger compartment" side connectors. 2 are for the ECM, the 3rd connector (white, there ARE male/female ends) is a bunch of other wires ganged together. Fuse panel power, 3 or 4 ALDL wires, (out of 6 or 7 total on the ALDL) etc. Not really sure why GM ganged those all up like that on the female (? or male) end, but they did. From the mate of that connector, IIRC, all wires loop into the ECM connectors. (might be some that go engine side too, not sure)

    As to the plug, sounds like you are going to have to ditch it. That stuff isn't quite silicone, its harder. Apparently you can heat it with a hair dryer to make it easier to deal with, but with patience and time, a jewelers flat blade screwdriver will free all the wires from their encasement.

    If you look closely once you get the half of the plug off, you'll see over the top of the wires (also encased in the clear stuff) a white nylon piece. It has "tines" (like a fork) that extend down to the bottom of the "stuck" half of the plug, seperating some of the wires. As you pull away wires (start on one side) you will see a tine. Pull the tine free, and cut it out of the way. Proceed all the way through like this. As far as I could tell, the clear stuff is somehow bonded to that plug, and there is NO way to get it out. I assume it flows into nooks and crannies when "cast" and anchors itself too well. You could try heating the entire thing up so it broke free, but I imagine that would start to harm the wire insulation. Then you get to the point that you can't replicate that factory goo, so yet another problem. I liked the plug design, (stout, weather tight seal) but it simply wasn't made for the trucks.

    Even cold I could get the wires out with the fine screwdriver, just had to be very careful to not cut the wire sheathings.
     
  5. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color="blue">Is that white connector you're talking about the IP connector that I keep seeing on my diagrams?

    [​IMG]
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Well its more clear than white I guess, but I imagine we are talking about the same connector. Still not where I can look at the harness, but this connector has the "upshift" light in it, on my manual trans harness.

    I gotta take off, so no time to look at this, but do you have a factory wiring harness you are dealing with?

    http://92b4crs.tripod.com/86wiring/86wiringindex.html

    I've got the '88 F-body Service Manual (finally) and the '88 Electrical Diagnosis Manual, so when I head home tonight, I can at least give you some '88 info if necessary.

    http://92b4crs.tripod.com/86wiring/86wiringindex.html
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    BTW, you are correct, the white (clear in my case) IP connector on my '88 harness is that one. The female side of that connector is black.
     
  8. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color="blue">Know where I can get a part # for that connector?
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Hmm..might be in my parts manual, but I did forward this to a friend of mine that might be able to get one. Let me know if you don't hear anything from him in a day or so.
     
  10. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color="blue">I went to the junkyard today and got the other end of the I/P connector out of a camaro. I also got the ALDL. I looked for a heater gromet but I couldnt find one, but then on my way out of the yard I found a gromet on the ground /forums/images/icons/laugh.gif that will work. When I got home I drilled out the middle a bit and cut it from the middle out so I could fit it over my harness. It fits great so I can use that. Another question, on the external coil I got there are two plugs that connect to it. One goes to the distributor, and the other goes to ignition power and tach. Which is which? /forums/images/icons/confused.gif They both look the same
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, nice you found a grommet!

    On the coil though, I was just playing with mine last night...one does indeed go to the distributor, and one is ignition/tach. Mine is "keyed" though...I don't have it here in front of me, but if you have the coil, (and if its like mine!) set it so the shiny metal fitting (looks to be vac fitting to me) is on the right as you are looking at it. You should also be able to see where the two plugs go from here, correct? On mine, the ignition/tach plug actually is a two pronged connector, whereas the dist plug IIRC is set up differently. My ignition/tach plug is gray. It also appears that if I install the dist. Plug first, the ignition/tach plug overlaps it, essentially locking it in place.

    I've found some differences in wiring based on engine VIN (F vs 8 in my case) the same year, so I'm not sure that your plugs/coil, etc., will all be the same.

    If you want, check out www.carparts.com, and see if they list the same coils for an '88 and '91 V8 camaro. (VIN 8 I assume) If so, let me know, and I can take a peek when I get home late tonight.

    Couple of plugs on mine I've gotta figure out too...got both manuals and still no help lol. I wish the diagrams were laid out like our old truck ones...it may have been a big tangle of lines, but at least you could see what went where, and how everything interconnected. GM went kinda cheap/dumbed down on the newer manuals IMO.
     

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