OIl pressure ports on 4.3L

[bashr52]

This may be a dumb question, but I'm trying to sort out some wiring issues on my new boat with a 1994 4.3L. The oil/water temp warning horn is not working and I'm trying to chase down a wiring issue (new alarm, confirmed I am not getting a ground signal from the signal wire with key on engine off like I should).

I've been looking all over the block and I have found the oil pressure cutoff for the fuel pump just above the oil filter, and the oil pressure gauge sender on the rear of the block by the distributor. I have no idea where the warning horn sender is however. Can someone shed some light on this for me?

 

[Scott Danforth]

Should be one and the same for the gauge. Gauge wire will be a blue wire, don't remember the switch wire color

 

[alldodge]

All the alarm wires for your year motor are Tan/Blue. The same color goes for the lube oil bottle, water temp and oil pressure

Edit: Change that should be yellow for oil if it has TB5 if TB4 it will be the Tan/Blue

 

[Jmunk]

Mine was just to the right of the distributor when facing the front of the engine. Just replaced my pressure switch.

Pull the wire off the pressure switch and connect to ground and see if alarm sounds with key on engine off. If it does them connect the wire to the pressure switch and connect a wire to ground and to base of switch to see if it's a ground issue. If it doesn't sound when grounded replace switch.

 

[alldodge]

BTW here is the wiring diagram

 

[bashr52]

BTW here is the wiring diagram

I've found B6 and D1 in this diagram, but no pressure switch which is C1. The original engne blew 3 years ago and was replaced with a jasper rebuild of he same vintage. The oil pressure sensor for the gauge is located on the rear of the engine to the right of the dist, I'm starting to think whover did the swap may have instaled things in different locations. Where should the pressure switch for the gauge be located, maybe they got switched?

 

[alldodge]

The original engne blew 3 years ago and was replaced with a jasper rebuild of he same vintage

It could be the switch was not reinstalled. If it is a TB4 or 5 if the switch was not installed it would have no effect on operation.

There is two locations for oil pressure, below the distributer in an oil port leading from the rear cam bearing, or port side down low next to oil filter mounting

 

[NHGuy]

Also be aware if you have electric fuel pump, (I think you said you do), in that case there will be a total of three sensors. I did mine by tee'ing off the opening behind the port side head.

 

[bashr52]

Also be aware if you have electric fuel pump, (I think you said you do), in that case there will be a total of three sensors. I did mine by tee'ing off the opening behind the port side head.

That's what I'm seeing on the diagram, and makes sense. I found 2 of them, but the third one seems to be MIA. Was the factory sensor teed into the same port as the sending unit for the oil pressure gauge? Seems like something has to double up if there are only 2 ports but 3 senders.

 

[alldodge]

Seems like something has to double up if there are only 2 ports but 3 senders.

Yes they do have to double up, by using a Tee on one of the ports. Most often used is the one by the oil filter.

Just to check, do you have an electric fuel pump?

 

[bashr52]

I believe there is an electric pump, there is an oil pressure fuel pump cutoff switch installed and wired in on the block down by the oil filter.

 

[alldodge]

You should see something like this there

 

[bashr52]

Nope, nothing like that on either pressure port. I think I found my issue, nothing was ever re-installed during the engine swap... makes me wonder what else I am going to find. Where should the water temp sensor be for the alarm? I can at least get that hooked up and working until I can get the T fitting and pressure sensor for the oil.

 

[alldodge]

What temp goes up on the Thermostat housing. Should have one on each side, one temp alarm switch (Tan/Blue TB4, or Yellow TB-5), the other is the temp gauge (Tan)