Several months ago, my truck begins having starting issues. Intermittently, the truck will not start, even though it cranks fine. I have done the following:
- checked inertia fuel switch. Okay.
- checked connections under hood for corrosion. Okay.
- checked fuses & start relay. Also swapped relays with no luck fixing the problem.
- sprayed water at various locations under the hood and bed, since the problem occurs more often when raining. No luck stressing the problem.
- changed fuel filter a couple weeks ago. No luck fixing the problem.
- changed battery over the winter (due to my 8 year old battery was becoming weak). No luck fixing the intermittent starting problem.
- changed the starter a month ago (since the truck stopped cranking). No luck fixing the intermittent starting problem.
- Installed a fuel pressure gauge on the fuel rail.
- Tried banging on the fuel tank with a rubber mallet. No luck fixing the intermittent starting issue.

When the truck refuses to start, the fuel pressure reads 0. Sometimes I can wait 5-10 minutes, and it will start. The truck runs fine after starting.

Sometimes waiting 5-10 minutes will not solve the problem (fuel pressure remains 0). Then, I hook my battery charger to the battery, and the voltage climbs from ~12.5V to 14.7V. The fuel pressure climbs to 30, and the truck starts.

I'm apprehensive to change the fuel pump, since it seems like more an electrical problem than a pump problem. Does someone have advice or a diagnostic test that will tell me the true problem source?

Thanks.

 

Have you checked your fuel pump relay? It may be sticking and not transferring voltage to the pump. I believe there are 2 relays in play when activating the pump. I believe the PCM relay has to activate before the fuel pump relay will. And the pump won't stay on long when you first turn the key on. It has to get a good signal from the crank position sensor to continue pumping fuel.

 

check the pink and black wire that goes to the fuel pump.you should get 12 volts for a second or 2.if notcheck the dark green and yellow wire at the inertia switch.also try disconnecting the crankshaft speed sensor at the pass. front of the engine.its between the ac comp. and front cover.

 

From what you describe it sounds like your fuel pump. You need to check not only fuel pump pressure, but fuel volume as well. You can use your pressure tester to check volume. You put the hose on the pressure relief valve in a jar. With the engine running open the relief valve and let the fuel flow into the jar. Do a 30 second count then stop. You need at least 1 pint in 30 sec. You can also do a current draw test on the pump motor with a clamp on and a DVOM or DSO.

 

Thanks for the guidance. Last night, the truck refused to start, right after ~ 15 minutes of running. Fuel pressure was 0, when it would not start. I grabbed my voltmeter and started with your suggestions.
Redwood and I-m tech:
- Incorrectly, I checked the black & pink wire in the fuel pump harness by the fuel tank. No voltage on this wire. Fuel pressure remained 0. I had not realized my mistake at this point (I checked the wrong wire).
- Moved on to the green & yellow wire by the inertia switch. No voltage while it was connected to the switch...6.75 volts when disconnected from the switch. Tried again, no voltage while connected to the switch. Then I triggered the inertia switch, and read 6.75V while the harness was connected to the switch. Reset the switch and no voltage on the green/yellow wire while the harness was connected to the switch. Fuel pressure remained 0 during this process. Note that I checked a black and pinkish looking wire on the other side of the switch harness connector, and it read 12V.
- Moved to the crankshaft speed sensor, I think. I have a photo of the connector, but I can't post photos to this site.<link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CCHRISS%7E1%5CLOCALS%7E1%5CTemp%5 Cmsohtml1%5C01%5Cclip_filelist.xml"><link rel="Edit-Time-Data" href="file:///C:%5CDOCUME%7E1%5CCHRISS%7E1%5CLOCALS%7E1%5CTemp%5 Cmsohtml1%5C01%5Cclip_editdata.mso"><!--[if !mso]> <style> v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} </style> <![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--><!--[if gte vml 1]><v:shapetype id="_x0000_t75" coordsize="21600,21600" o:spt="75" oreferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f"> <v:stroke joinstyle="miter"/> <v:formulas> <v:f eqn="if lineDrawn pixelLineWidth 0"/> <v:f eqn="sum @0 1 0"/> <v:f eqn="sum 0 0 @1"/> <v:f eqn="prod @2 1 2"/> <v:f eqn="prod @3 21600 pixelWidth"/> <v:f eqn="prod @3 21600 pixelHeight"/> <v:f eqn="sum @0 0 1"/> <v:f eqn="prod @6 1 2"/> <v:f eqn="prod @7 21600 pixelWidth"/> <v:f eqn="sum @8 21600 0"/> <v:f eqn="prod @7 21600 pixelHeight"/> <v:f eqn="sum @10 21600 0"/> </v:formulas> <vath o:extrusionok="f" gradientshapeok="t" o:connecttype="rect"/> <o:lock v:ext="edit" aspectratio="t"/> </v:shapetype><v:shape id="_x0000_i1025" type="#_x0000_t75" style='width:431.25pt; height:323.25pt'> <v:imagedata src="file:///C:\DOCUME~1\CHRISS~1\LOCALS~1\Temp\msohtml1\01\cli p_image001.jpg" o:title="IMG_0970"/> </v:shape><![endif]--><!--[if !vml]--><!--[endif]--> Disconnected what I think was the crankshaft speed sensor. Fuel pressure remained 0.

At this point, I questioned my voltmeter ground on the black & pink wire by the tank, so I started again. After verifying a good ground, I checked the black & pink wire, and it had no voltage. Fuel pressure remained 0, and the truck would not start.

I hooked up the battery charger, and after about 5 minutes (battery voltage ~14.8V), I tried starting it again. Fuel pressure rose to 30, and it started. I had the voltmeter connected during this, and then I realized I had the wrong wire leading to the fuel pump! *#!@&^% Hooked up the PINK & BLACK, and it read 13-14V while running. Turned the engine on/off several times, and the voltage moved from 0 to 12+V, when going from off to on.

As luck would have it, the truck has started fine since. I am waiting for another "no start" moment, in order to catch the PINK & BLACK wire voltage.

Eallenboggs: I will try the fuel volume check, once I plumb a pressure relief valve & hose. My current fuel pressure tester does not have a pressure relief valve. I might try removing the gauge, holding my finger over the hose end, have someone start the truck, and the let the fuel flow into a container.

To add to my string of luck with vehicles, the truck started running rough over the weekend. Felt like it was missing on one cylinder. Autozone pulled the code tonight, and it was P0308...#8 misfire.
Now I have 2 issues to solve. Trying to smile at this point in time.

 

You lucky you got P0308. Most of the time Fords misfire stategy threshold is so high you have driveability issues without ever getting a misfire DTC. You need to change #8 COP as these COPs are renoun for failing. #8 is the hardest to get to on Bank 2. If you haven't done a tuneup on this thing I'd pull all the COPs on that side(pulling fuel rails make the job easier and don't forget to change the "O" rings while the injectors are out) and change all 4 plugs on Bank 2 and #8 COP. If you can get the bolts that hold the bed on removing the bed is the easies way to change the fuel pump. You won't have to drop the tank that way. Clean all the trash and debris away from the top of the tank, remove the connectors and spin the big ring off. The pump will lift right out. Don't forget to change the strainer and lube the "O" ring with some dielectric grease.

 

eallanboggs: Thanks for the tips on changing the pump. My truck does not have the COPs, so I will pursue spark, fuel, air for cylinder #8...


Update
The truck finally decided to refusing starting again. I took the following voltage measurements, when the truck would crank, but not start:
- Battery voltage, 12.6V (no load)
- Fuel pump, 10V for 1 sec , then 0V (w/ key on, but not cranking)
- Fuel pump, 9V (w/ engine cranking)
- Inertia switch, 11V for 1 sec, then 0V (w/ key on and inertia switch in normal operating position)
- Inertia switch, 11V for 1 sec, then 6.75V (w/ key on and inertia switch in triggered position)

With Crank position sensor unhooked:
- Fuel pump, 11V for 1 sec, then 0V (w/ key on, but not cranking)
- Fuel pump, 0V (w/ engine cranking)

Note: The fuel pressure remained 0 during these measurements, and the truck would not start.


Then, I installed my battery charger and reinstalled the crank position sensor:
- Battery voltage, 14.6V (no load)
- Fuel pump, 13V for 1 sec, then 0 (w/ key on, but not cranking)
- Fuel pump, 10-11V (w/ engine cranking)
And, the fuel pressure rose to ~30, and the engine cranked & started.

My next steps are to a.) have my new battery load tested, since the fuel pump only had 9V while cranking without the aid of the battery charger, and b.) change the fuel pump, since it works with high enough voltage

Does anyone know the voltage spec. for a fuel pump? Should it work with 9V?
Any other suggestions?

 

Do you know what reserve capacity is? It looks like your battery doesn't have any either because it is discharged or has a problem and needs to be replaced. Your starting point is a good battery with clean tight connections at the post/teminal junction. Without that all bets are "OFF" and you can throw all your test results out the window. Once you get a good battery in there you can start to measure fuel pressure and volume. The easiest way to verify a fuel supply problem(once you get a good battery) is to spray a little starter fluid in the throttlebody(plenum removed) while you have an assistant crank the engine. If it starts with the help of the starter fluid you have a fuel supply problem. If it doesn't go fish. I don't see the connection between your tests of the fuel pump and crank sensor. Do you think they have feedback to each other or something that would cause you to do that test?

 

The PCM has to see a signal from the crank sensor before it will activate the relay that turns on the fuel pump. Otherwise, the pump comes on for a sec to pressurize the system when you turn the key on then it shuts right back off.

If the fuel pump works with high enough voltage, ie with a host battery hooked up, then it sounds to me like all you need is a good hot battery and be done with it. That'll probably take care of your problem...

 

Time to look at that crank sensor on Alldata. Now I want to see that feedback circuit. If he doesn't have a CKP pulse he doesn't have spark of fuel. That hurts big time. I think I'd hook up the scan tool and watch the CKP PID. Maybe that's been his problem all along notwithstanding the bad battery.

 

I wasn't trying to imply the CKP was bad. His test proved it was good. Considering the voltage drop during cranking, there may not be enough juice to get the fuel pump working. Since he is getting voltage to the pump, albeit low, I'd assume the relays are good also. 12+ VDC = running truck, 9V = not. Have the battery tested. I bet it comes in weak. How old is the battery that's in it?

 

we had issues with the crank shaft sensor connector at the dealership.found that you needed to remove each wire at a time.solder the wire to the terminal and retention the blade on the inside of the terminal.sometimes the blade on the inside of the terminal would get lazy and not make good contact with the sensor intermitatlly.just a idea.you really need a scan tool that can look at the rpm pid to tell if this is your issue.

 

Lazy is a term usually applied to old, high mileage 02 sensors not terminals on a CKP connector. Better to say lacks continuity. Chrysler had such a big problem with the connector terminals going to the solid state relay for the electric fans they made an upgraded connector available at their parts counter. The teminals would get loose and start to arc because a fan motor is high current which a CKP is not. If a CKP connector is intermittent the results are going to be much worse than a loose connection at a fan relay. You can also see the CKP pulse using a low current clamp on probe connected to your DVOM. I've corrected crank, but no starts on Ford and Lincolns by just pulling the CKP connector and spraying them with electrical contact cleaner. Years of dirt and smegma can result in a poor connection.

 

i was just stating what ford engineers had us do.i repair cars im not a english major.they didnt tell us that we had to use specific words in this forum.

 

Thanks for the guidance. Work, a sick family, and traveling out of town has hampered my progress. I hope to regain momentum this weekend.

My battery is 8 months old, and it's a Duralast Gold 65-DLG (850 cold cranking amps, 1000 cranking amps). My last Duralast Gold battery lasted 8 years / 80K miles, so I had high hopes for the new one. I will have it load tested this weekend.

If that passes, then I plan to check the fuel pump resistance, as a friend recommended this from a similar experience. If the resistance looks high, then I might try the bed removal approach to remove the pump. I started this several weeks ago, and the first bolt snapped on me (one of the bolts that retain the bed tie downs in a flareside. I must remove the tie downs to remove my bed liner). Due to the broken bolt, I am reconsidering dropping the tank, as I have 7 more of these bolts to remove...and removing snapped bolts from rusty threads is not my favorite hobby...

I will try electrical cleaner on the CKP. How about some dielectric grease? The connector was easier to remove than I expected, once the plastic tab was out of the way, so the connection might be a complicating factor.

I will post again over the weekend.