[Gmecm] TBI Swap - Iron Duke Tech IV

[Aphelion79]

Hey thats the kind of info I was looking for, thanks a bunch!

I'll probably work on that this comming Wednesday (whipping the harness 
into shape and seeing what goes where)...  so stay tuned for any further 
questions about that.

For now though, I am confused about one thing... which is the Fuel System:
I know I need an electric pump for this setup... but how does the fuel 
flow?   Do I need to run a new line for fuel return?  (does it just flow 
past the Throttle Body and back into the tank, and the TB just uses what 
it needs in the middle?)  Just started thinking about this recently, 
lol...  Which would mean on a carburated engine the bowl is filled just 
as quickly as the RPMs are turning the mechanical fuel pump, right? 
(thus it never overflows)



Jay Vessels wrote:

> Hi there!
>
>>    The actuall installation of the manifold/TBI is nothing for me to 
>> do... its all the wiring!  I took all the wiring that was attached to 
>> the two plugs on the ECM (which is a 1227748).  I noticed that the 
>> ECM controls the Transmission in the Oldsmobile, which I have cut off 
>> from the harness... also the electic fan wiring has been cut off...
>
>
> I would have kept the fan wiring in case the move to an electric fan 
> was ever planned.  It's easy enough to add back in later, I guess.  
> Electric fans can help pick up a bit of power versus a clutch fan.
>
>>    So, can I just cut and cap off the wires that I don't need?
>
>
> Yes.  Make sure they don't have any opportunity to short against 
> something and you'll be fine.  If there are wires going to the ECM 
> that I don't intend to use, I remove the pin from the connector -- no 
> wire, no chance of a short.  Removing pins from the ECM connector 
> shell isn't difficult.  The pins have a tab that sticks up and bites 
> into the shell.  Use a paperclip or something similar (thin 
> screwdrivers work well) to push the tab down, and pull the pin/wire out.
>
> For your setup, the transmission wiring is only controlling the lockup 
> torque converter, so as long as you don't need the ECM to run the 
> torque converter, it's okay to remove it.
>
> Do you have a wiring diagram for the Olds?  If not, try your local 
> library and see if they have any service manuals.  Or, go to a local 
> GM dealer -- many will let you photocopy pages from their shop 
> manuals. I've done this before and I've never had a dealership refuse 
> (and many have copied a page or two for me for free).  That will be a 
> great help getting the harness in shape.
>
>> Tell me whatever you all know, even if it sounds stupid, lol... what 
>> parts I need etc, and I'll make sure I've got everything squared away 
>> before I undertake this!  (BTW, I'm hoping to do this in about 2-3 
>> weeks, and will attempt to complete the entire swap within a week... 
>> Like I said, once I plug everything in and plug it into the ECM the 
>> thing will run flawlessly being the same engine, I'm just scared it 
>> wont, lol)
>
>
> I assume you still have the harness out of the vehicle -- that is, you 
> haven't installed it yet.  Lay the harness out on the floor, and 
> carefully remove all the wire loom and tape from the harness.  Clean 
> it up, rebundle it, and go over each wire and connector with the 
> wiring diagram and an ohmmeter.  As you go over it, check each 
> connector to make sure that it's in good shape, and that the ohmmeter 
> tells you that it is connected where you think it is.  This is also an 
> opportunity to re-lace the harness and arrange it so it looks and fits 
> better on your vehicle.  As you get to each connector, figure out what 
> that connector plugs into, what that component does, and why you need 
> it.  This study can come from any number of good books (i.e. the Helm 
> manual for the donor car or one of many books on EFI), the Web, or here.
>
> This will make your conversion take longer, so why do this?  Three 
> reasons.  First, it will give you confidence that the harness is in 
> good shape and that if you run into problems, it's not a fault lying 
> inside the harness.  Second, if you do find a problem in the harness 
> (i.e. bad spot in a wire) you can fix it while it's off the vehicle.  
> Third, it will give you a better understanding of the harness's layout 
> and how all the pieces are connected.  This basic understanding will 
> go a long way to understanding how a computer can run the engine, and 
> what to do if you have a problem with the installation.
>
> Jay Vessels
> 1982 Chevrolet S-10 Sport, 2.8V6 TBI
> 1984 Chevrolet S-10 Blazer Sport, 2.8V6 (TBI pending)
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