Ford Fuel Pump Power Diagnostics

Here we show how we diagnosed 3 separate problems in the same power circuit on a 1996 ford f-150

[@MrTechnonesis]

Watched four different videos. They all stopped before the ECM Diode. I pulled out the diode and put it back in and she started right up! Thank you. Thank you. Thank you!

[@chetmyers7041]

Clean terminals on that DIODE socket!

[@stevepurcell7266]

Finally a no nonsense salt of the earth guy. No B.S. just great guy.

[@TheCrofolks]

Great video with detailed, yet common sense explanation and demonstration for what can be a confusing and difficult situation to diagnose and repair, especially for those of us who are non-mechanics. Many thanks, as this significantly aided my troubleshooting on my 93 F150.

[@raycer27]

1996 F 150 5 liter app.200,000 miles. My faithful starting truck wouldn't start. It would start on the 1st revolution,then I went to start it one day and it kept turning over...no start. I turned the key on & off cycling the fuel pump relay,still no start. Sat for about 10 minutes,tried to start,this time it started and for about a month everything was ok,then it became a problem once more. Things I have done so far;I watched a Utube video Eric the car guy & Scanner Danner on how to diagnose this problem,but had no success with that. my truck sat idle for almost a year while I fixed other things. I watched another video that showed how I can test the coil with a test lite.This truck hadn't run for 9 months,though I would try to start it occasionally. So I tested the B+ side,had juice going in,I turned the key on,used my remote starter across the solenoid and checked the pulse side to see if the lite was showing a pulse,it was not.then I checked it again and it started up and ran. Starting it this way wasn't always successful. I changed the connector going into the coil,& replaced the coil,I thought that would solve the issue...wrong. The next thing I tried was a new TFI,sometimes it'll start,sometimes it won't and I have to touch the testlite to the pulse side of the coil and most times it'll start. When it starts & runs it runs great,no miss fire,it's perfect. I'm obviously missing something and my reader doesn't show any error messages. I haven't changed the pickup coil in the distributor because of how good it runs when it does start,like how could that be the problem if it runs that good. There is a tiny electrical plug that's attached to the TFI harness,but I don't know what that's for. If I could figure out the significance of the testlite as to what and why the testlite is the key to it starting to the secondary side of the coil,if it was a ground issue,why would it then run after starting with the lite? I didn't want to replace parts,hoping that I would fix it by trial & error,that's too costly & I'm on SS I guess my brain is just fried....any ideas will be appreciated. Dewey & I have spoken about this problem and he has given me some things to check out & will get back to him with my findings. This guy is the real deal,folks! I wish I lived closer to him,I'm in south Florida and he's in Canada! Y'all should subscribe to his channel,he's a good guy! Thanks for your help,Dewey!

[@ianconley6673]

Look into the tank selector switch if you have dual tanks or your fuel pressure regulator. Also check the fuel pressure to male sure that is ok first. It might be a pump going out. Check the first two first though and the pressure

[@bigjeff719]

Thank you for what you do, I took that relay out of my 92 and compared them and threw it in my 95 and it started right up thank god... I hope you know alot of us really appreciate peolpe like you, 👍✌

[@garywiley73]

This guy is great great great. He explains things simply and straight to the point. Yahoo needs to keep him doing videos

[@lyndleshelby6291]

Sir, you are an excellent instructor! Amazing video.

[@stevemyers2852]

Man thanks so much! All I did was push in the ecm diode and truck started right up! 1992 Ford F-150 xlt, hope this helps someone else!!

[@Purosanluispotosi]

I put new fule pump on my f150 1995 rear thank and start and die but if I switch to that from start whit no problem than I switch back to that rear and works but file like up hills loose power

[@jayjohnson5077]

Nice job explaining all the info, very easy to understand and repeat in the flesh.

[@youngguns1319]

Great video love how you go over the whole system

[@robertegibson9434]

I've watched several videos and this Real Mechanic is an excellent troubleshooter!

[@TheCaddyMan1406]

Thank you so much I literally was about 10 minutes away from hardwiring the fuel pump in my truckThis helps so much I forgot all about that damn inertia switch

[@infinitenoodle7894]

great video. I have this issue with my truck right now. i will check all of this. thank you.

[@valentinrieuf9983]

FYI on a 1994 Bronco, the inertia switch is behind the side kick panel on the passenger side.

[@rockyjones6332]

Thank you so very much! Absolutely every troubleshooting video should be modeled after this one. Great job! Reminds me of a time when the internet was a reliable source and straight to the point, circa dialup. I swear it takes more time and entirely too much frustration to weed out the B.S. Again Great job! Btw this is my first time commenting any video due to not having anything nice to say.

[@noecampos1359]

Clear. You go direct to the problems. Not bla bla bla like others thanks a lot

[@Dougyelnats]

Thanks finally someone who can walk you thru. Same problem will go try your suggestion

[@seetheforest]

Damn you Henry Ford! Thanks for posting this. My 93 f250 6l is having a front tank issue.

[@davidasleson2586]

Thank you-valuable information and simply explained for me to understand.

[@Devoneakapimp]

Where do I start... I bought a semi busted 1994 f 150 from a homeless man for $1k. 3 hours into the trip home it stopped running. I suspected it to be the fuel pump as the gauge level wasn’t working and fuel over flowed from the tank. Long story short, after sitting for months, replacing the starter battery and fuel pump, it still didn’t run. The hose that’s supposed to recycle vapor was detached, causing gasoline to overflow from the tank. The old fuel pump only had two wires running from it (positive and ground) The other two wires from the pump were cut off, which explained the reason I couldn’t read the fuel level. The positive was ran directly to a random positive harness. I had to undo all the bull shaz and connect a new pump properly to the wiring harness. Still, no power. Now I’m thinking maybe the previous owner wired it like he did as an inexpensive alternative to making a fuel pump relay directly to the battery due to not getting enough voltage to the pump. So my next step is to check the inertia switch, tank selector, ECM diode, relay, fuel pressure and pump. If I that doesn’t solve the problem, direct battery connection is a must.

[@quinnstigator]

Thank you for clear explanations.

[@byronleatham1183]

I've been searching trying to figure out why it will start but then the fuel pump doesn't Pump Fuel again I never thought to check that dialed I didn't know anything about that had anything to do with this song I really appreciate you don't

[@alpinehs]

Great explanation of a problem. Thank you for sharing.

[@curtschloss4032]

Thanks good job walking through the scenarios

[@travis5993]

Thank you. I am working on the same problem and this was vary helpful

[@lorrainehoffman1307]

Thanks for a great troublshooting video! Loved it.😊

[@paulj541]

It always makes me happy to spend a couple hundred bucks too.

[@UnderDog1911]

Real troubleshooting! Well done!

[@bmead144]

Dude-thats one gnarly beard!!

[@kevinwellman6406]

Great video!

[@steverusinowski9149]

Thanks for very informative video. I have a 94 F 150 that will only feed from the rear tank. I pulled the bed and replaced the front fuel tank pump and presto. All works. Next day no run on front tank. After watching your video I checked the inertia switch, swapped relays around, Checked diode with meter. Found only 6 volts at the front/rear selector switch. What feeds 12 volts to thisswitch? Where can I get a schematic? I went to the library, searched the web. No joy yet. Like to know what the next item is upstream of the switch.

[@tri-rrrservices7299]

The inertia switch feeds power to yhe selector switch, you will need to check power in and out there next.

[@DDFJ1230]

This helps a TON. Thanks!

[@WillyPete_]

04:09 ECM Diode, Simply Remove & Replace for better connection. THANKS FIXED MY 543 Ford OBD code. Power restored.

[@bryansalter7883]

Thank you!! For the Video!!🙌🏼🙌🏼👍🏼👍🏼💯🇺🇸🙏🏼

[@mikeortiz1018]

Great video. Will power be available in those locations with key in and turned?

[@ericstrong1033]

awesome video my friend simply explains straight to the point just awesome.

[@homeoftheblueflame2724]

I gotta 94 f150 same problem but I took the ecm out to check if it is getting power but it’s not gettin power to the slots it goes it what could be my problem?

[@idawilliams7986]

Good info sorry to see thumbs down piss me off to see it .but it's just some one who ain't got a clue on viewing good help probably ain't got any clue on fixing anything either ..thank for your time on showing leads got one to do tomorrow 👀all info helps

[@juanrubalcava5111]

Your the man! Just subscribed.

[@chiefjaspil]

Very Good. Hope you can help me. I have the same truck. sat 3 years. I replaced front tank, treated fuel cleaned throttle body all good then was going to replace the rear tank and just prior to mounting the tank I thought I would check the voltage on the rear harness. I got like 5. something volts. Went to start on front tank pump would not run. checked voltage on new selector switch. NO voltage, checked relay, inertia switch all good. An idea? Thought I would just connect the new rear pump not installing it in the tank and see if it would run. I am out of ideas

[@tri-rrrservices7299]

Check the diode like I showed, but likely bad grounds, check for mouse activity too.

[@chiefjaspil]

I have not gotten back to the truck I will go through it again and I think I will just purchase a new Diode. prior to my note to you I did pull it and clean it with same results. I promise I will let you know the problem your video is clear and should produce results for me promise to let you know AND Thank you for answering me, Jim

[@karlwendel8699]

Thank you! Exactly what I needed.

[@JoseLopez-tb5mk]

Where you located...does a f150 1991 have an under the hood fyse box?

[@patrickgodman2429]

nice diagnostics. i have a 95 f150 that runs on rear tank only. i replaced front tank pump and wiring plug that came with new pump. original pump was clearly bad (rotted off strainer and sludge inside plastic pump housing) i reinstalled tank and pump did not function. replaced selector switch still doesn't work. still works on rear but front still doesn't make noise when key is turned on. relay "clicks" on front tank initially when key is turned on but no noise from pump. any suggestions? you're the first channel i've ever subscribed to! thanks for the knowledge. patrick

[@tri-rrrservices7299]

Thanks for the comment and subscription, first thing to check is for power and ground at pump plug, sounds like it is likely a ground problem, check for power and ground with a test light to make sure circuits will carry a load.

[@patrickgodman2429]

@@tri-rrrservices7299 that sounds logical. thanks. do you know which wire is ground, and where it is grounded on the chassis? red with yellow stripe is positive?

[@tri-rrrservices7299]

Typically the 2 outside wires on the fuel pump plug will be the power and ground, and the center ones will be the fuel guage, so with key on you will have 2 powers, one for the pump and one for fuel gage, the pump wires should be at least one size heavier than the sensor ones, you also want to ensure you have the wires spliced correctly. You can also check fuse 6 in the i/p fuse box as that should operate the tank selector on the frame, but if the rear tank is shutting off it most likely is working.

[@patrickgodman2429]

hello, well after a few hours of checking wires and switches with a volt and continuity meter and couldn't find a problem i made a jump wire from the battery and tested the pump at the plug and found it didn't work! so i dropped the tank again. gerrrrrrrr! turns out the crimp connector the parts store used to assemble the pump to the rest of the pump assembly in the tank was not crimped correctly causing a false connection! counter salesman was sorry, but not as much as i was having to pull the pump and tank twice. bench test parts first !@@tri-rrrservices7299

[@tri-rrrservices7299]

The faulty new part problem gets all of us once in a while, and I would suggest using a test light instead of a volt / ohm meter for testing the circuits, as a meter won't load the circuit in the case of a bad connection, and good job o getting it diagnosed, hot wiring is a legitimate test.

[@dustinjeffries7226]

What would you think. Fuel pump works can jump and make them run good fuel shut off switch. Good diode but no power from the cab harness to to fuse box? Can run a jumper wire with fuse inside the cab to fuel pump make them run all the time but won’t prime off the key

[@tri-rrrservices7299]

Check the roll over switch behind the right side kick panel

[@HeMan-cr1fo]

This is a great video thanks

[@nen.user.3764]

Thanks man. Great work.

[@michaelmcnabb5760]

Good information, thnks

[@tommyt7106]

Great video very informative make more videos like this pls

[@1000MileVision]

THANK YOU MY 1987 ACTS QUIRKY THIS WAY

[@modocroughstock5700]

I just just knew a red bearded guy would have the answer.. I thank you

[@Paulilmys]

This helped me tremendously

[@romulospiller2352]

Awsome, thanks for the update!

[@JD-ml7cg]

Hey nice vid, do you know if the diode can cause a no spark ?

[@tri-rrrservices7299]

Diode is only in the fuel pump circuit, no spark is commonly the TFI module on the distributor on those older Fords

[@JD-ml7cg]

@@tri-rrrservices7299 thank you!! I will changing it today

[@QLFProductions]

She cranks but does not start. Did most things mentioned in this video except I paid no attention to the diode. I have no fuel pressure so I think I'm going to verify that I have power to the pump and if so replace the fuel pump. When you say bypass the inertia switch you mean join the two wires right?

[@RollingThunder85]

Iv replaced 3 fuel pumps in 6 months if I keep flipping tank selector switch it runs fine but in a few minutes fuel problems again

[@josephleister9198]

Nice work....thank you

[@felixcalderon574]

Very good job thanks

[@JasonSmith-qx3zh]

How did you check the diode fuse thingy????

[@tri-rrrservices7299]

You can use a diode checker on a multi meter, it runs a current through it in one direction, but I commonly check them just with an Ohm Meter, as having a connection is the point, it being a diode is for RF noise suppression from the pump motor, you can also use a jumper to confirm connection for testing purposes.

[@JasonSmith-qx3zh]

@@tri-rrrservices7299 Thanks TRS a million!

[@JasonSmith-qx3zh]

I fix my no spark from on here, so I have a no fuel no start, which did start after I shot starter fluid in it (95 f150 4.9l) with the dual tanks and with this video I have confidence anyway thanks for all you do it is appreciated!

[@Kistilan]

@Tri-RRR Services, did you have any obd1 codes pulled? I am at your video with a no-start on my 97 f350 auto and pulled a 542 fuel pump open circuit or ecm code. They just replaced the fuel selector switch and don’t believe the inertia safety is tripped or bad (those things are resilient in my experience), but that ecm relay I had no idea. I have a feeling my 92 f150 is in limp because of that and this new-to-me f350 is possibly suffering from a bad connection there too. However, wanted to check on any obd1 codes you had pulled.

[@timothyshannon6750]

Could you please tell me why I have a light throttle.

[@ronaldjensen8927]

87 F150 doesn't have that power distribution box there. Is the 87-95 speed density version a lot different?

[@Airsally]

Got any ideas why a 2003 mercury mountaineer no fuel pump prime when you turn key on. Car will start after cracking to get oil pressure car starts and runs fine. Just harder to start when it hot. .

[@tri-rrrservices7299]

Likely the temp sensor, there are 2 one for the guage and one for the computer mixture control, if the mixture control one goes bad it can cause hard starts as it typically causes a flooding situation.

[@Airsally]

@tri-rrrservices7299 it's not running rich ,and isn't flooding . You can not hear the 2 second prime when you turn the key on. Once the car has 4psi of oil pressure the pump come on and car will start. What tells the pump to prime?

[@tri-rrrservices7299]

The ecm runs the prime, if it's not priming you will need to check inputs and outputs of ecm, in particular you want to check the ground circuit for that circuit in the pcm as there are multiple grounds for multiple functions I the ecm, that will require a wiring diagram to confirm which circuit as well you will want to use a test light for checking power and grounds, as an ohm meter won't show if the circuit is unable to carry sufficient load.

[@curtiswilson7957]

F250 7.3 related switch

[@runenramirezsandoval9134]

Where are you located? I have the same problem.

[@MrWeedpatch]

Thanks so much....I'm debating on a 95 Fi50 with 6 that runs like shit...If I go for I'll be totally at your mercy...These Fords are great when they but no one seems to be able to fix them...

[@MrWeedpatch]

Just wanting to add it will start was making a knocking noise when shut off. It’s a 4.9 6 with a 127k miles if anyone has a clue.

[@MrWeedpatch]

Sorry meant it will not start

[@RustyNutzTruckz]

Will that dio or whatever you called it in the fuse block there cause the fuel pumps to keep priming went you turn the key on? Cause I'm almost out of sensors to replace on my 97 f250.

[@lavernepeters2239]

I have the same thing.i put a brane one it worked for a little bit now I don't full going to it it is a 1992 ford f 150 2 well drive . How do I test the relay for it

[@outlawaudio971]

How can u tell if the nurse fuel is trip

[@westerndevil8034]

I got no power to my switch, so what’s the problem?

[@partyboy0319]

Is it normal for fuel selector switch wires to get hot and on the diode when checking it how did you check it to make sure it's good.

[@tri-rrrservices7299]

Wires should never get hot, there must be a shorted wire somewhere, the diode can be checked with a digital multimeter that has a diode tester option, a basic test is with an ohm meter to ensure it has a connection through it, or test fir voltage on both sides when plugged in and powered up, a diode is just a one way check valve for electricity.

[@partyboy0319]

@Tri-RRR Services my diode only shows olvoltage on one side with my powerprobe. And I'll have to check in those hot wires maybe bad relays they feel a little hot to

[@tri-rrrservices7299]

It needs voltage on both sides when plugged in, unplugged will only have voltage on the side coming to it, relays bring hot is a result of to high a load, the relays themselves are very rare to short internally

[@partyboy0319]

@@tri-rrrservices7299 I'll have to look into it. Thank you for the reply.

[@mase202]

my center power orange with yellow strip reads 6.6 volts im trying to figure out whats going on in the inertia green yellow cable its also has 6.6 volts my fuse for the pump has 12 volts and i do hear my relay click any idea what could it be? this is the best video i have found for my problem. thankyou for your time

[@tri-rrrservices7299]

I assume you're talking about the wires at the fuel tank selector switch? If your getting 6.6v in that's all you will get out. You need to check you supply power, I would start at the relay, just because it clicks doesn't mean it is putting power out, jumper your 30 and 87 terminals at the relay, and check that there is 12 volts, then check for power at switch, if it is good, change the relay.

[@mase202]

Tri-RRR Services thankyou for your quick response yes 6.6 volts on the wire (orange/yellow)on the gas tank switch selector. I assume there should be 12 volts i did switch the relay with other relays in my box but still reads out 6.6 volt. so it should have 12 volts and not 6.6?

[@tri-rrrservices7299]

Has to be 12 everywhere, check your voltage at the relay, pin 30 should have 12 volts at all times, sounds like you may have to chase down a bad wire.

[@kevinmcguire6933]

how did you jump the fuel selector switch

[@mase202]

can you please tell me what connecter pin you touched to power the fuel pump directly? there is 4 pins im not sure which ones i should touch to see if the pump turns on. thankyou

[@tri-rrrservices7299]

I believe you said before that you had 6 volts at the connector, you need to supply 12 volts to that pin while it is plugged in, and pump should run, this will confirm pump is working, you will also need to track down the reason for the low voltage. If voltage goes to 12 with connector unplugged then it could be the pump or bad grounds.

[@mase202]

Tri-RRR Services thankyou for your reply i have 12 volts on my fuel pump relay connector and my fuel pump fuse but for some odd reason when i check my inertia cable that goes to my tank switch then to my fuel pump it only shows 6.8v.Not sure why? Your video is the best out there that matches my problem.I want to test the fuel pump with a power probe would you know which connectors i should add power and ground ? the connector is round with 4 pins. thankyou

[@uzikilla69]

@@mase202 You need to get a wiring diagram for your vehicle, try looking it up. Or better yet a service manual for your specific car. Wish you luck bud, I'm obviously having a fuel problem as well. Think it's my ccrm

[@VWtech562]

You don't need to jump the switch directly. Go to the obd1 connector and with the key on the run position ground the pin located on the right side of the obd1 connector. It will send power directly to the pump. Move the tank selector switch to check both tanks.

[@aguilareal6537]

Good job bro👏🏼👏🏼👏🏼👏🏼👏🏼👍👍👍👍

[@georgekofinas5863]

Sounds like one of the few knowing what your talking about. I'm on my way out to check the reset switch mine is behind the tail light it's a windstar van. IF I can't fix it, what State are you? you might want to look at it ah!

[@tri-rrrservices7299]

I'm actually in western Canada, but let me know how you make out.

[@davidvonanderseck8649]

Wow thanks for this video

[@daveysprocket3946]

U know ur chit! Thanks a mill.

[@Lenny4400]

Hello l have two fuel tank s.lf one fuel pump goes out can the second tank be used?

[@tri-rrrservices7299]

Yes, just leave it selected to the one that works.

[@robertyeary5531]

I have no pressure at all does that mean a bad sending unit

[@tri-rrrservices7299]

You need to confirm if the pump is running, should be able to hear it for a couple seconds when you turn the key on, if it's running but no pressure, then likely the pump, if it's not running you need to made sure the pump connector has power, if it does then it's the pump.

[@outlawaudio971]

Ok I have a 1986 and I don't have no power going to my fuel pump

[@petergilchrist2805]

thanks

[@outsidedog8205]

Dude thank you.

[@erictyner2162]

Would the wireing be the same on a 94f350

[@jerrellstrawn6409]

Thanks.

[@myownthoughts969]

I’m having the same problem. Can you tell me which holes in the pump relay go to which things. I have power at the far right hole but no where else. Which hole is the control ?

[@chetmyers7041]

Haynes Manual is your friend. Best $30 you can spend.

[@bencox3195]

How did you jump the inertia switch??

[@tri-rrrservices7299]

I didn't, I checked to make sure it wasn't tripped, then checked that it had power on both sides

[@bencox3195]

@@tri-rrrservices7299 ok. So,what voltage should i have at the switch?

[@tri-rrrservices7299]

Battery voltage, nominally 12 volts

[@kingoncommonlaw130]

Thanks man

[@hellow9155]

I don't have a fuse box under the hood so.... sol

[@treychum]

It was that damn red button

[@nathanscullawl3331]

I had this same problem. It was the problem

[@sweethomeTN731]

Any reason a fuel selector switch would keep being blown? It happens intermittently maybe once a year or could happen twice in one week. Again it happens randomly and always when starting the vehicle. Sometimes it only blows on the front portion of the switch and the rear still works. Vice versa. I feel like this is a massive issue with these setups.

[@tri-rrrservices7299]

I would expect you have a poor ground between the engine and chassis, or battery and chassis, and the switch is a victim of high current load on startup, the part of the switch that burns out is likely the tank selected at the time. doing voltage drop testing is about the only way to find the problem, but an occasional problem is very hard to find as you can only really test for it when its happening and you don't know when that is going to be.

[@jberejik]

Thank you!

[@lvgeorge]

I see a Human Fire Hazzard!

[@crawlspaceemora]

Mmmmm❤

[@Watchout1010]

We tell no year or model,very helpful,not.

[@0believeinjesus9]

Gods son Christ Jesus died on the cross for our sins so that by believing in him we can have life...belief in Christ Jesus be a free gift from the father, given to them [ through thee hearing of heth words ] whom he hath chosen for salvation....

[@charlesdriggers5184]

,

[@Devoneakapimp]

Where do I start... I bought a semi busted 1994 f 150 from a homeless man for $1k. 3 hours into the trip home it stopped running. I suspected it to be the fuel pump as the gauge level wasn’t working and fuel over flowed from the tank. Long story short, after sitting for months, replacing the starter battery and fuel pump, it still didn’t run. The hose that’s supposed to recycle vapor was detached, causing gasoline to overflow from the tank. The old fuel pump only had two wires running from it (positive and ground) The other two wires from the pump were cut off, which explained the reason I couldn’t read the fuel level. The positive was ran directly to a random positive harness. I had to undo all the bull shaz and connect a new pump properly to the wiring harness. Still, no power. Now I’m thinking maybe the previous owner wired it like he did as an inexpensive alternative to making a fuel pump relay directly to the battery due to not getting enough voltage to the pump. So my next step is to chec