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GypsyR · 06-15-2020, 10:01 PM

All the inertia switch does is connect those two wires until it is upset and then it breaks the connection. So bypassing it gave you power up to that point for sure. Until you get your issue sorted out you might just leave them connected there.

Qstaar17 · 06-15-2020, 11:28 PM

Quote:

Originally Posted by subford

What red wire?
Do you mean the pink wire with a black stripe?

Are you using a loading test light (non LED)?

If the loading test light lights up on the dark green wire with a yellow strip going to the Inertia switch and does not light up on the pink wire with a black stripe from the Inertia switch with pin #6 grounded and the key on then you have a bad connector at the Inertia switch.

Ok so I hooked up the new connector and same thing. I figured out what I was doing wrong. I was using a T pin and reading the connector, disconnected. With the connector connected to the inertia switch, #6 of EEC grounded, key to on, I’m able to get readings from both wires of around 10volts and of course the test light lights up. So on to the next plug. I did splice to pink and green wires together to see if she would start but no luck there.

Qstaar17 · 06-16-2020, 02:18 AM

Quote:

Originally Posted by GypsyR

All the inertia switch does is connect those two wires until it is upset and then it breaks the connection. So bypassing it gave you power up to that point for sure. Until you get your issue sorted out you might just leave them connected there.

Thanks. It's looking more and more like a bad fuel pump. Just isolating as much as possible before I drop that tank.

Qstaar17 · 06-16-2020, 02:27 AM

Ok so I hooked up the new connector and same thing. I figured out what I was doing wrong. I was using a T pin and reading the connector disconnected from the inertia switch. With the connector connected to the inertia switch and #6 of EEC grounded, key to on, I’m able to get readings from both pink and green wires of around 10volts and of course the test light lights up. So on to the next plug. I did splice to pink and green wires together to see if she would start but no luck there. Next I'll read C219. It's beginning to look like I will have to drop that tank. I just want to be sure first.

theoldwizard · 06-16-2020, 04:13 AM

Quote:

Originally Posted by Qstaar17

I been searching on google and I see that the green wire goes to the fuel pump relay and the pink wire goes directly to the fuel pump.

If you have confirmed that the inertia switch is not the problem, it is time to check the fuel pump relay. The quickest way to check this is remove the relay and temporarily use another know good relay of the same style (not engine related, so lights, horn, etc) as a substitute. Have an assistant remove the fuel filler cap and place their ear close to the hole. A simple KEY ON should cause the fuel pump to run for 5 to 10 second and that can be clearly heard through the gasoline filler hole.

If that test fails, thing get a bit trickier. Do NOT swap back the substitute relay. We need to test the wiring to and from the relay socket. 2 pins go to the "control" side (the pins are sometimes imprinted on the top of the relay; the control side shows a coil of wire). One of these 2 pins goes to KEY POWER (hot when key in RUN). Use your test light from a known good ground to that contact in the fuse box to confirm this.

The other pin goes to the EEC and is grounded when it want the pump on. Connect your test light directly to battery positive and then to this second contact. Have an assistant turn the key to start. The test light should come on for about 5 to 10 seconds.

The other two pins are what actually powers the fuel pump. Repeat the above two tests on these contacts. One should be hot during KEY POWER. The other supplies current to the actual fuel pump. On this last contact, with the test light hooked to battery positive, the light should come. The pump itself is the ground. The light should come, but the pump will not start because the test light is limiting the current.

If all that passes, the last test is the following. Crawl underneath and use a rubber mallet, give the fuel tank a few good whacks in a couple different places. If there is a bad spot on the fuel pump motor winding this should jog it off of that spot and the fuel pump will run.

subford · 06-16-2020, 06:22 AM

Quote:

Originally Posted by Qstaar17

Next I'll read C219.

C219 is located at the LH frame rail (drivers side), near the transmission. It is a two Terminal connector.

Note in the location diagrams C219 & C218 are sometimes miss labeled and locations reversed.
So go by the wire colors for these two connectors.

/

Qstaar17 · 06-16-2020, 11:11 PM

My plan is to trace power all the way to the pump and if the pump is receiving power, drop tank and replace the pump. I see that Auto Zone has it for 400 bucks. Things I've done so far. Verified that all fuses in the distribution box are good, verified that all relays are good, swapped relays, verified chassis battery output, cleaned battery terminals, replaced solenoid switch, verified that inertia switch was not triggered, replaced the inertia switch, replaced inertia switch connector, conducted fuel pressure test and got zero fuel pressure, replaced the fuel filter and replaced the fuel pressure regulator. At this rate I'll have a new RV, lol.

Qstaar17 · 06-16-2020, 11:13 PM

Thanks. My plan is to trace power all the way to the pump and if the pump is receiving power, drop tank and replace the pump. I see that Auto Zone has it for 400 bucks. Things I've done so far. Verified that all fuses in the distribution box are good, verified that all relays are good, swapped relays, verified chassis battery output, cleaned battery terminals, replaced solenoid switch, verified that inertia switch was not triggered, replaced the inertia switch, replaced inertia switch connector, conducted fuel pressure test and got zero fuel pressure, replaced the fuel filter and replaced the fuel pressure regulator. At this rate I'll have a new RV, lol.

Qstaar17 · 06-16-2020, 11:23 PM

Quote:

Originally Posted by theoldwizard

If you have confirmed that the inertia switch is not the problem, it is time to check the fuel pump relay. The quickest way to check this is remove the relay and temporarily use another know good relay of the same style (not engine related, so lights, horn, etc) as a substitute. Have an assistant remove the fuel filler cap and place their ear close to the hole. A simple KEY ON should cause the fuel pump to run for 5 to 10 second and that can be clearly heard through the gasoline filler hole.

If that test fails, thing get a bit trickier. Do NOT swap back the substitute relay. We need to test the wiring to and from the relay socket. 2 pins go to the "control" side (the pins are sometimes imprinted on the top of the relay; the control side shows a coil of wire). One of these 2 pins goes to KEY POWER (hot when key in RUN). Use your test light from a known good ground to that contact in the fuse box to confirm this.

The other pin goes to the EEC and is grounded when it want the pump on. Connect your test light directly to battery positive and then to this second contact. Have an assistant turn the key to start. The test light should come on for about 5 to 10 seconds.

The other two pins are what actually powers the fuel pump. Repeat the above two tests on these contacts. One should be hot during KEY POWER. The other supplies current to the actual fuel pump. On this last contact, with the test light hooked to battery positive, the light should come. The pump itself is the ground. The light should come, but the pump will not start because the test light is limiting the current.

If all that passes, the last test is the following. Crawl underneath and use a rubber mallet, give the fuel tank a few good whacks in a couple different places. If there is a bad spot on the fuel pump motor winding this should jog it off of that spot and the fuel pump will run.

I'm going to try and hit the pump with a rubber mallet and see if I get any pressure on my fuel pressure gage. That will save me time and I will have my verification that it is the fuel pump, then I can get a motorcycle jack, drop the tank and replace the pump. I have tried to do this once but the tank is so big, I don't think I came close the the pump.

GypsyR · 06-17-2020, 08:56 AM

Yes, our tanks are too big for the hammer trick to be very viable.

I took a chance on a cheaper pump from RockAuto. A LOT cheaper. Just the pump for like $25. But if you choose to take the more sensible high road, they have the Motorcraft ones for $330.

Note, in my case I had previously hooked up an external pump "for" a 1990 Econoline 7.5 which worked. I disconnected it when I put the proper in-tank pump on but decided to leave it under the coach. So if my cheapo pump decides to quit on me with a few minutes under the coach and I can have my back up pump going. I made it so it fits in place of the removable fuel filter. (Which wasn't easy)

Qstaar17 · 06-18-2020, 03:13 AM

I searched high and low for the motorcraft pumps that were $400 and below, couldn't find a single one. RockAuto didn't have it. Some websites were willing to take my credit card info but when I called to verify that it was in stock, they didn't have it. Ended up paying $700 for part # F6PZ-9H307-DB. Ordered it from a Ford dealership. I also brought an ATV/Motorcycle jack from Harbor Freight. Got some PB blaster too. Will continue tracing wires but I'm getting prepared to drop the 75 gal tank which is above half full. I'd say around 40 gallons. Will do it when I have time.

Qstaar17 · 06-18-2020, 03:16 AM

Smart

Qstaar17 · 06-23-2020, 12:45 AM

Quote:

Originally Posted by GypsyR

Yes, our tanks are too big for the hammer trick to be very viable.

I took a chance on a cheaper pump from RockAuto. A LOT cheaper. Just the pump for like $25. But if you choose to take the more sensible high road, they have the Motorcraft ones for $330.

Note, in my case I had previously hooked up an external pump "for" a 1990 Econoline 7.5 which worked. I disconnected it when I put the proper in-tank pump on but decided to leave it under the coach. So if my cheapo pump decides to quit on me with a few minutes under the coach and I can have my back up pump going. I made it so it fits in place of the removable fuel filter. (Which wasn't easy)

So I dropped the tank and changed the fuel pump today. The engine never sounded better. The problem is the fuel tank is still on the ground because my ATV Jack caved in to the weight, when I was trying to lift the tank back in place. I think one of the upper platforms broke. The 75 gallon tank is half full. Now I'm looking for ideas to get this tank up. Going to try and post an image.

subford · 06-23-2020, 07:02 AM

You have about 236 lbs of fuel in the tank.
I would disconnect the pressure line at the tank.
Hook a rubber fuel line to the to the pressure tap on the tank.
Run the hose to 5 gal fuel containers, (about 7 of them).
Ground pin #6 of the self-test plug.
Turn the key to run position.

After the fuel is pumped lift the tank back up with a floor jack, put the straps in place and dump the fuel back into the tank if the fuel is OK.