Two prong oil pressure sensor

[78Delta88]

The one relay is for fuel pump, the other turns on alternator and electric choke. I'll tie into existing GM wire to power the pump. Not shown is the diode that will be hooked in as well.

I might end up modifying how I turn pump on but for now I want to try the lamp test position to prime and then start like normal. Once the oil pressure switch closes the pump will run until engine shut down. I 'll have the diode in there just as a safety to block any back feed.

This will be first time on street car using electric pump. All the other conversions I did, I just used the mechanical pump. Only exception was 65 Mustang where I used electric pump and converted its alternator to GM style and Ford electronic ignition from a 1978 302.

 

[Baker7888]

The one..

Ok after today I am pretty close to dropping a battery in so I played around with the wiring for a minute. Let me know what you think.

The factory switch connector has a brown, light blue, and pink (?) wire going to a two prong switch. I cut open the connector to find the blue and pink wires are spliced together.

I get conductivity from the blue wire to the choke wire, so blue is choke. I am *guessing* the pink wire goes to the choke light. And i am getting conductivity from the brown wire to ground, so brown is ground. The switch seems to be OPEN when engine is off.

SO — it looks to me like this switch tries to choke the carb and toggle a dash light. Basically useless for my needs. Looks like I can ditch this switch and wiring (possibly ground out pink) remove the switch, replace with Holley switch which I have on hand and follow their directions going forward.

Now one question I have is I want to run a wye here and install a sensor for electric oil pressure gauge. My three gauge set came with a mechanical which I think I do not like the idea of having oil running into the cab. Will an electric-driven gauge come with a sensor or do I need a separate sensor?

 

[78Delta88]

Ok after today I am pretty close to dropping a battery in so I played around with the wiring for a minute. Let me know what you think.

The factory switch connector has a brown, light blue, and pink (?) wire going to a two prong switch. I cut open the connector to find the blue and pink wires are spliced together.

I get conductivity from the blue wire to the choke wire, so blue is choke. I am *guessing* the pink wire goes to the choke light. And i am getting conductivity from the brown wire to ground, so brown is ground. The switch seems to be OPEN when engine is off.

SO — it looks to me like this switch tries to choke the carb and toggle a dash light. Basically useless for my needs. Looks like I can ditch this switch and wiring (possibly ground out pink) remove the switch, replace with Holley switch which I have on hand and follow their directions going forward.

Now one question I have is I want to run a wye here and install a sensor for electric oil pressure gauge. My three gauge set came with a mechanical which I think I do not like the idea of having oil running into the cab. Will an electric-driven gauge come with a sensor or do I need a separate sensor?

Hmmm??? Pink used to be to distributor ign. Looks like when oil pressure is present choke is energized, seems to be overkill for a choke.

Pretty much in a GM any thing solid red is 12 vdc hot, any thing Orange is hot @ KOEO (Key On Engine On). So at least from there you can wire your Holley switch the way they show and be done with it.

On the Electric OP gauge, probably at this point just get a new fresh one, will come as a kit, and they are fairly accurate and you done have live oil routed to back of dash.

I like the mechanical OP & Temp, but on the last few show cars I hooked them up under the hood on firewall or fender. The last El Camino I did, the customer wanted the digital dash unit. We did an HVAC delete so I made aluminum plate cover and put gauges and remote start in that so when at shows with hood open we had; vac, volts, temp and OP, plus ability to shut down and start.

 

[Baker7888]

Hmmm???

Thank you. Moving on to water, I have a sensor in the water pump, and a sensor in DS head. Which one should i use for temp gauge, and which one for fans, or does it even matter? I guess I am asking what the factory usually does

 

[Baker7888]

Could someone take a look at the attached image and tell me if this is right?

- Does "key on" mean Hot when running or hot with key forward? (I do see that it is not accessory)

-By starter circuit I am guessing they mean the small terminal?

 

[78Delta88]

Thats the way I take it, but I'm not too hip on their drawing.

It looks like they combined 2 functions into 1 wire for simplicity. Unfortunately they just made it confusing.

I looks like the 12vdc goes through the NC side, engine starts and produces oil pressure. The oil pressure opens the NC side and at the same time closes the Normally Open (NO) side. Works like a basic flip/flop switch.

I guess, wire as they show and see how it works. Get ready to disconnect Batt ground if engine doesn't shut off.

 

[78Delta88]

Moving on to water... The one in the head is more likely a switch, as the flow coming from the head will be the hottest. The flow from the head goes into the cross over where it exits through the thermostat.

Not knowing exactly where the one is in the water pump, not sure... The coolant in water pump should be cooler, as it was coming from the radiator and had some of its heat removed.

 

[78Delta88]

Ok ... Might be backwards on this, just looked up your previous post, you have the LT1 which has reverse cooling.

Do you know year and make/model of the donor car that the LT1 came from?

 

[78Delta88]

Attached link from Firebird site, goes over issues with cooling on LTI.

The one in the head communicates with the gauge.

The one in the water pump communicates with the ECM.

https://www.firebirdnation.com/d3/pdf/coolingsensors.pdf