95 F-150 4x4 5.8L.

Friday my wife was towing the horse trailer from a vet appointment. 1/2 mile from the barn she ran over something in the road that banged up under the front of the truck, and the truck stalled. (We later retrieved the "something" that was half of a leaf spring that fell from another vehicle). She got it restarted but the stalling persisted and it died (would crank but not turn over) 1/8 mile from the barn. Inertia switch was not tripped, everything looked good, but the battery was getting a little tired from so much cranking. Fortunately it was close enough that we towed the whole rig in with a tractor and chain.

Nothing obvious was damaged under the truck. No leaks, no marks from the leaf spring, belt is good and radiator looked fine.

Since it was dark and we are only boarders at this barn, I pulled the battery for charging and came back the next day. I did a KOEO test, and it came up clear in the first set but there was a code in the second set (stored codes). As is usually the case I couldn't get the numbers right the first time and when I went to review them the stored codes were gone. Whoops.

Tried starting it, and it started beautifully like nothing had happened. Maybe it was flooded when it wouldn't start(?)

Now I'm puzzled - this truck has been pretty reliable but stalling while towing a horse is not acceptable. We're going to drive the truck without trailer some this week to see if we can shake down any misbehavior.

I'm looking for ideas of why that leaf spring made the truck stall, and what damage I should look for to repair to ensure this doesn't happen again. Thanks.

 

Maybe it smashed a the pressure fuel line closed and it reopened over night.

 

Update:

I took the truck home from the barn today (4 mi drive) and it stalled right at the stop sign before my street. It is a bit of an uphill, FWIW. Couldn't get it restarted, so I left it nearby (thank goodness for downhills).

I also noticed that the front tank went from "F" yesterday to above "F" today. This truck has never exhibited the crossover problem before.

I will inspect the fuel lines for certain, this is a good idea. I might also try to install a fuel pressure gauge in line and let it run in the driveway until it stalls.

Dave

 

Sounds more like you got the wiring with the spring.
An open wire to the fuel gauge will make it go past full.

 

I couldn't get it restarted to get it all the way home.

I get no KOEO codes, and one stored code 22 (MAP/BP sensor). Truck just cranks and cranks. I see nothing damaged near the MAP sensor, and the wiring for the map sensor runs all the way around the top of the engine bay well away from where debris could have touched it.

I also noticed that the 30A fuse at position Q was burnt, replaced it to no effect. Based on the manual I think it's for the trailer battery anyway.

I crawled around underneath and found nothing damaged. The fuel lines and wiring were still tucked away, no leaks, nothing obvious.

I sure hope this doesn't take an electrical degree to solve. Ford's electrical connectors aren't my favorite and the wiring diagram I have on CD is just terrible to navigate.

 

Did you put the fuel gauge on it yet?
If so did you ground pin #6 of the EEC self-test connector wit the key on when you did the test?

Here is a diagram I made, maybe you can read it better.




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Thanks for all the help subford. Funny, as I google for more info your name is always in the responses.

Well I'm a *******. The CM code was 211, PIP sensor. After googling the PIP sensor it matches the symptoms.

Given that the truck took a wallop from the underside, could the distributor have been damaged? Maybe it's time to buy a whole new distributor, after all it's been 175k miles and as far as I know only the cap and rotor have been replaced.

I was reading the disconnecting the SPOUT jumper might make the truck run. That would be great so I can drive it that last 1/4 mile home. Will that help?

 

No not if the PIP sensor is bad.
Disconnecting the SPOUT jumper will only help when you have a bad computer.
I do not think hitting the spring did anything. They just do it own there own sometimes.

 

OK, spent a little quality time down the street with the truck. It still cranks, no start.

I checked for fuel pressure by jumpering the FP Relay Gnd in the diagnostic connector to chassis ground. Key on, it took 5-10 sec to reach 41psi. It stayed above 40psi for at least a minute after keying off. So assuming I did that correctly I have fuel.

I then checked for spark at one of the plug wires. I used one of those adjustable-gap spark testers set for 1/4" gap and the plug wire that runs to the front/driver's side cylinder. No spark when I cranked. So then I tried again using the wire running from the ignitor to the center of the distributor. No spark when I cranked.

I will dig into the manual I have on CD, but if anyone knows what to make of this I'd appreciate some pointers.

Thanks,

Dave

 

Did you read my post above?

 

Yes I read all of your posts. Clearly there is something you recommended that I do that I have not, so please point to the particular post I should review.

I believe I've established that there is fuel and but spark. So the fuel system wiring is not at fault. There is a PIP sensor code. Based on what I'm reading, the ICM needs PIP signal to generate spark, so that puts PIP function at the top of the list.

If indeed I should investigate PIP sensor function, then it appears I should 1) verify power to the ICM, 2) verify signal voltage coming from the PIP to the ICM while cranking, 3) Verify SPOUT signal, 4) verify power at the ignition coil.

David

 

Sounds like your on the right track.

 

I'm following the PIP troubleshooting sequence in the Haynes manual, and I must sadly admit I got stuck when it was time to disconnect the PCM connector.

Does the 10mm bolt work as a jacking screw, or should I loosen it all the way and pull on the connector?

It's a huge connector so I wasn't willing to pull hard on it and break something.

David

 

Back the screw out until it gets a little hard to turn and then wiggle the connector and then back the screw out a little more and wiggle the connector as you pull out on it a little and it will finally come out.

 

Yea the bolt will withdraw the connector as you unscrew it, then just finish pulling it off the last little bit by hand. Won't be on by much when the bolt is all the way out.