Unexpected engine failure (shut down) 1994 Ford 460 V8

This is a question for you folks with older (1994 vintage) Ford 460 V8’s. I had a strange event happen with my rig on my trip from Huachuca City AZ to Fresno CA. I was traveling north on I-5 from LA and just past Bakersfield my engine lost power and shut down. It’s done this once before on a long grade outside of Benson AZ. At the time I replaced the fuel filter and I also back-flushed a bunch of rust from my old filter, so I wrote the event off as a partially clogged fuel filter. This time I’d just gone over 4,148’ Tejon Pass an hour earlier with no problems and I was cruising along nicely on a flat stretch of I-5 with my cruise control set at 60mph when I began losing power. I quickly shut off the cruise control and worked the throttle. The engine started running smoothly again, but almost as quickly began once again to lose power. The engine finally shut down completely and I coasted off the highway. I sat for awhile and tried to start the engine, it barely turned over which was odd because before I’d left AZ I’d installed a brand new group 65 750 amp battery. As a test I beeped the car horn, which draws a surprising amount of amperage, and it beeped loudly. The entire trip my amp gauge was showing it to be charging. Anyhow, after sitting for 20 minutes I gave the engine one last crank and the engine fired up and ran great the last 100 miles to my destination.

So when I started this journey 650 miles before the problem in question I had:

I installed a new group 65 750 amp battery and a new battery cable. Up until this point the engine had cranked strongly. Within the past year I’d replaced the starter.

Within the past 1,500 miles I replaced the spark plugs, air cleaner, changed the oil and filter.

Within the last 650 miles I’d replaced the fuel filter.

The engine typically runs very well, the only consistent problem I’ve noticed is an occasional slight hesitation upon acceleration, and that usually occurs when the engine is cold. It’s such a minor thing that I haven’t given it much thought.

While I’ve owned and driven the machine it’s never over heated, it’s always shown excellent oil pressure, and the amp gauge always shows a slight charge while running (like you’d expect).

I’m a driver who’s normally well aware of what going on with my engine and this engine shut down came with no warning that I was aware of. Does anyone have any ideas what caused my engine to shut down like it did?

Steve

PS I'd suspect vapor lock but (1) I have fuel injection (2) the day before I'd driven under similar conditions through AZ in 100 degree heat.

Class A

rgatijnet1
Explorer III
May 05, 2014
Fuel pump.
fla-gypsy
Explorer
May 05, 2014
Since it dragged when restarting it sounds like overheating to me.
K_Charles
Explorer
May 05, 2014
Fuel pump
midnightsadie
Explorer II
May 05, 2014
two things and you mentioned one, you got rust from the filter. tells me your tank is rusty on the inside, pull that filter and look at it again. this rust could be geting to your carb. and the fuel pump, I
Teacher_s_Pet
Explorer
May 05, 2014
Fuel pump here also..runs ..stops.. cools down and runs again. Had this happen on our old '98 Intruder 460 in 2005 and our 2004 B+ 6.0 V8 Chevrolet in 20012. Both were in the fuel tank and both cost between $800-$900 to repair, after tanks removed, drained, cleaned, new pump with in-tank filter and partially filled with 10 gallons of premium fuel.
PUCampin
Explorer
May 05, 2014
Which battery cable did you replace? I had some wierd issues with my car a few months ago with intermittant no crank, slow crank, running ragged. In my case it turned out to be the main ground wire connecting the engine to the battery was loose at the engine. There were a couple other small wires grounding the the engine to the frame to help prevent ground loops, but they were not meant to be the primary current carriers. There was one 12AWG wire at the top I noticed had burned insulation. Some playing with my meter showed this wire was carrying over 20A when the engine was running, and over 100A when starting. A lot of resistance obviously, so I would get slow crank, no crank. The main ground went under the motor, and actually is secured under a starter bolt in my car. That bolt was loose. When I would drive around, it would contact more or less, carrying more or less of the running current, if the small wair was too hot and causing too much resistance the engine would start to run ragged, and depending on how much it was touching when I tried to start the engine, I would have various levels of success. But the battery still charged (through the smaller wire) and it did not affect any chassis electric like the radio or horn because the body to battery ground strap is separate. Once I tightened the bolt, all the issues went away. BTW, it took a while to troubleshoot and track this down, sometimes the right answer is the simplest. Good Luck!
96Bounder30E
Explorer II
May 05, 2014
rgatijnet1 wrote:
Fuel pump.

X 1000

What you describe is classic symptoms......keep the tank full and top off every 100 miles and you will not see the problem again........run it down to 1/4 tank or less on a hot day it will happen everytime.....
Geocritter
Explorer
May 05, 2014
For everyone’s discussion regarding my fuel pump, it sounds as if that might be it. One mile after the engine shut down I refilled my tank, it took 42 gallons, so my tank was more than half empty (the drive along I-210 and on I-5 over Tejon Pass had really taken a lot of gas, dropping my average mpg from 7.5 to 5.5mpg). I’d driven the rig in some mighty hot +100 AZ heat the day before but I never ran it below 2/3 full (cheapskate me filled up before I left AZ).

I’ll say right now, I really don’t want to replace the fuel pump. I replaced an in-tank fuel pump on a Dodge Caravan once (after a mechanic had failed twice to get it right) and it was one of the scariest jobs I’d ever undertaken. Even though I grounded everything, all I could think of was a huge fireball with me in the center!

PUCampin, I really appreciate your detailed description of your battery/starter problem, sounds very similar to the problem I’m having. The good news for me is that when I replaced my battery cable it left me with a spare cable the previous owner had moused on alongside the main battery cable. It’ll be a simple task to use it as a proper engine ground. It won’t cost me a dime and just might cure the problem!

I don’t know who did some of the mechanical work on this rig before I bought it, but if it was a professional mechanic the dumb SOB should be taken out and flogged!

Steve
Daveinet
Explorer
May 05, 2014
PUCampin wrote:
Which battery cable did you replace? I had some wierd issues with my car a few months ago with intermittant no crank, slow crank, running ragged. In my case it turned out to be the main ground wire connecting the engine to the battery was loose at the engine. ...
I was thinking along the same lines. A fuel pump or clogged filter will not make the engine crank slowly. If there is a poor connection, the engine heat will aggravate that. 1994 means EFI, so the computer can get confused with a poor ground connection.

In theory, if it was having trouble getting fuel, that could make it run lean and get hot. A hot engine will crank slowly, but I would assume that your engine temp was normal, so I'm really not suspecting a fuel delivery problem.
DavidP
Explorer
May 05, 2014
Sounds to me like vapor lock. Fuel pump is not normally intermittent. It is also very hard to turn over with vapor lock. Altitude can play a big factor in vapor lock.