3.5 efi bench test help

[dandsas]

hi im a complete newbie and i want to bench test the engine before fitting it see if its ok
and i need to know how to wire it i have 2 red/white wires and 2 white 1 brown and 1 purple and white
its a 2 wire dizzy and a blue and white wire which i take goes to the coil for the ecu
sorry its so vaque

[dandsas]

right ive got it turning over a good spark petrol but nothing in the barrels does the ecu need earthing?

[ramon alban]

hi im a complete newbie and i want to bench test the engine before fitting it see if its ok
and i need to know how to wire it i have 2 red/white wires and 2 white 1 brown and 1 purple and white
its a 2 wire dizzy and a blue and white wire which i take goes to the coil for the ecu
sorry its so vaque

Vague? Not to the clairvoyants who infest this forum! So here goes!

I'm assuming your efi wiring loom and ECU and the main relay, fuel pump relay and the diode steering module, AFM and all sensors are connected and what you describe are the left overs.

The two white wires go to the ign switch and positive side of the coil.

The brown wire goes to the battery + and ign switch.

The purple and white (which is actually white and purple) wire goes to the fuel pump via the fuel pump resistor.

One of the red white wires goes to the ign switch cranking terminal, the other is a mystery but I suspect the two wires are to be joined and go to the same place.

There aint no blue white wire that makes sense because it is part of the AFM circuit but you are missing a white black wire that goes to the ECU via the 6.8kohm trigger resistor. Could that be the one you describe?

I got all this info from the temporary cct diagram available here:

http://www.vintagemodelairplane.com/pag ... uit01.html

If you search all the "Download" and "Efi Component" archives on my website you will find other stuff which may be of assistance.

I have led a sheltered life and you are the first home mechanic/owner I have ever heard of, try and bench test an Efi system, so I am reminded of the time when I was lost in Dublin and asked a local cabbie for directions.

The answer came back, "If I were you Sir, I wouldn't start from here!"

Good luck.

[Slothie]

Totally offtopic, Ramon, but I'd like to thank you for the stuff on your site, it's helped me out no end getting to grips with my V8, and is an interesting read.

[dandsas]

hi
right ive traced my pin 1 white and black wire it goes to a relay with a white wire and a black wire then theres a short blue and white wire coming from the relay with a female spade connector

[ChrisJC]

I think that wire goes to coil -ve, but check a wiring diagram first!!

Chris.

[ramon alban]

hi
right ive traced my pin 1 white and black wire it goes to a relay with a white wire and a black wire then theres a short blue and white wire coming from the relay with a female spade connector

Chris is right, but that relay would not be on any circuit diagram that I may have referred you to because it is prolly part of a later RR overrun circuit operated by a vacuum switch, not seen on SD1.

Alternatively it could be a retro-fitted inhibiting circuit.

[dandsas]

hi
do i still need the 510ohm resistor on this wire which i dont have but ive made one in case if that works the same and what resistor do i need on the fuel pump??
thanks for your help

[dandsas]

hi
guys its now sorted and running
the reason i wanted to bench test the engine is because its the first engine ive ever built and wasnt holding much hope out for it so i didnt want to put it in my custom project if it didnt run

[ramon alban]

I think you did damn well. Hope the project continues the same way.

[Slothie]

hi
guys its now sorted and running
the reason i wanted to bench test the engine is because its the first engine ive ever built and wasnt holding much hope out for it so i didnt want to put it in my custom project if it didnt run

Perhaps if you get time, you could do a diagram showing what you did - I'm sure a "minimal wiring" diagram showing the connections you had to made would be a lot of use to people on this forum.

Well done!

[ramon alban]

Perhaps if you get time, you could do a diagram showing what you did - I'm sure a "minimal wiring" diagram showing the connections you had to made would be a lot of use to people on this forum.

Well done!

Slothie, I dont think there is a minimal situation. Most of the Efi components have to be in place except perhaps cold start cct.

So the diagram has to be as shown in temporary cct diagram available here:

http://www.vintagemodelairplane.com/pag ... uit01.html

[Slothie]

Slothie, I dont think there is a minimal situation. Most of the Efi components have to be in place except perhaps cold start cct.

I was sort of working from the point you mentioned of having the efi loom and components connected, and needing to connect up the remaining wires (I was assuming that there is a seperate loom for the engine - like the old efi V6 ford I used to have had a completely seperate loom for the engine sensors/ECU that plugged into the rest of the car with a multi-connector).

[ramon alban]

I was assuming that there is a seperate loom for the engine - like the old efi V6 ford I used to have had a completely seperate loom for the engine sensors/ECU that plugged into the rest of the car with a multi-connector.

The SD1 Efi Loom seems uniquely to have flying leads terminating with spades or similar to go off to the points in the original query.

There would be the other engine loom that serves the starter cct and some more sensors etc.

The trouble with any off car test bed might depend upon what came with the original set-up and what vehicle it came from.