TheSamba.com :: View topic - running a fuel injected engine outside of a bus

Mon Jul 14, 2014 2:11 pm

I just got ahold of a complete '78 fuel injected 2.0L engine, and i'm hoping to get it running outside the bus. In the past i have just bolted on some carbs to run the engine & see if it's any good, but this is all intact, and i figure it might just run like it is.

I have all the wiring hooked up except a few wires coming from the double relay. The fat red wire i'm pretty sure goes to the main hot post on the starter? I believe i have the wiring to the fuel pump hooked up right, but there are 2 black wires with plastic covers on the terminals & a yellow/orange wire that i'm no sure about. Another black wire looks like it should be hooked to the coil?

The bus i'd like to put this engine into has had the wiring cut long ago, and i just found this (double relay) wiring harness laying in a pile of wires i had laying around, so i'm hoping if i get it running i can wire this back into the bus.

I'm missing the plastic cover for my relay :cry:

The black wire needs reconnected as it was cut, but what is the yellow/red wire for?

The wires to the fuel pump have the rubber ends on them that i recognize, but what about these 2 black wire & the red on?

Not sure if the ECU needed to be grounded or not, but i figured that it is normally grounded through the mounting hardware of the body so i ran a ground to it just to be safe.

Any help would be appreciated, once i figure this stuff out i can feed it gas, and a battery, then run a few more tests on it & see if it runs.

Mon Jul 14, 2014 3:14 pm

You can run anything with a spray bottle for a while- but those lean pops can be exciting.

Mon Jul 14, 2014 3:25 pm

williamM wrote: You can run anything with a spray bottle for a while- but those lean pops can be exciting.

You would still need the double relay hooked up i'd assume. Mainly i'm just wondering which wires go where from the double relay so i don't burn anything up.

I want to be able to hear the engine run, tune it up, make it run well, then put it in my bus.

Mon Jul 14, 2014 3:29 pm

You should match up the terminal numbers with the diagram to confirm but 75/76 had a yellow wire to the spade on the starter. Red definitely goes to the battery post on the starter. The black wires could be backup lights, pics are too cryptic, I don't see the fused wire between the coil #15 and double relay either.

Mon Jul 14, 2014 4:11 pm

busdaddy wrote: You should match up the terminal numbers with the diagram to confirm but 75/76 had a yellow wire to the spade on the starter. Red definitely goes to the battery post on the starter. The black wires could be backup lights, pics are too cryptic, I don't see the fused wire between the coil #15 and double relay either.

The wiring diagram shows a picture of the double relay, but no color wires go to or from it or the yellow & red wire.

The color wire portion of the wire harness very well could have come out of a 75 bus i parted out a while back. Those black wires look like a reverse light setup now that you mention it. Do they typically run the reverse light harness through the double relay harness?

Mon Jul 14, 2014 5:04 pm

But you know what terminal the colored wire is on so look at the relay in the diagram (it's J40, the pic of the relay below it is just to show you what area the diagram is discussing) and see where the wire attached to that terminal goes. The 76 diagram has legible terminal numbers and will work for your purposes.

Mon Jul 14, 2014 6:26 pm

All the info you need is right here on current tracks #73-78. The wires are colored to make life easy, there are only four of them.

Red is of course the B+ circuit on the battery

86c is the #15 ignition circuit from the ignition switch via the coil.

86a is the #50 starter circuit off of the solenoid.

88d feeds the fuel pump

Double click to enlarge

Your colors don't seem to match the diagram so use the numbers on the relay instead.