1987 V10 with carb and dual tanks will not stay running

[Sad Sack]

TBI pumps unregulated would put out over 20 psi probably in the vicinity of 35psi. Definitely more than carbs can handle. I am assuming someone has installed a bypass regulator,or made a bypass.

@Ricko1966
Which was why I was asking, more info required. I was thinking...wait a sec...

 

[Shoote]

My tan/white wire comes out of the fuse box through the firewall and to the fuel pump relay. It has power. I have a single brown wire that goes to the oil pressure sending unit. I am not sure how to combine these two wires. I am using a HEI distributor that has a tach wire. I added a tachometer when the engine was installed.

 

[Shoote]

I have a fuel pressure regulator to keep the fuel pressure about 6 psi.

Where would I tap into the tan/white wire to add it to the oil pressure sending unit? We did not do that when we installed the engine and the current single wire to the oil sending unit is a brown single wire, not orange. Oil pressure guage works.

 

[Ricko1966]

My tan/white wire comes out of the fuse box through the firewall and to the fuel pump relay. It has power. I have a single brown wire that goes to the oil pressure sending unit. I am not sure how to combine these two wires. I am using a HEI distributor that has a tach wire. I added a tachometer when the engine was installed.

You are not looking at the right wires you need 2 oil pump switches 1 for your light or gauge. 1 for fuel pump power. Easy way buy a normally open ,most oil pressure switches are normally closed. Anyway normally open 2 prong. 1 prong to power 1 prong to the fuel pump wire. Originally a TBI truck had 2 oil pressure switches just for this reason or an oil pressure switch that had 3 wires 1 for light,2 for fuel pump IDK why your truck quit running,do scour the block for a second OP switch that went bad or got disconnected. On a small block it's on the drivers side low. On a 454 TBI Idk

 

[Ricko1966]

My tan/white wire comes out of the fuse box through the firewall and to the fuel pump relay. It has power. I have a single brown wire that goes to the oil pressure sending unit. I am not sure how to combine these two wires. I am using a HEI distributor that has a tach wire. I added a tachometer when the engine was installed.

Your tach wire instance is irrelevant. The ECM needs a tach signal that it would have got from ICM in a TBI distributor.

 

[Shoote]

Can I replace the current one wire oil pressure sending unit with the two wire "open" switch if I tap into the tan/white wire and attach it to the new oil.pressure sending unit?
I do not see a second oil pressure switch on the original engine. I have the original 350 tbi on an engine stand. The one wire oil pressure sending unit is on the back of the original 350 tbi engine drivers side. Where is the second one?

Thank you for your patience and walking me through this. I am not far from having a square body bon fire!!

 

[Ricko1966]

Should be a three wire switch behind d the distributor or a 1 wire switch behind the distributor and another switch that looks like 1 of these 2 above the oil filter. Try to find an unused connector that has an orange and a tan/white wire,short it with a fused jumper lead,look at the picture. If you can't findvthe connector see if there is an orange and a tan white at the fuel pump relay,if so unplug the relay and jumper the orange to the tan/white at the relay socket. Post back.

 

[SquareRoot]

Are both your tanks running on the same relay?

If that's the case, I would swap that relay with another from the fuse box.

If its the same relay for both tanks, then its possible that it could account for this, if the relay is overheating when in use.



Long shot, but its something to explore.

You obviously don't know how a relay works.

 

[Ricko1966]

Search real hard,especially around the power steering you power washed,make sure you didn't just blow some wires or a connector off of an oil pressure switch on the block

 

[AuroraGirl]

You must be registered for see images attach

 

[Shoote]

Now I understand what you were telling me. I took a picture of the oil sending unit on the original 350 and I found the plug that went into it behind the distributor. On the Blueprint engine there is no place to install another oil sending unit. If I jump the tan/white and orange wires on the plug that went into the original oil pressure sending unit the truck should run right?
Can I buy an oil pressure sending unit that has three connections, one for the guage, one for the orange wire and one for the tan/white wire and install it on the block above the oil filter?
Thank you all again for walking me through this.

 

[AuroraGirl]

12550760 or 12596339 for the adapter to use the area by the oil filter

19244500 does fuel pump and gauge, but i dont know if the PSI matches the square body era. youd need one from the early gmt400 which i dont know where to find

 

[Ricko1966]

Just buy a tee from the hardware store and run both switches.1/8 npt TEE fitting.ps126 will work as a switch.I know another way. Busy BIAB

 

[Ricko1966]

Now I understand what you were telling me. I took a picture of the oil sending unit on the original 350 and I found the plug that went into it behind the distributor. On the Blueprint engine there is no place to install another oil sending unit. If I jump the tan/white and orange wires on the plug that went into the original oil pressure sending unit the truck should run right?
Can I buy an oil pressure sending unit that has three connections, one for the guage, one for the orange wire and one for the tan/white wire and install it on the block above the oil filter?
Thank you all again for walking me through this.

Okay now I'm home can read better and look at your pics. Did you see how I showed you to make a fused jumper? Plug your fuel pump relay back in like it was. Find the connector for the TBI fuel pump oil pressure switch. Jumper that connector with a fused jumper just twist the ends of the wires together and push them into the connector. Does the truck run now? If so pull the jumper out,unscrew the elbow and oil pressure switch out of the TBI engine. Go to the hardware store And buy a tee to replace that elbow. Put both switches on the block hook them both up. Problem should be solved.

 

[Grit dog]

I have a fuel pressure regulator to keep the fuel pressure about 6 psi.

Where would I tap into the tan/white wire to add it to the oil pressure sending unit? We did not do that when we installed the engine and the current single wire to the oil sending unit is a brown single wire, not orange. Oil pressure guage works.

I don’t know nuthin about that but dang that’s clean looking under the hood!