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delete computer on a 1986
https://slantsix.org/forum/viewtopic.php?t=54121		 Page 1 of 2
Author:  cseby [ Sat Dec 21, 2013 7:25 pm ]
Post subject:  delete computer on a 1986
i'm new to the forum today.help me out. I bought a 1986 d100 with automatic transmission.i would like to delete the computer on this truck.does the computer only control three things,the distributor,the carbruator and the lock up torque converter? am I right by saying I need to change the carburetor so I have vacuum for the advance on the distrubutor?what are my best options for a distributor and carburetor? thank you for your help.
Author:  Ed Mullen [ Mon Dec 23, 2013 9:05 am ]
Post subject: 
Also EGR and smog pump diverter.

Does not neccesarily control carb. (Holley 6145: yes, 1945: no)

Any 70's 1945 should work, as long as it has ported vacuum for distributor. (often labeled "OSAC").

Later 1920's as well, but 1945 parts way more abundant right now.

Distributor choices depend on whether you want points or EI/HEI.
Author:  Reed [ Mon Dec 23, 2013 10:39 am ]
Post subject: 
It is exceedingly unlikely that the computer controls the lockup torque converter. If your truck was sold in the California market it may not even have a lockup torque converter.
Author:  cseby [ Mon Dec 23, 2013 3:32 pm ]
Post subject: 
thanks for the replys.your input is a big help.any other thoughts on this computer delete would be a great help.the truck is on it's way home to pa. from out west ,so I have not seen it yet.just trying to get my ducks in a line so I can change a few things when it arrives. I guess i'm to old,but I like as much mechanical as possible.just not computer orientated.thanks for the carburetor suggestions.after reading many posts I think the hei ignition is the way to go.what distrubiator is my best choice?i went to a local dealer and asked for a "vehicle information report" and found out it has a lock up converter.report says it has a HD A904 with lock-up converter. I forgot the older lock ups were not electrically controlled.
Author:  /'d Box [ Mon Dec 23, 2013 3:58 pm ]
Post subject: 
My 85 van was converted many years ago with a kit that was available from mopar. I think the kit came with a distributor, orange brain box, a harness that had to be tapped into the factory harness and instructions. The computer just gets unplugged and maybe a few wires snipped. If you're starting fresh with no parts, I would recommend reading up the HEI discussions.
So, you'll need a carb, dist., and your choice of ignition.
If I were doing this conversion today, I'd go with a modern HEI and build a dedicated harness for it. Tapping into a 23 yr old harness can get messy and have reliability issues. Ask me how I know. :roll:
Author:  cseby [ Mon Dec 23, 2013 4:09 pm ]
Post subject: 
this seems like a fairly easy job thanks to your help and parts suggestions.can I make up a hand choke for the 1945 and the 1920 carburators? also I don't mind making up a wiring harness for the distrubiator.
Author:  xjarhead [ Wed Dec 25, 2013 7:44 am ]
Post subject: 
I have done this on my 86, manual trans.
I gutted the computer.
The housing is 2 pieces pull all the screws, pull all the electronics out and the vacuum canister.
Then you are left with and nice 4"x6" area to fit a piece of 1/4" aluminum(heat sink for mounting HEI module).
All the wires to wire the HEI module were plugged into the computer so no need to run new wires, unless yours are in bad shape mine were fine.
There are 2 wires that run to the coil, 2 that run to distributor and a ground wire. Have to have ground wire to ground the HEI module.
So mount the HEI to the heat sink, dont forget the dielectric grease.
Make sure module fits flat against the heat sink, mine had pins i had to grind down.
Then connect the ground to 1 of the 2 screws that you mounted the HEI with.
Then run a length of wire from each terminal of the HEI out 1 of the holes in the computer housing where the original wires plugged in.
I just went to the junk yard to find a 6 pin weather pack connector to connect the original 5 wires to the one's extending from the HEI module.
That way i would have a way to disconnect the computer housing from the harness if i ever had to change the module.
Don't buy this connector at NAPA its to expensive, just get new pins and seal's there.
There is no ballast resistor to take out.
The reason i mounted mine in the computer housing is that there is a small diameter hose that runs from the air intake for the engine to the computer housing.
Its there to help draw air thru the computer housing to keep the electronics cool.
Then install a electronic distributor with vacuum advance on it, and a carb.
I have Holley 1920 on mine.
Good luck any questions just ask.

P.S. you should have about 15 wire's that you can eliminate from your harness.

Dave
Author:  xjarhead [ Wed Dec 25, 2013 7:55 am ]
Post subject: 
Quote:
this seems like a fairly easy job thanks to your help and parts suggestions.can I make up a hand choke for the 1945 and the 1920 carburators? also I don't mind making up a wiring harness for the distrubiator.
No need for hand choke.
Call Carbs Only and tell them what you have and they can get you correct electric choke. http://www.slantsix.org/forum/viewtopic.php?t=12996

Dave
Author:  65 dartman [ Wed Dec 25, 2013 5:53 pm ]
Post subject: 
Quote:
I have done this on my 86, manual trans.
I gutted the computer.
The housing is 2 pieces pull all the screws, pull all the electronics out and the vacuum canister.
Then you are left with and nice 4"x6" area to fit a piece of 1/4" aluminum(heat sink for mounting HEI module).
All the wires to wire the HEI module were plugged into the computer so no need to run new wires, unless yours are in bad shape mine were fine.
There are 2 wires that run to the coil, 2 that run to distributor and a ground wire. Have to have ground wire to ground the HEI module.
So mount the HEI to the heat sink, dont forget the dielectric grease.
Make sure module fits flat against the heat sink, mine had pins i had to grind down.
Then connect the ground to 1 of the 2 screws that you mounted the HEI with.
Then run a length of wire from each terminal of the HEI out 1 of the holes in the computer housing where the original wires plugged in.
I just went to the junk yard to find a 6 pin weather pack connector to connect the original 5 wires to the one's extending from the HEI module.
That way i would have a way to disconnect the computer housing from the harness if i ever had to change the module.
Don't buy this connector at NAPA its to expensive, just get new pins and seal's there.
There is no ballast resistor to take out.
The reason i mounted mine in the computer housing is that there is a small diameter hose that runs from the air intake for the engine to the computer housing.
Its there to help draw air thru the computer housing to keep the electronics cool.
Then install a electronic distributor with vacuum advance on it, and a carb.
I have Holley 1920 on mine.
Good luck any questions just ask.

P.S. you should have about 15 wire's that you can eliminate from your harness.

Dave
This sounds like a great plan to do the same thing on my 87 D100 slant.
Author:  xjarhead [ Wed Dec 25, 2013 9:41 pm ]
Post subject: 
Quote:
Quote:
I have done this on my 86, manual trans.
I gutted the computer.
The housing is 2 pieces pull all the screws, pull all the electronics out and the vacuum canister.
Then you are left with and nice 4"x6" area to fit a piece of 1/4" aluminum(heat sink for mounting HEI module).
All the wires to wire the HEI module were plugged into the computer so no need to run new wires, unless yours are in bad shape mine were fine.
There are 2 wires that run to the coil, 2 that run to distributor and a ground wire. Have to have ground wire to ground the HEI module.
So mount the HEI to the heat sink, dont forget the dielectric grease.
Make sure module fits flat against the heat sink, mine had pins i had to grind down.
Then connect the ground to 1 of the 2 screws that you mounted the HEI with.
Then run a length of wire from each terminal of the HEI out 1 of the holes in the computer housing where the original wires plugged in.
I just went to the junk yard to find a 6 pin weather pack connector to connect the original 5 wires to the one's extending from the HEI module.
That way i would have a way to disconnect the computer housing from the harness if i ever had to change the module.
Don't buy this connector at NAPA its to expensive, just get new pins and seal's there.
There is no ballast resistor to take out.
The reason i mounted mine in the computer housing is that there is a small diameter hose that runs from the air intake for the engine to the computer housing.
Its there to help draw air thru the computer housing to keep the electronics cool.
Then install a electronic distributor with vacuum advance on it, and a carb.
I have Holley 1920 on mine.
Good luck any questions just ask.

P.S. you should have about 15 wire's that you can eliminate from your harness.

Dave
This sounds like a great plan to do the same thing on my 87 D100 slant.
I dont miss that computer at all.
It's without a doubt the best thing you can do, going with the HEI.
If you have any questions let me know.
I may still have the the schematics from the service manual showing which wires to use for this.

Dave
Author:  cseby [ Thu Dec 26, 2013 4:41 am ]
Post subject: 
dave,thanks for the great post.i think I will do what you did.sounds very neat any tidy.two questions. does the computer control anything other than ignition spark on my 1986 d100? also on your signature what does the #55 after the 1920 indicate?
Author:  Ssg Pohlman [ Thu Dec 26, 2013 7:44 am ]
Post subject: 
The "#55 I'm betting is his jet size in his holley.

I will add too that deleting the lean burn and going HEI was one of the biggest improvements I done when I first got mine. I was having issues thinking it was a carb issue but turned out to be the lean burn/dizzy, etc.

Recommend to read up on the HEI thread, compile your parts, and take your time. I done the swap in the bay of a car wash in VA :shock: didn't even swap the dizzy at the time but still ran great.

Not sure about PA but if you can get rid of that CAT just after the manifold. If you can't get rid of the old cats just get some free flowing ones. As most do, go w 2 1/4". The cat on mine was plugged bad. There's another member w a red step side that took pics of his. He will bout for the change.

There's a few pics of my install in the slixer gallery and of course a lot in the HEI thread.

Keep us posted how it works out. And don't throw away parts as others may want them for whatever reason.
Author:  xjarhead [ Thu Dec 26, 2013 10:30 am ]
Post subject: 
Author:  Reed [ Thu Dec 26, 2013 2:16 pm ]
Post subject: 
There have been reports that some 1987 trucks and vans had a lockup torque converter controlled by the lean burn computer. I have never seen this verified, so i don;t know if it is true. However, I do know that at least in 1986 slant powered trucks and vans sold in the California market had non-lockup 904s. I used to own an 86 van built that way.
Author:  65 dartman [ Thu Dec 26, 2013 5:26 pm ]
Post subject: 
Quote:

I may still have the the schematics from the service manual showing which wires to use for this.

Dave
I have the 87 FSM and looked through it this evening at the wiring diagrams. Looks like a lot of wiring (and some components) would be eliminated and even removed from the harness(es) and the remainder of the harness re-wrapped.
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