1975 Ford 3550 key on power

[jrsavoie]

I have a diesel 1975 Ford 3550 backhoe loader.
Model K5011F
Serial C429973
Unit 5E29B

Where is an easy place to grab 12 volt, key on power?

It looks like the key switch and most everything else is very hard to get to.

Would the neutral safety switch by the shifter be Key on power?

Any thoughts on a good place to mount a relay and toggle switch?

The toggle switch can be under the hood by the battery. If necessary.

Just looking for ideas and suggestions, before I see a better option, after the fact.

Thanks

 

[Harry in Ky]

If you're looking for light duty "key on" circuit, you could pull the instrument cluster out. Th key switch powers the cluster. Probably not much else on that tractor.

 

[jrsavoie]

If you're looking for light duty "key on" circuit, you could pull the instrument cluster out. The key switch powers the cluster. Probably not much else on that tractor.

I'll give that whirl.
Thank you

 

[Sean in PA]

The safety switch only has power when the key is in the start position. I'm not 100% sure, but if it still has the original generator and voltage regulator setup, there may be a terminal on the VR that only has 12 volts when the engine is running like maybe the Warning Light (WL) terminal, but I'm not 100% sure. What are you planning to power with it?

 

[jrsavoie]

The safety switch only has power when the key is in the start position. I'm not 100% sure, but if it still has the original generator and voltage regulator setup, there may be a terminal on the VR that only has 12 volts when the engine is running like maybe the Warning Light (WL) terminal, but I'm not 100% sure. What are you planning to power with it?

I switched to an alternator maybe 25 years ago.

A relay to run a lift pump

 

[Sean in PA]

A 3550 with a diesel engine should not need an electric lift pump. You should properly troubleshoot whatever fuel delivery issue you have rather than trying to use a band aid. What are the symptoms that make you think that you need a lift pump?

 

[jrsavoie]

A 3550 with a diesel engine should not need an electric lift pump. You should properly troubleshoot whatever fuel delivery issue you have rather than trying to use a band aid. What are the symptoms that make you think that you need a lift pump?

Neither should a Duramax, Jeep CRD or several other diesels.
From what I have seen, providing fuel to the Injection Pump has never caused an issue

But it doesn't hurt a thing. Especially in older machines.

The built in lift pump on the cav is supposed to put out the same 8-9 psi pressure. Having that amount of pressure supplied to it will save the cav pump.

I seriously doubt the 1975 lift pump on the Cav is still putting out the factory pressure.

I've noticed improved starting with the electric pump added. I have it set up with alligator clamps and a toggle switch at the moment.

I think we also had a stuck metering valve. That the constant flow of the electric pump, the higher rpm from the extra battery and booster charger helped rectify.

With the electric pump you can flow fuel through the Cav injection pump without cranking the engine. Part of the hard start issue on older machines is not having the fuel supplied at the correct pressure
A combination of just being wore out with about 10,000 hours and not spinning fast enough.

I really don't know how much the particulars to install the electric lift pump cost. As Everything is here.

2 lift pump to line adapters, 4 hose clamps, some 5/16 fuel line - rated for biodiesel and gasoline, a compression to npt to go into the filter housing, 1/4" 45°, 1/4" npt x 5/16 hose barb.
A compression to NPT fitting for the fuel line. Another 5/16 hose barb.
GM / AC Delco EP158 lift pump for a 1990's 6.5 diesel engine.

The lift pumps are on sale for about $70.

If anyone else does this. Use only an AC Delco or GM lift pump. I've never had good longevity with The aftermarket lift pumps of this style.

I'm not expected to be around all that much longer. Hopefully a few years. Hoping to avoid removing the Cav pump in my lifetime.

https://www.amazon.com/gp/aw/d/B000C9OSQG?psc=1&ref=ppx_pop_mob_b_asin_title

https://www.amazon.com/gp/aw/d/B001EIXQ6C?psc=1&ref=ppx_pop_mob_b_asin_title

 

[jrsavoie]

A 3550 with a diesel engine should not need an electric lift pump. You should properly troubleshoot whatever fuel delivery issue you have rather than trying to use a band aid. What are the symptoms that make you think that you need a lift pump?

On a related note. The return line from the side of the Cav pump to the fuel filter housing is run to a port with an out arrow.

It's been that way for at least 25 years.

The only picture I found online also had the line run to that port.

The plugged port next to it is an in port.

The difference being, the out port, that the return line currently runs to, cycles directly back to the Cav injection pump.

If I swap that line to the port on the fuel filter marked in, that fuel will go back through the filter, before returning the the Cav pump.

Unless I hear why it may be a bad idea, I intend to switch the return line to the "in"port, tlhe next time I open up the fuel system for a filter change or whatever.

it just makes more sense to me that the direction of flow match the arrow on the filter housing anyway. I can't see where it would make any difference in operation.

The line on the right is the Cav pump return line. I had switched the line to see if it made any difference in running and switched it back later.

 

[Sean in PA]

Neither should a Duramax, Jeep CRD or several other diesels.
From what I have seen, providing fuel to the Injection Pump has never caused an issue

But it doesn't hurt a thing. Especially in older machines.

The built in lift pump on the cav is supposed to put out the same 8-9 psi pressure. Having that amount of pressure supplied to it will save the cav pump.

I seriously doubt the 1975 lift pump on the Cav is still putting out the factory pressure.

I've noticed improved starting with the electric pump added. I have it set up with alligator clamps and a toggle switch at the moment.

I think we also had a stuck metering valve. That the constant flow of the electric pump, the higher rpm from the extra battery and booster charger helped rectify.

With the electric pump you can flow fuel through the Cav injection pump without cranking the engine. Part of the hard start issue on older machines is not having the fuel supplied at the correct pressure
A combination of just being wore out with about 10,000 hours and not spinning fast enough.

I really don't know how much the particulars to install the electric lift pump cost. As Everything is here.

2 lift pump to line adapters, 4 hose clamps, some 5/16 fuel line - rated for biodiesel and gasoline, a compression to npt to go into the filter housing, 1/4" 45°, 1/4" npt x 5/16 hose barb.
A compression to NPT fitting for the fuel line. Another 5/16 hose barb.
GM / AC Delco EP158 lift pump for a 1990's 6.5 diesel engine.

The lift pumps are on sale for about $70.

If anyone else does this. Use only an AC Delco or GM lift pump. I've never had good longevity with The aftermarket lift pumps of this style.

I'm not expected to be around all that much longer. Hopefully a few years. Hoping to avoid removing the Cav pump in my lifetime.

https://www.amazon.com/gp/aw/d/B000C9OSQG?psc=1&ref=ppx_pop_mob_b_asin_title

https://www.amazon.com/gp/aw/d/B001EIXQ6C?psc=1&ref=ppx_pop_mob_b_asin_title

A lift pump is not there for providing pressure. It is there for providing flow. The injection pump requires a certain amount of flow at its input to be able to produce the pressure that it uses to inject the fuel. Do you have an actual fuel delivery problem, or are you trying to solve a problem that you do not actually have?

 

[jrsavoie]

A lift pump is not there for providing pressure. It is there for providing flow. The injection pump requires a certain amount of flow at its input to be able to produce the pressure that it uses to inject the fuel. Do you have an actual fuel delivery problem, or are you trying to solve a problem that you do not actually have?

According to the Ford manual, the built in Cav lift pump is supposed to put out 8 - 9 psi.

Reminds me of those that said the exhaust and wiring on the old 6.5's was just fine because engineers designed it.

 

[jrsavoie]

A lift pump is not there for providing pressure. It is there for providing flow. The injection pump requires a certain amount of flow at its input to be able to produce the pressure that it uses to inject the fuel. Do you have an actual fuel delivery problem, or are you trying to solve a problem that you do not actually have?

According to the Ford manual, the built in Cav lift pump is supposed to put out 8 - 9 psi.

Reminds me of those that said the exhaust and wiring on the old 6.5's was just fine because engineers designed it.

And that the Jeep Liberty CRD and Duramaxs didn't benefit from a lift pump because they didn't come with one from.the factory.

 

[Destroked 450]

Are you saying the line from the side of the pump was connected to the out arrow, and the line on the back of the pump was connected to the in arrow
That would be reversed allowing unfiltered fuel into the pump, there is a small screen in the back of the pump that prevents trash from entering the transfer pump

 

[jrsavoie]

There's an out arrow and an in arrow on both sides of the pump.

3 ports are used. One is plugged.

On the left side, incoming to the tank appropriately goes to an in port.
The line going from the filter housing to the Cav pump is approximately on the out port.

On the right side the return line from the Cav pump originally went to the out port.
Which allows the recirculation of fuel back to the Cav pump without running through the filter again.

If a machine sits a while and gets some grunge going on - that stuff is going right back to the Cav pump without being filtered again.

In the picture it shows on the "in" port. Where I think it should be. I see no disadvantages to having it there.
Returning to the in port will send the fuel back through the filter again before returning to the Cav pump.

Returning fuel to the pump without running it through the filter again is one of the failings of the Ford CP4 injection pump designs

 

[Destroked 450]

After reviewing parts and service manuals plus going out to look a 3 of my 3 cylinder Fords plus one of the 4 cylinder model with CAV inj pumps I believe there is a misunderstanding
CAV pump use diesel for lubricating the governor assembly, the line going from the filter to the fitting on the outside of the pump is the supply line to governor housing for lubrication
The return is on the inside next to the block were the return line connects to the injector returns sending fuel back to the tank
No fuel is returned to the filter on this system

 

[jrsavoie]

Ok. On whatever picture I looked at, the line was identified as a return line.
I thought it was in the Ford Service manual.

I know where the return that goes to the injectors is.

Thanks for setting me straight.

I'll leave the line in.the out port.