Hi all, having an issue with my 01' V10 Excursion w/85K miles and this sub forum might help more than the Excursion specific area. My issue is an intermittent no start after driving for a bit. I will list the details below as it might be easier.

- Intermittent no start after short drive
- cranks strong and fires but stumbles and dies immediately - less than 1 second - this can repeat for several key turns but so far has always started eventually
- has never died while driving, once running and idling normally its like there is no problem
- has happened on 3 separate occasions now - separated by weeks not hours or days
- have replaced IAC valve, fuel pump relay, and battery (cleaned cable terminals also)
- when I have checked fuel pressure it seems normal - have not been able to get a gauge on it when it wont start
- I believe I can hear fuel pump prime but sometimes its too noisy out to hear clearly while turning the key

All the info I have found says to replace the IAC (I have done this) and then replace the fuel pump. At nearly $400 for a Motorcraft pump I would prefer not to chase the issue at that cost. I am wondering if I have an electrical grounding issue or similar?

Any help GREATLY appreciated!!

 

Can't help diagnosing your issue but Motorcraft fuel pumps can be found through eBay for not much more than $250 brand new. I went through this with my 5.4 earlier this year but didn't have time to wait for a new one to arrive---dealership does indeed charge upwards of $400.

 

This is the missing piece of data. Without getting a reading WHEN IT FAILS, you can only guess, at best.

FWIW, I'd guess the fuel pump also, but I'd probably do a test light on the pump power feed first to verify that it's not a control electronics issue before tackling the fuel pump. Mount the light where you can see it out of the corner of your eye whenever you start the engine.

FWIW, I've had excellent results with aftermarket pumps that I've bought from Rock Auto. I personally wouldn't spend up for a $300-400 Motorcraft pump assembly, I'd probably buy one of the $50 Airtex repair kits that includes the pump and the seals and strainers needed to rebuild the current assembly,

 

Next time it won't start, bang on the tank with a 2x4 a few times, with enough force to make the tank move, but not enough to break it The extra shock will get the motor brushes to make contact.

If you've ever had an under-voltage condition that made the engine hard to start, the extra amperage required to spin the fuel pump can cook the brushes and/or commutator and leave a dead spot. That little bit of shock from hitting the tank can make it start up again.

 

 

Fuel pumps:

you are correct $400 is too much for a pump. Might be ok for an assembly but you rarely need that.

1) walbro makes a pump that will put out 180 LPH and hooks into your assembly after old pump is removed. Cost $120 or so.

2) never use parts house pumps. Most are junk Chinese units.

3) I only buy walbro, denso, or bosch.

 

Had the problem again this morning. Had a short 10 minute drive and stopped. Tried to restart and stumbled and died. The second key turn same problem. Decided to turn the heater and radio off and low and behold it started. I am wondering about the pump drawing excess amps due to it failing. I ran errands a few hours later, making several stops, and the five times I needed it to start it did.

I agree checking pressure when the failure occurs is the only way to know if the pump is functioning. That has been an issue as the first gauge we tried didn't seal properly. Picked up a second gauge and now haven't been able to use it while the problem is present.

Just checked Rock Auto, looks like a full Motorcraft assembly is $300. A pump alone is under $100 but I would prefer a better brand. Walbro looks to be $113 online.

 

If that helped I'd be checking the voltage at the pump and if it is low work backwards until you get battery voltage

 

Update and hopefully end to this issue. I replaced the fuel pump with a Bosh assembly yesterday and truck starts stronger than ever. I do believe my issue was not the fuel pump itself but rather the plug connection at the pump. The connector at the pump had two of the male pins pushed in and thus I believe I had a bad connection. I did verify 12V at the truck side plug as well. This would explain the intermittent nature of the problem as well as low voltage not being adequate to start the truck. I now have a new pump and cleaned the connections to hopefully avoid the issue in the future. I applied 12V off the battery to the old pump and it turned on and ran easily.

If the problem returns I will certainly report back. Hopefully I wont have to

Thanks for all the help everyone!