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canadianveedub Samba Member
Joined: January 28, 2013 Posts: 40 Location: Edmonton
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Posted: Fri Sep 13, 2013 10:15 pm Post subject: Rebuild Your FI wiring harness for less than $50 |
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I have almost completed my rebuild of my 1979 bus. It has been a long journey, but a very rewarding one. As I was going through all of the things that needed to be done, it became very apparent that the wiring harness had to be rebuilt. It was a hacked mish mash of a 76 and 79 harness complete with tape and pray connections.
This is a hacked in relay because they used an 11 pin relay on the 79
It certainly crossed my mind to get Kyle Automotive to build one for me, but I decided that I would take the challenge myself.
Things you need:
Parts:
Digikey PN: A27935CT-ND $0.22 each. I bought 30 and had plenty left over.
Digikey PN: A107135CT-ND $0.37 each. I bought 50 and had enough for everything including FI connectors, ECU plug, AFM, Ignition module (mine is a CA model)
Digikey PN: A100770CT-ND $0.19 each. I bought 15 and had just enough after I did a few things under the dash.
Digikey PN: A106202-ND $3.05 each. I reused all of my old ones because you cannot find colored new ones. Digikey does not carry the boots.
About 150 feet of 18 gauge wire. (I chose OG white, but I wish I had used black for grounds, red for hot etc.)
Wire markers. I used the kind you just wrap around the wire.
Tools
Crimper. DO NOT USE A CRAPPY CRIMPER OR YOU WILL BE SORRY!!!
Sorry for yelling. I have a bad ass crimper. You will want an open barrel style crimper that should be carried at pretty much any electronics shop. I bought a molex brand from an old wiring harness factory off of ebay. Regardless, it should look something like this
You can get ones that crimp both the bare wire and insulation, or ones that crimp one at a time. I have used both and prefer a ratcheting crimper that does both at once.
Crimps should look like this
You will also need wire strippers. I prefer Klein. I have had a pair for about 10 years and they are awesome.
Electrical tape
Zip ties
A bentley manual (as if I should have to say this)
How to do it.
Prepare yourself a large area. I used a table and covered it in white paper. The way you should do it is get a piece of plywood and put nails in it to hold your harness in place as you go.
Begin by laying out the harness and making a diagram of where everything goes. This will help you keep things organized. I just drew on the paper. A half sheet of 1/2 inch plywood with the nails would be ideal as you can draw on it too. You will notice on the first photo that I use a label maker to label all connections when I take a harness out. This makes it much easier to figure out what everything is.
Next, strip off all of the old covering. Use a razor blade to slit it and peel it off. Leave all rubber boots intact.
Take the hood off of the ECU connector.
At this point, if you were anal, you could check every wire to see where it goes before you start to take it apart. The OG harness has markings on all of the wires at each end that tell you where they go.
This is the scary part. Pick a wire and pop it out of the connection in the harness. It doesn't really matter which one. I started with the shortest and worked my way to the double relay connectors. This is so I could wrap the wires as each section was finished to keep things tidy.
To pop out the connector, you need to use a very thin tool to slide into the connector housing. The female contact opening looks like a square with a notch on one side. You need to slide a tool into the both and press down the retaining clip.
This is what the openings look like
It really sucks until you get the hang of it. I use a small precision screwdriver that fits in well. I have also used small tweezers that I ground down.
Trace your newly extracted wire to the ECU and write down which pin it is in, before popping it out of the ECU. If you are color coding your work, look in the bentley to see what it does.
Measure the wire and cut a new one to the exact same length. Copy the contacts on each end and use the wire markers to mark the end of the wire at the harness side. This will allow you to trace it much easier later.
Slide it back through any rubber boots or grommets that you have and connect each end.
Move to the next wire.
Now, there are many wires that either connect to the double relay or to another connector. Just deal with these the same way. You can label them however you like, but I honestly just went wire by wire so that I could not make any huge mistakes.
At the end, you will have something that looks like this
Once you are here, you will have the "oh crap" moment as you realize that you cannot get the shrink wrap over the whole concoction again. I built mine with full intention of putting split loom over it. With the split loom, I used 3/4 inch, half inch and 1/4 inch to get the whole harness covered. For the joints, you can purchase "loom tees" from waytek wire in pretty much any configuration you like.
Now, after all this long story, I forgot to take a photo of my covered harness out of the vehicle. I just got the bus running again today and the harness worked out of the chute. I had some other interesting wiring gremlins to sort out, but none were harness related.
Interesting side note:
As you can see from my post count, I really hate asking questions on forums. I actually use the search function. This was a hard one to track down.
The 79's do not use ballast resistors. This often means that the injectors are high impedance. As I had mentioned earlier, I have a 76 reman long-block in my 79. I measured the injectors and found them to be about 2.5 ohms. One place that I was reading (and I think possibly on the forum too) stated incorrectly that the resistance is built into the wiring harness. This is not true. One of the l-jet manuals that I found states that the later models do not use resistors, but use "peak and hold" which is where the ECU sends out a strong signal to get the injectors open (peak), but then lowers the current to hold them open without syncing too much current (hold).
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added 10/16/16 thnx BayCreamPuff
Terminal Extraction Tool Set
http://www.eagleday.com/ampconnectors.html
7 Position Rectangular Housing Connector Receptacle Black 0.197" (5.00mm)
http://www.digikey.com/product-search/en?keywords=A122414-ND
COVER CAP 2 WAY
http://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/880810-1/A105234-ND/2054432
Tcash
Last edited by canadianveedub on Tue Sep 17, 2013 2:27 pm; edited 1 time in total |
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77Campmobile Samba Member
Joined: June 18, 2006 Posts: 102 Location: New Hampshire
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Posted: Sat Sep 14, 2013 7:06 am Post subject: |
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Hey great post. This is excellent info. I will rebuilding my harness as well when I get to the portion of the resto.
I did some research on how to do it and I found that alot of people use the nail board method i.e. they have a wall or large vertical work table with nails in it. The nails are used to wrap wires around and make branches/terminations at the correct locations.
I am going to do this on the wall of my garage by taking the old harness and laying it out with nails to hold it, label everything and then run the new wires using the nail pattern. Very similar to your table method.
Anyways, hers a picture of what i'm talking about. This isnt mine or even a car harness just a google image search.
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Mr. Unpopular Samba Member
Joined: September 20, 2005 Posts: 3715 Location: Tampa Florida
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Posted: Sat Sep 14, 2013 7:51 am Post subject: Re: Rebuild Your wiring harness for less than $50 |
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canadianveedub wrote: |
One of the l-jet manuals that I found states that the later models do not use resistors, but use "peak and hold" which is where the ECU sends out a strong signal to get the injectors open (peak), but then lowers the current to hold them open without syncing too much current (hold). |
Coming from the mustang world, they sometimes refer to high impedance injectors as "peak and hold" _________________ "In any racing engine, the nearer you are to it disintegrating, the better it's performance will be"
-Keith Duckworth, creator of the Ford/Cosworth DFV |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21512 Location: Oklahoma City
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Posted: Sat Sep 14, 2013 1:46 pm Post subject: |
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A couple of notes.....no picking at you...just adding some info that should help.
The type of crimper used is spot on. If you cannot afford a good one....get a cheap one...but it must be compound and ratcheting.
the best crimper dies are made by Paladin tools. Their crimper frames/handles are a few notches above as well. Many other like Klein, IDEAL, Greenlee and Eclipse/ Lunar are knock off's of the Paladin.
The key here with all of these be they knocks or not...they all take the same die pattern so Paladin and other knock off brand dies will interchange in any of these.
Th Rhino brand is good quality but takes a unique die pattern. It may be hard to get what you need if you need it.
Also....there is actually quite a science to crimping. Solder will never beat it for consistency and longevity. There is an entire worldwide technical association built around the crimping industry with huge technical resources and date and training available.
A proper barrel crimp will squeeze all air out from between the wire strands in the barrel and make a uniform cross section that can hardly be discerned as stranded.
A note....that will help the crimped connection last longer without internal corrosion.....is to strip the insulation to the exact proper length so that small ends of the strands are not sticking out on the connection side.
The stray strands bend around and can allow moisture to wick into the face of the crimp causing high resistance.
Also...even better hygiene is to then heat the crimp just lightly...maybe 165-175F to dry it and then apply circuit board varnish to seal it. The heat helps it dry fast. this seals any moisture ingress area.
Nice write up! Ray |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Sep 14, 2013 3:04 pm Post subject: |
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I like what you have done. Two small suggestions. There is a wiring place that I think Randy in Maine has posted a couple times. They have wire colors of many kinds and gauges. You have to hold true to the gauge used originally for several reasons - too much current can burn the wire up before the fuse and too thin and you get voltage drop.
Napa can order the FI boots. |
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WendyArmbuster Samba Member
Joined: March 03, 2006 Posts: 330 Location: Springfield, MO
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Posted: Sat Sep 14, 2013 5:38 pm Post subject: |
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Awesome writeup! The Digikey part numbers all in one place on the forums is top notch work! Thanks! _________________ Brian Z
1978 Westfalia |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Sat Sep 14, 2013 7:24 pm Post subject: |
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which contacts/connectors did you use for the ECU plug? The small/narrow female spade connectors pictured? _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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canadianveedub Samba Member
Joined: January 28, 2013 Posts: 40 Location: Edmonton
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Posted: Sun Sep 15, 2013 12:00 am Post subject: |
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The ECU plug connectors are the ones with small square ones that look like they have 4 separate tines to them.
As to the gauge, 18 gauge is the closest to the OG wire used. It is actually slightly larger.
Waytek wire or Del City are the two best places I have found as online wiring suppliers, however, they do not usually carry the proper connectors.
Does anyone have a PN for the boots?
I am pretty passionate about fuel injection. I built my first megasquirt EFI when I was 21 and I have manufactured VW TDI performance electronics (hence my love of wiring harnesses). I know that it does not seem as simple as carbs, but once you get it running right, everything gets so easy. I honestly would rather spend a day electrically troubleshooting a no-start than doing any sort of mechanical work. |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Sun Sep 15, 2013 9:22 am Post subject: |
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canadianveedub wrote: |
The ECU plug connectors are the ones with small square ones that look like they have 4 separate tines to them.
As to the gauge, 18 gauge is the closest to the OG wire used. It is actually slightly larger.
Waytek wire or Del City are the two best places I have found as online wiring suppliers, however, they do not usually carry the proper connectors.
Does anyone have a PN for the boots?
I am pretty passionate about fuel injection. I built my first megasquirt EFI when I was 21 and I have manufactured VW TDI performance electronics (hence my love of wiring harnesses). I know that it does not seem as simple as carbs, but once you get it running right, everything gets so easy. I honestly would rather spend a day electrically troubleshooting a no-start than doing any sort of mechanical work. |
check out my website in my sig line -- I make D-Jet harnesses for the T3 community -- and you're process is very similar to mine. Some of the connectors are the same, and I've toyed with L-jet type plug conversions to the T3 system so I'm sure we'd have a good conversation over beer!
so the dual cantilever contacts go in the ecu plug -- interesting. So then, what are the miniature female spades used for? I mean these:
"Digikey PN: A100770CT-ND $0.19 each. I bought 15 and had just enough after I did a few things under the dash. "
I was under the impression that the L jet harnesses moved away from these for the dual cantilever type exclusively, so I'm intrigued as to why they were kept on for some other function. _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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notchboy Samba Member
Joined: April 27, 2002 Posts: 22448 Location: Escondido CA
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Posted: Sun Sep 15, 2013 9:46 am Post subject: |
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JSMskater wrote: |
canadianveedub wrote: |
The ECU plug connectors are the ones with small square ones that look like they have 4 separate tines to them.
As to the gauge, 18 gauge is the closest to the OG wire used. It is actually slightly larger.
Waytek wire or Del City are the two best places I have found as online wiring suppliers, however, they do not usually carry the proper connectors.
Does anyone have a PN for the boots?
I am pretty passionate about fuel injection. I built my first megasquirt EFI when I was 21 and I have manufactured VW TDI performance electronics (hence my love of wiring harnesses). I know that it does not seem as simple as carbs, but once you get it running right, everything gets so easy. I honestly would rather spend a day electrically troubleshooting a no-start than doing any sort of mechanical work. |
check out my website in my sig line -- I make D-Jet harnesses for the T3 community -- and you're process is very similar to mine. Some of the connectors are the same, and I've toyed with L-jet type plug conversions to the T3 system so I'm sure we'd have a good conversation over beer!
so the dual cantilever contacts go in the ecu plug -- interesting. So then, what are the miniature female spades used for? I mean these:
"Digikey PN: A100770CT-ND $0.19 each. I bought 15 and had just enough after I did a few things under the dash. "
I was under the impression that the L jet harnesses moved away from these for the dual cantilever type exclusively, so I'm intrigued as to why they were kept on for some other function. |
Mmmm, Mongo use silly putty for windshield. No can play with sharp things.
This is the part where I stop following this chest deep, but important nerdorium thread. Skater, Im glad to have you around when I need you. _________________
t3kg wrote: |
OK, this thread is over. You win. |
Jason "notchboy" Weigel
1964 1500 S
1964 T34 S Convertible
1977 Westfalia Camper pop-top |
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geopanoramic Samba Member
Joined: September 10, 2008 Posts: 195 Location: Moscow, ID
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Posted: Sun Sep 15, 2013 12:55 pm Post subject: |
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watched a friend do that with a soob wiring harness..... Hard work! (edited - oh -I guess those pesky posts were edited out of this thread). Well eat hardy so you can think well to solve these tough fix it right problems.
Impressive recording of your work - I do want a real crimper like you suggest! |
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canadianveedub Samba Member
Joined: January 28, 2013 Posts: 40 Location: Edmonton
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Posted: Sun Sep 15, 2013 9:27 pm Post subject: |
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The Female .110" connectors are for the small double relay contacts, some of the tail lights and interior lights, several things behind the dash (like the stupid brake warning light that drives me nuts to get working)
Both of the gold coloured female receptacles have the retaining tabs on them. |
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canadianveedub Samba Member
Joined: January 28, 2013 Posts: 40 Location: Edmonton
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Posted: Sun Sep 15, 2013 9:27 pm Post subject: |
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The Female .110" connectors are for the small double relay contacts, some of the tail lights and interior lights, several things behind the dash (like the stupid brake warning light that drives me nuts to get working)
Both of the gold coloured female receptacles have the retaining tabs on them. |
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MadMax78 Samba Member
Joined: May 26, 2007 Posts: 511 Location: The Netherlands
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Posted: Tue Sep 17, 2013 7:33 am Post subject: |
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Great stuff, looks good. I'd like to add my own experience with this job, so other people may be encouraged to do this.
I used the method 77Campmobile already mentioned; the nailboard. Although I used a very crude nailboard, it's a great method. You just pin down your old wiring harness and start running wires starting at the ECU connector.
All wires replaced
When you use the wire labels, it's a good idea to use transparent shrink wrap over them, or they will come of.
Almost done! When you take your old harness apart, take a good look at how some wires are routed. Some wires make U turns in the harness.
I finished the rest of the wiring on the engine, to make sure everything is trimmed to length. As you can see in this picture, I also incorporated the wiring for the dipstick temperature sensor, the oil pressure sensor and tachometer in the wiring harness.
Happy wiring! _________________ 1978 T2b ASI Riviera Plan I // Camper Special with MegaSquirt Injection & Ignition // 091 with 5.14 R/P and Peloquins LSD
Powered by Just Kampers, German Supply , Busted Bus, Aircooled Technology & DIYAutoTune
2008: Amsterdam - Beijing - Olympics -- 17.500km
2010: Amsterdam - Cape Town - FIFA World Cup -- 26.000km
2014: New York - Rio de Janeiro - FIFA World Cup -- 27.000km
http://www.oranjetrophy.nl
******************************************
Camper Special Club Member |
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canadianveedub Samba Member
Joined: January 28, 2013 Posts: 40 Location: Edmonton
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Posted: Tue Sep 17, 2013 8:39 am Post subject: |
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Great job MadMax.
I am happy to see that others are rebuilding the wiring harnesses. I can not believe how great my bus runs with the factory EFI. It starts easy, idles high until warm and has a steady, smooth idle. It pulls great and makes no popping on deceleration. I was actually surprised at how much torque the bus has.
If I were to do it again now, I would certainly strip it down and do the shrink wrap covering. The split loom is OK, but it just doesn't have that clean look. I was pretty nervous to get everything accurate with all white wires. The problem with my method was that I had put all of the connectors on by the time I had the harness together.
Does anyone have a source for new Double Relay plugs? I have scoured the internet looking for a source of the l-jet ECU connector with no luck, unless you want to buy 100+ of them from a factory. |
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germansupplyscott Samba Member
Joined: May 22, 2004 Posts: 7093 Location: toronto
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germansupplyscott Samba Member
Joined: May 22, 2004 Posts: 7093 Location: toronto
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Posted: Tue Sep 17, 2013 9:11 am Post subject: |
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JSMskater wrote: |
So then, what are the miniature female spades used for? |
they are in the double relay terminal housings. _________________ SL |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Tue Sep 17, 2013 9:29 am Post subject: |
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germansupplyscott wrote: |
JSMskater wrote: |
So then, what are the miniature female spades used for? |
they are in the double relay terminal housings. |
thanks _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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Manfreds78bay Samba Member
Joined: February 27, 2009 Posts: 754 Location: PNW
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Posted: Tue Sep 17, 2013 1:44 pm Post subject: |
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Great Post! Can't wait to do mine. One suggestion. Put the word FI or Fuel Injection in the thread title to make it easier for people to find. When I search, I only search titles. _________________ 1978 2.0L FI Campmobile
1982 AMC Eagle SX4 4.2L FI |
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Manfreds78bay Samba Member
Joined: February 27, 2009 Posts: 754 Location: PNW
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Posted: Tue Sep 17, 2013 1:47 pm Post subject: |
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Great Post! Can't wait to do mine. _________________ 1978 2.0L FI Campmobile
1982 AMC Eagle SX4 4.2L FI |
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