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Slosh Module (Solved)

Fuel pump relay... I wonder, on my 1995 Ford Ranger I would get random failure to start, turned out it was a ground. I honestly haven't checked on my explorer, if the setup is close enough. Watch this video though. And this thread.
How To: Change A Fuel Pump Relay-91-94X

 



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I tested all my relays per a thread I found on here and they all tested good. Took the Power Distribution box apart, removed the spade connectors and tightened them so they were making good contact. Finally gave up the ghost and bought a new relay. It starts right up and runs just hesitates and bucks and 35 is about top speed. Still getting 556 codes, BUT i'm only getting 10 volts to the fuel pump? Could this be the cause of everything?
 






Where are you measuring the 10V exactly? Which wire, which ground? If you can read schematics, you should be able to solve this with the diagrams I am attaching.

Here is the current path from the battery to the fuel pump:
Battery + terminal ->big red wire->starter relay lug->big black wire->Power Distribution Box
Power Distribution Box->Fuse#18->Fuel Pump Relay
Fuel Pump Relay to PCM and Inertia switch (both Dark Green/yellow wires)
Inertia Switch->Pink/black wire->Fuel Pump->Ground return to Battery

fuel_dist.jpg


power_dist.jpg


In the page below, I modified the schematic to show the inertia switch, it was added after my manual was printed.
FPR.jpg
 






Please beg, borrow, rent, or buy a fuel pressure gauge with the correct size adapter and check your fuel pressure with the engine running. It is on the left side of the engine near the front and points toward the right fender, usually covered by a hose or wire loom and looks like a tire valve.

10 volts is definitely low and probably is a bad ground or bad connection.

Get back to us with the fuel pressure and we can tell you if it is correct or low.
 






Did the fuel gauge problem and engine problem start at the same time? If so, there may be a more 'global' issue... an intermittent battery ground, something like that. I'm not scheduled to work again until Saturday, I'll try to keep an eye on this thread.
 






10V too low, what is voltage at the battery itself?
Check oump feed voltage with a different ground location
Maybe check the inertia switch connections for corrosion

Nice work thus far!
You do need to check fuel pressure, the gauge is like $40 or you can rent one
Heck I have even used a $3 round tire pressure gauge for testing in a pinch it will show you psi for a minute or five before it stops working :)
 






Where are you measuring the 10V exactly? Which wire, which ground? If you can read schematics, you should be able to solve this with the diagrams I am attaching.

Here is the current path from the battery to the fuel pump:
Battery + terminal ->big red wire->starter relay lug->big black wire->Power Distribution Box
Power Distribution Box->Fuse#18->Fuel Pump Relay
Fuel Pump Relay to PCM and Inertia switch (both Dark Green/yellow wires)
Inertia Switch->Pink/black wire->Fuel Pump->Ground return to Battery

View attachment 161302

View attachment 161303

In the page below, I modified the schematic to show the inertia switch, it was added after my manual was printed.
View attachment 161304
Thanks Roadrunner,, I measured the 10VDC at connector C141 pk/b wire using negative battery cable as ground. I also measured it at the GR/Y wire at the inertia switch, using the door hinge as ground. I read 10VDC both places.
 






Did the fuel gauge problem and engine problem start at the same time? If so, there may be a more 'global' issue... an intermittent battery ground, something like that. I'm not scheduled to work again until Saturday, I'll try to keep an eye on this thread.
No the fuel gauge problem has always been there. It started the bucking and hesitation , then we replaced the fuel pump assy thinking that was the problem, but it wasn't. Since I had a new sending unit and the slosh module was bad I jumered around the module to get the gauge to work. I am working on trying to get a fuel pressure gauge,but, if there is only 10VDC the pressure is going to be low anyway,right?
 






Yeah, I was just looking for commonality on the two issues, nevermind that thought.

At the inertia switch, you said GR/Y. Is that DG/Y? DG is dark green, GR is Grey. I'm assuming you intended green.

Time to start tracing back. Probably the next easiest spot is DG/Y at the fuel pump relay. There's a splice in-between, just need to keep that in mind if it goes 12V at the fuel pump relay. That splice, according to the book, is 'Near T/O for G100' but I have no idea what T/O is. G100 is a ground to the right front fender above and behind the power distribution box.

I think, if you would humor me, please look at the diagram I posted for the Power Distribution Box and verify that you replaced the Fuel Pump Relay with a new one? I think you said that but I'd like you to please double check. This is the most likely cause at this point.
 






Yeah, I was just looking for commonality on the two issues, nevermind that thought.

At the inertia switch, you said GR/Y. Is that DG/Y? DG is dark green, GR is Grey. I'm assuming you intended green.

Time to start tracing back. Probably the next easiest spot is DG/Y at the fuel pump relay. There's a splice in-between, just need to keep that in mind if it goes 12V at the fuel pump relay. That splice, according to the book, is 'Near T/O for G100' but I have no idea what T/O is. G100 is a ground to the right front fender above and behind the power distribution box.

I think, if you would humor me, please look at the diagram I posted for the Power Distribution Box and verify that you replaced the Fuel Pump Relay with a new one? I think you said that but I'd like you to please double check. This is the most likely cause at this point.


Thank you so much for your time. It is the dark green and yellow the inertia switch. Yes I did replace the fuel relay with a new one. I have13+ VDC at fuse #18 and 13+ VDC at connection #30 of the fuel relay. It is starting to look like I have 12+volts going into the PCM and only 10 coming out?
 






Ok... well, for what it's worth, we have it down to a physical area of about 1 square foot.... getting close!

The PCM only monitors, it is not a path to the fuel pump, so you can rule that out.

You now know your feed to the relay is +13 VDC. Now, check the output... terminal #87. There's a DG/Y wire there. It goes to a splice. One leg of the splice feeds the PCM, the other goes to the inertia switch. It's the relay (got a bad one?) something in the socket, or something in the run of the DG/Y wire, perhaps the splice. I had a different splice fail on my last year, so it's not unheard of.
 






Ok... well, for what it's worth, we have it down to a physical area of about 1 square foot.... getting close!

The PCM only monitors, it is not a path to the fuel pump, so you can rule that out.

You now know your feed to the relay is +13 VDC. Now, check the output... terminal #87. There's a DG/Y wire there. It goes to a splice. One leg of the splice feeds the PCM, the other goes to the inertia switch. It's the relay (got a bad one?) something in the socket, or something in the run of the DG/Y wire, perhaps the splice. I had a different splice fail on my last year, so it's not unheard of.


Ok, I have 12VDC at fuse 18(both sides) and only 10VDC at post 87 of relay. Only 10 VDC at the inertia switch.
 






12 VDC feeding the relay, 10 VDC coming out. It's the relay, or the socket/socket wiring. Well, we have it down to 2 square inches now!

Some relays have a cover that can be removed with a small screwdriver. If so, you can probe the guts of the relay itself, see where the 2 volts is being lost. It might be a bad relay socket. I might twist the connector blade for post 87 a little bit, just a little, to get better connection to the socket. Whatever it is, you're right on top of it. Methodically probe through it, and find where the 2 V is getting lost.

I might pull the blower relay and place it in the fuel pump socket and see if it changes anything. I wonder... there are bad people in this world that might buy a relay, and 'return' their bad one.

Good luck, I'll check back tomorrow!
 






12 VDC feeding the relay, 10 VDC coming out. It's the relay, or the socket/socket wiring. Well, we have it down to 2 square inches now!

Some relays have a cover that can be removed with a small screwdriver. If so, you can probe the guts of the relay itself, see where the 2 volts is being lost. It might be a bad relay socket. I might twist the connector blade for post 87 a little bit, just a little, to get better connection to the socket. Whatever it is, you're right on top of it. Methodically probe through it, and find where the 2 V is getting lost.

I might pull the blower relay and place it in the fuel pump socket and see if it changes anything. I wonder... there are bad people in this world that might buy a relay, and 'return' their bad one.

Good luck, I'll check back tomorrow!


Swaped out relay, no difference, tried tightening the socket. The DG/Y wire doesn't go straight from the fuse to the relay so I'm back tracking again. Have a great evening and thanks for all your help, going to lay off for tonight myself.
 






getting closer! Nice work you two
 






Double-check: Earlier, you said you had +12 VDC at terminal 30 of the fuel relay. That rules out the fuse and feed to the relay.

The possible defect points are:
The connection of #30 to the relay (supply)
The relay itself.
The connection of #87 to the relay

This is based on there being +12 going into the relay and +10 coming out, so I guess we should re-verify that?

I should have mentioned something earlier: You should be measuring all of these voltages under load, i.e. with the fuel pump running (such as it is). You have to have a load for an accurate voltage reading. A corroded connection can easily read +12 without a load and as low as nothing with a load.

Other than a quick comment here and there, I won't be able to post anything long or meaningful until early next week... my workweek starts very early tomorrow morning, and I have plans with my wife this afternoon/evening. If you were making these measurements with the pump off, please go back and take them again with the engine running. It's a big difference, believe me, I lost 4 hours on a repair last year because I didn't think this through. You have to have a load for accurate readings.
 






Double-check: Earlier, you said you had +12 VDC at terminal 30 of the fuel relay. That rules out the fuse and feed to the relay.

The possible defect points are:
The connection of #30 to the relay (supply)
The relay itself.
The connection of #87 to the relay

This is based on there being +12 going into the relay and +10 coming out, so I guess we should re-verify that?

I should have mentioned something earlier: You should be measuring all of these voltages under load, i.e. with the fuel pump running (such as it is). You have to have a load for an accurate voltage reading. A corroded connection can easily read +12 without a load and as low as nothing with a load.

Other than a quick comment here and there, I won't be able to post anything long or meaningful until early next week... my workweek starts very early tomorrow morning, and I have plans with my wife this afternoon/evening. If you were making these measurements with the pump off, please go back and take them again with the engine running. It's a big difference, believe me, I lost 4 hours on a repair last year because I didn't think this through. You have to have a load for accurate readings.


Thank you so much for all your time and advice. I will recheck these things. Please have a great weekend. I will keep this thread updated. I hope I am close, I am starting to get a little tired of this project. LOL
 






Using page 24-5 from the post by Roadrunner If I understand it right, at the fuel pump relay. #30 is hot all the time. Post #85 becomes hot when the switch is turned on causing the relay fo go from #87a to #87, correct? Well #87 is hot even without the relay plugged in, any thoughts?
 






#87 does go hot, but only for the first second after you turn the key to 'on'. This pressurizes the fuel rail. (you don't want to run the fuel pump constantly on a stopped engine). The PCM will close the relay again if it senses that the engine is running. Repeat what you did with the engine running and it will make more sense. I'm off my workweek, so I will be checking in more frequently until Friday.
 



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Thanks Roadrunner, ok here is the latest update. Discovered that even though the #18 fuse was good, the contacts were not so there was no voltage going to GN/Y wire. Don't know where it was coming from before. I still have 10volts to fuel pump and relay, until, I start engine then have full 12VDC.. According to Ford manual you have to drive at least 10 miles after any changes for them to be recognized into the system. Drove the ten miles and seems to be doing great. Got it up to 75 on hwy, came home read codes again, still have 556 in KOEO and 211 in memory, KOER were : 172,136 42, I cleared the codes, going to to drive it again and see how she does.
 






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