Tbi to delco est wiring .

[djmakko]

87' Mercruiser 260/5.7 Alpha 1 gen 1.
Installed a New Engine that came with delco est, I have the original wire harness, I started the engine on the floor by jumping 5/6 drive current to 7 pin, started right away although I ran a separarate wire to the electric fuel pump ,
Now the engine is in place and trying to connect the electric pump which supposed to be connected with the oil sender , well the lite blue wire that goes to the oil sender only gives me 7v , not enough to run the fuel pump,

I ran the wires like I read in some posts and schematics from Don S. running a wire from the left side of the starter which supposed to be purple/ yellow ,but I don't have that wire in my harness so I ran one from there to the fuel pump then to the electric choke on the Holley 600 cfm, and then to the purple from ignition , so now my question is what do I do with the oil sender should I take another wire from the purple and connect it to it , seems like the only wire with current is the PURPLE from ignition, and also I have to take current from the Purple to the interruptor switch , wouldn't this Purple be overloaded?

 

[Bt Doctur]

Re: Tbi to delco est wiring .

You dont use the oil sender or its wiring to power up a fuel pump.you use the oil pressure switch that is connected to the oil gallery to operate a fuel pump. Once the engine has oil pressure the pump turns on.#5 is the pressure switch

 

[djmakko]

Re: Tbi to delco est wiring .

That's what I meant to say oil pressure switch but the wire that feed it a lite blue wire only gives me 7v , if I'm correct is the one that goes behind the engine next to the distributer .

 

[Bt Doctur]

Re: Tbi to delco est wiring .

light blue goes to the oil pressure sender that goes to the gauge.,
there is another called a pressure switch to operate the fuel pump.

 

[Bt Doctur]

Re: Tbi to delco est wiring .

Item #8 is the pressure switch page 4 E -2 http://www.boatfix.com/merc/Servmanl/18/18E4R2.PDF

 

[djmakko]

Re: Tbi to delco est wiring .

i dont think i have an oil pressure switch, only a oil sender switch which is # 5, where'd the pressure switch be? next to the breaker button ? looks like a solenoid ?

 

[Bt Doctur]

Re: Tbi to delco est wiring .

pressure switch iis in the hole just above the oil filter, the second area is just to the right rear of the dist in the block, this is where the oil pressure SENDER goes.Why did you replace the mechanical with electric? you need to get a pressure switch either normally open (closes with oil pressure) or a normally open /normally closed one with 3 terminals. power to conmmon, normally open to oil gallery, normally closed to solenoid

 

[Bt Doctur]

Re: Tbi to delco est wiring .

C and the hole on the flat part of the block just to the right of B

 

[djmakko]

Re: Tbi to delco est wiring .

actually the electric came with the new engine and the delco as well, according to this pic above i do have the oil pressure switch with two prongs one say ON the other one say G im assuming ground , so im going to need to install a sending unit , now how do i wire the oil pressure switch ? purple wire to ON prong and fuel pump to the same prong and what about the choke, same purple ? so should i eliminate the one i have coming from starter solenoid left side to the + on the fuel pump? i'd post some pics later today maybe that would explain a little bit better what im triyng to do.

 

[Bt Doctur]

Re: Tbi to delco est wiring .

Theres nothing to figure out, just follow the diagrams in the above post, never assume anything.purple is the main power, that goes to the switch, the other side goes to the + side of the fuel pump, the other fuel pump wire goes to ground.
The purple/yellow runs the pump only in "start" mode.Once you have oil pressure the switch closes and that runs the pump.

 

[djmakko]

Re: Tbi to delco est wiring .

Thanks Doc, became clearer now!