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Kenny Z.
Kenny Z., Lincoln Technician
Category: Lincoln
Satisfied Customers: 5386
Experience:  Lincoln Senior Master
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99 lincoln navigator: mileage..alternator..crank..fuel pump

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99 lincoln navigator died while driving ...and now will not start back milage now shows ------ instead of mileage. Battery is new, alternator fine ......will crank like its about to start but will not start. fuel pump will not come on. The Inertia switch has 0.51v going in and coming out. When the key is turned on you hear the normal beeping like the door is open (about 7 times) than a single diffrent tone followed by the same tone going 5 times then pauseing and then going 5 more times. it keeps repateing this. most of the instrument panel lights do not come on like they should. when i was driving it all happend within one mile, It started to shake and run like it was missfireing so i coasted for a 1/4 mile then got back in the gas and it felt the same and then just went dead. lights on gauges were out motor was dead and i was rolling at 45mph in gear. so i put it in nutral and coasted to the side of the road. The only blown fuse was the #4 25A Console Powerpoint fuse. power is present to both relays, fuel and pcm. got one new relay and swaped out the 2 old ones around. and still nothing. no power to the fuel pump.

Thank you for using just answer.
My name is XXXXX XXXXX i will assist you today.


I know you said the fuses was good but i need you to check # XXXXX and # XXXXX in the battery junction box. Swap the pcm relay and fuel pump relay with another one. If all are good check the dark green and yellow wire going to the inertia switch and see if you have power. Also make sure the button is pressed down in the switch. Make sure the key is on when checking power

Customer: replied 7 years ago.
inertia switch dg/y Has 0.51v. all fuses have been checked and relays have been moved meny times. ther is a box that is just behind the fuse panal by the drivers leg that Beeps 5 times then pauses then beeps 5 times and so on when the key is in the on position.
Does the pink and black wire have voltage?
Customer: replied 7 years ago.
ill check
Customer: replied 7 years ago.
NO. also whin i hook up the obd2 scan tool it says Fail.

If you are getting voltage going in but not going out and the button is pressed in the switch then the first thing to replace is the switch. This is not a common part failure but voltage doesn't lie. I am giving you a wiring diagram to look over. The parts were wires are coming in is from the fuses that is good.




Customer: replied 7 years ago.
When the switch is pluged in it passes the same 0.51v . So the switch is good
So when the switch is plugged in you get voltage on both sides?
Customer: replied 7 years ago.

If you do have power to and from the switch and the pump will not come on then there are 2 options the fuel pump and the cluster. SInce you said the cluster will not read the mileage and looking at the diagram the cluster has a built in fuel reset switch indicator. The cluster could be the problem. Check the grey and orange wire to the switch see if it has power. Also check the yellow and white wire going to the fuel pump and see if you have power. This will let you know if the cluster is sending voltage to the fuel pump. Also while you are at the pump check the pink and black wire to see it there is not a bad wire from the switch to the pump. Now i want you to get a hammer and hit the bottom of the fuel tank and see if the fuel pump is froze. Sometimes this will let it start.If it does start replace the fuel pump

Customer: replied 7 years ago.
I am currently in proccess of changing the fuel pump out. B/c it is time anyway. I hooked up a jumper wire to the pump to test it and it ran fine. I want to get the electrical prob under control befor i put the tank back in . ill look into the cluster voltage once i read your last post a fue more times. thanky you so far. ill be back in a fue.
hey glad to help you.
Customer: replied 7 years ago.
want to be clear on what im looking for on the gauge cluster. I need to take it out and locate the grey and orange wire and test for voltage going into the cluster? should the voltage be 12 volts at the fuel shut off switch not 0.51v? the yellow and white should have haw meny volts going in to the pump?
Customer: replied 7 years ago.
Relist: Incomplete answer.
Customer: replied 7 years ago.
"want to be clear on what im looking for on the gauge cluster. I need to take it out and locate the grey and orange wire and test for voltage going into the cluster? should the voltage be 12 volts at the fuel shut off switch not 0.51v? the yellow and white should have haw meny volts going in to the pump?"

Is this what i need to do next?
Customer: replied 7 years ago.
With the cluster removed the grey and orange wire has no voltage. should the cluster be pluged in when testing?
Customer: replied 7 years ago.
with the cluster pluged in it has 10.87v
Customer: replied 7 years ago.
can someone help me!!

Hello, this is Kenny Z.
Your satisfaction is my goal.Please ask as many questions as needed before clicking the accept tab.


I really don't know why he has you checking at the cluster. Here is what you need to check. pull the fuel pump relay and find the pin numbers marked on the relay. Now you know the terminal numbers for the fuel pump relay terminals in the fuse box. check for battery power at pin 30. If no good let me know. If good then install a jumper between pin 30 and pin 87. Now see if the fuel pump is running. Let me know these results and we will proceed from there. I think we have another issue here I just want to quickly verify the secondary side of the pump circuit so we can move on to the real problem.

Customer: replied 7 years ago.
87 not 87a correct. Ill go test for voltage at 30 and then jump to 87
Thats correct 87a is a dead hole
Customer: replied 7 years ago.
ill go now. be back in 5
Take your time..
Customer: replied 7 years ago.
The pump kicked on

Great! Let me apologize for the other expert, I hope this is not a reflection on the site, most of us actually know what we are doing here.


Ok now check pin 86 with the key in the run and with the key in the start position Looking for battery voltage in both positions, it might be a little lower in the start position due to current draw from the starter. Let me know....

Customer: replied 7 years ago.
86 had 0.85v in the run position
Ok that is no good. What does fuse 18 show in the battery fuse box with the key on?
Customer: replied 7 years ago.
11.52v on #18
Both sides, correct?
Customer: replied 7 years ago.
I pulld the fuse so i could check, one side had and the outher did not
Ok, I will assume the voltage is getting across the fuse for now. You have an open circuit between that fuse and the fuel pump relay coil feed. Unfortunately this fuse feeds a bunch of other engine control components also. The wire splices off and feeds the PCM and some other sensors on the engine. I need to find out if the open is before or after the splice. I am thinking there is no power to the PCM and it is off line. That is why the IC is displaying dashes and other modules are beeping, because they have lost communication with the PCM. The wire color in question is red. Find the mass air flow sensor and check the red wire with the key on, you can do this with the sensor disconnected. This is after the splice and will help indicate where the open wire is.
Customer: replied 7 years ago.
Ok, we need to concentrate between fuse 18 and the splice. I would start right at the fuse box, I see a lot of corrosion and broken wire issues in this area. Pull up the fuse box and flip it over and remove the bottom cover to expose the wiring. (you might want to disconnect the battery until you have it in position. Now find the red wire coming out of fuse 18. The violet wire is the feed that showed good voltage. Visually inspect the red wire for any corrosion at the fuse terminal, and then as far as you can see it. If you don't find anything obvious then reconnect the battery make sure fuse 18 is installed and check voltage right at the terminal where the wire is crimped to the terminal. If good then you will need to pierce the wire (you can seal it with silicone later) and move along to see if you can find the spot where the voltage drops. If the voltage stays good all along the length of wire that you can get to then you will have to start opening the convolute to open the harness to keep exposing more and more of the wire as you go along and test right up to where the splice is. You should find the problem before the splice as we know 2 components after the splice are not getting proper voltage. Good luck and let me know what you find...
Kenny Z., Lincoln Technician
Category: Lincoln
Satisfied Customers: 5386
Experience: Lincoln Senior Master
Kenny Z. and 2 other Lincoln Specialists are ready to help you
Customer: replied 7 years ago.
The Violet wire's are on the very opposet side of the box than fuse 18 when looking from the bottom. the violet wires have the same voltage as all the red wires on all the sensors do. so if the violet wires are the feed to the red then their low voltage is the problem?
You said you pulled the fuse for 18 and had 11.52 volts which is good. The violet wire is the feed for the fuse so that was the wire you were checking If it had 11.52 then the problem had to be on the red wire which is on the other side of the fuse. Are you now saying that the violet wire has low voltage???
Customer: replied 7 years ago.
on the under side of the box their are 4 larger Violet wires wetch read o.85v The same as all the red wires i have been looking at. the # XXXXX fuse that i checked from the top of the box by pulling the fuse had 11.52v
Ok all of the other wires do not matter at this point. If the violet wire that actually connects to the feed side of fuse 18 has 11.52 with a good fuse installed the red wire coming from the other side of fuse 18 should read 11.52 volts also. Is this the case or no? We need to stay just on this one circuit for now. This is the only red wire that feeds the fuel pump relay and the mass air flow sensor which we know have a low voltage problem.

Here is a PIC of the circuit.



Customer: replied 7 years ago.
Ok It was # XXXXX i checked (30a Pcm) # XXXXX has low voltage from the violet. all the violets have low voltage. sorry for that.

No worries.

Ok If you can flip the fuse box back over and pull the PCM relay, same thing, note the pin numbers and at the terminals. Check pin 30 for battery voltage. This should show battery voltage all the time.

Customer: replied 7 years ago.
I have done that i know it is their. ill go make suer agin though.
Ok if pin 30 is battery voltage all the time, then check for battery voltage at pin 86 in the run and start positions. it should show battery voltage in both positions. If no good then check fuse 30 in the INTERIOR FUSE BOX. If ok then check for ground on pin 85. If you jump pins 30 and 87 the vehicle should start and run. I am going out to dinner with my wife so I will be gone for a few hours. Probably won't be back online until about 8-9 PM Pacific time.
Customer: replied 7 years ago.
No worries we will pick this up tommorrow.Have a nice Dinner.
Ok Thanks. Have a good night.

Good Morning. I will be heading out to church and some family events shortly - just wanted to see if you had any results from the PCM relay wiring checks or not.

If I am not online I will check back in with you as soon as I am available.





Customer: replied 7 years ago.
Morning kenny. I did as you said and was able to get it running by jumping 30 and 87. fuse 30 was bad so i changed it. it started and runs now. so i put the relays back and tried it and its good now on the electrical end of things. but i suspect it is running very rich now because of the fuel pump i just put in. it smells like sulfer and is a little less responsive. The shop that i got the fuel pump from said it would work fine the extra fuel would just be returned to my tank. I Installed a Walbro 255 lph pump because i am planning on supercharging it with the lightning's whipple supercharger and will need the extra fuel and thought it was going to work like he said it would by returning the extra fuel to the tank. but i think it also increased the pressure also.

So my new ? to you is can i put an adjustable fuel pressure regulator and fuel gage on the fuel rail to control the pressure. and witch of my 4 o2 sensors is best to use for an air fuel gage.

Also should i start a new Question. I do plan on using this site as it is intended to be used. so if you can let me know How i should do this i will continue to Accept your help with my truck.

Thank you so much, you truly Know your stuff.


Hey Robert,


Glad you got it running. To be honest I know nothing about these other items you mentioned. I'm not much on the aftermarket side of things, though I have built some performance racing transmissions. I would recommend opening a new question and hopefully one of the experts has experience with the additional items you need advice on. Good luck to you and take care.



Customer: replied 7 years ago.
what will cause fuse 30 in the INTERIOR FUSE BOX to keep triping 2 sec after it starts up. i had a bad coil that was the poor accelaration problem. so i changed it and the plugs and it started and ran very nice for about 20 sec then i herd the fuse pop and it died. so i replaced it with a new 30a fuse and got it to run for 2 sec. then it poped

That is a bummer!


Quite a bit on that circuit. Coils, PCM relay (coil side only), cluster and pats key transceiver.If it never blows with the key on only when running,then its probably not the pcm relay circuit or the pats transceiver or the cluster. If I had to guess I would say coil circuit? You could unplug one at a time and see if the short goes away. You might get a circuit breaker for that fuse for testing so you are not having to constantly replace fuses. The key is that it does not blow until it runs. The only current draw that is changing would be the coils firing. I doubt its a wire if it were it should blow right away with the key on. If it does blow with just the key on and the engine off then all bets are off and it could be anything which means process of elimination by unpluging components one at a time, disconnecting circuits one at a time.

Edited by Kenny Z on 6/15/2010 at 2:22 AM EST
Customer: replied 7 years ago.
i just replaced one coil because of infanent secondary resistance. but the rest tested good. can you describe the process of unpluging and seeing if the short goes away, while I accept your previous answer.
It amounts to unplugging one coil then running the engine to see if the fuse blows, then repeating for each coil.(only have one coil disconnected at a time so the misfire is only on one cylinder). Thats why a circuit breaker works good so your not going through fuses like crazy. Most auto parts stores sell resetable circuit breakers that you could use temporarily for testing.Ohm checking a coil is not always conclusive as it can still be drawing too much current even though it ohm checks ok.
Customer: replied 7 years ago.
My #5 cylender has ruened 3 coils now. The problem is defenetly with the ignition on #5. it is the coil that i replaced yesterday when I changed my plugs. the case was cracked and red stuff was in the crack. when i put the new coil in I put it in 6, and an old one in 5. then tonight i just went to the store to get fuses, a braker and one more coil. (just to have it). every time i pull the #5 coil it is very hot and cracked.

Wow this vehicle is just full of surprises.


Any oil or coolant in the spark plug well? Have you had the plug out? Any evidence of combustion gas getting past the plug either between the porcelain and base or around the threads/taper seat from being under torqued??

Customer: replied 7 years ago.
Not on 5. on 2 their was some oil around the top of the plug yesterday when i changed them. but not much. they all theraded in and got their 15ft-lbs
Customer: replied 7 years ago.
I also did a compression test on all 8 cylenders yesterday and go from 1 to 8. 170,165,180,175,170,165,165,170 what do you make of that?
Those all look pretty good to me..
Customer: replied 7 years ago.
any idea why the truck is ruining coils? This leads me to beleave that is what happend to my truck when i was driving.
No idea I have not run into this. If all the things I mentioned checked out good then I really don't know. Especially if that cylinder is not misfiring. I was thinking maybe the ground wire from the pcm to the coil shorting to ground but that would definitely cause a misfire.I am off to bed have a good night I will check in tomorrow
Customer: replied 7 years ago.
it is missfireing i feal it. but the truck dose not.
Any codes in the PCM for primary coil circuit on #5? Check the negative wire on the coil for continuity to ground with the PCM disconnected.Light green/yellow wire. Disconnect the coil and the pcm, one lead to battery neg one lead to light green yellow wire.What is the resistance? What do you mean you feel it but the truck does not?
Customer: replied 7 years ago.
the truck has not sent me one check engine light through this whole thing. but i feel it missing. i got to go to work, so when i get home ill look at the coil and its wireing
Customer: replied 7 years ago.
the truck has not sent me one check engen light through this whole thing. but i feel it missing. i got to go to work, so when i get home ill look at the coil and its wireing
OK sounds good
Customer: replied 7 years ago.
The neg side on the coil has no resistance with the negitave on the battery.
Thats what I figured was just hoping we might get lucky. There is a chance that the pcm coil driver for cylinder 5 is having a problem. Not having any primary circuit codes in the PCM is weird. If this was in my bay I would stress test all the coils to see if any of them are radiating high amounts of R/F. I would also perform a PCM coil driver test in oscilloscope mode to get a look at the driver waveforms as well as the secondary KV, and firing waveforms. Unfortunately all of these tests are proprietary in Fords IDS diagnostic scanner. I don't know what else I could have you check without having access to an IDS scanner. You might have to start thinking about getting it to a drivability tech at a Ford dealer. Did you ever check to see if the fuse blows with the coil disconnected and the engine running? The truck has to run for the fuse to blow correct?
Customer: replied 7 years ago.
yes it will run without the #5 coil. i think that is how i was doing my laps around my block after i got it all put back together (the dash and IC.) when I was talking about poor accelarition. Thank you so much Kenny. Is just changing out the pcm a option with a High percentage chance it could fix the problem?

That would be a 50/50 gamble IMO. It would need to be programmed also with an IDS.

Good luck to you Robert, I am always up for a good challenge, wish I could get my hands on it for a day or two. Its been interesting to say the least!


Take Care,