Wiring - Engine Harness, Part 1 (June 7 - 18, 2013)

This post covers the modifications I made to the GMPP EFI harness, on the engine side of the firewall. Obviously the harness would have worked as delivered, but I am using the Deutsch bulkhead connectors. So I will be sectioning the harness at the firewall rather than using a large hole with a grommet to pass through the firewall. This also gives me the opportunity to tailor the length of the various wire runs. GM makes the harness to be very universal as far as component mounting, so the wires seem like you could run them from one end of the car to the other. Also the harness comes wrapped with the split convoluted tubing which is quite bulky and not too attractive. So I will be shortening, lengthening and re-wrapping to get the harness to fit tight and be as unobtrusive as possible.

After stripping the convoluted tubing from this part of the harness, this is what we have to work with. I have it loosely laid out to the various points of connection.    

   

"Unweaving" the wires....

I identified the point of the harness where the bulkhead connectors will be located. That is where I will be sectioning the harness. I marked the wires on both sides of where I will be cutting the wire.

These are the even bank injector and coil connectors separated from the harness.

This is most of the connectors for the engine.

I started on the even bank side with the ETC lead and the a/c clutch lead. Simple so far !

You can see the recesses in the firewall where the bulkhead connectors will be located.

I used adhesive lined heat shrink on all of the new connections.

Here you can see where I started the braided covering.

This is an injector plug. I added 1/8" heat shrink to each of the wires. It's a bit of protection and helps to tone down all of the colored wires. The idea is to try and make as much of the harness as possible go away to the eye.

Moved what I had done to this point out of the way to work on the coil harness. 

   

Had to lengthen some of the leads. All soldered and heat shrunk.

Even bank harness with braid applied.

Tucks in nicely between the injectors and the valve cover.

Same process for the odd bank.

Injectors

Coils

   
Both going together.

MAF and coolant temp leads. (located on the odd bank)

Odd bank wrapped and complete

Odd bank O2, knock sensor and oil pressure leads

Trans harness (includes VSS, reverse lock out solenoid and reverse light switch)

These are the lower leads coming up topside.

Even bank O2, knock and Dakota coolant temp leads

Passenger side harnesses combined. You can see the driver's side already combined and wrapped with braid.

At this point the engine harness is complete except for crimping the pins for the bulkhead connectors to the leads. I will do this when I get the cabin side of the harness complete. Wire Care rents the crimper for $25 a week. Much better than the $250 sell price!