460 Ford Forum banner
1 - 13 of 13 Posts

·
Registered
1994 F350, 1978 F250
Joined
·
10 Posts
Discussion Starter · #1 ·
The truck is a 94 F350 with a 460/zf5. The TFI is mounted on the fender, not the distributor.

Spark plugs, wires, cap and rotor are all new. Battery is in good health and so is the starter. The fuel filter is new. The coil is new. When I bought the truck is was hooked up to a Jacob's box with a Mallory coil. I pulled that out and installed a regular coil.

The issue is, intermittently the truck will need to crank long periods of time before firing. This usually only happens when the truck has not ran for a few days. If I start it every day it starts fine, if I don't touch it for a few weeks it will start fine. But that window in between is when the issue occurs.

I dropped in a new distributor Friday because after all my googling that's what seemed like the most likely culprit, today the issue persisted. I don't like to throw parts at an issue, and I'm at a total loss here.

From this point I think I'm going to run a fuel pressure gauge on it and spend some quality time probing sensors with a multimeter.
 

·
Registered
Joined
·
433 Posts
Have you ever tried to cycle the key for a few seconds a few times when you think the issue may occur? I know you said if it sits a few weeks it's fine, but is that set in stone? Sometimes the check valve in the fuel system goes bad, and it can take a little while pressurize the fuel rails, resulting in extended crank times. Cycling the key will prime the system up.
 

·
Registered
1994 F350, 1978 F250
Joined
·
10 Posts
Discussion Starter · #3 ·
Have you ever tried to cycle the key for a few seconds a few times when you think the issue may occur? I know you said if it sits a few weeks it's fine, but is that set in stone? Sometimes the check valve in the fuel system goes bad, and it can take a little while pressurize the fuel rails, resulting in extended crank times. Cycling the key will prime the system up.
I have sort of tried that. I don't really know when it is going to happen, so I haven't done that exactly, because there's always the initial crank. I do always listen for the fuel pump and make sure it fully primes before the initial crank.

I have hit the valve on the fuel rail to make sure it's pressurized. I plan to throw a gauge on it and monitor.

I do park the truck for the winter and every spring it fires right up like new.
 

·
Registered
1994 F350, 1978 F250
Joined
·
10 Posts
Discussion Starter · #11 ·
Started the truck today after work. Last time the truck was ran was Saturday, so it say for 2 days.

Temp in low 50s, front tank selected, cycled key 5 times listening to the fuel pump prime. Cranked it and it turned right over and fired smooth in 3 to 5 seconds. High idle was normal and regular idle was also normal. Driveablity was good.

I have not yet picked up a fuel pressure gauge to run on it.
 

·
Registered
1994 F350, 1978 F250
Joined
·
10 Posts
Discussion Starter · #12 ·
The saga continues!

Today I started the truck for the first time since I last updated this thread. I did the same procedure of cycling the key 5 times then cranking.

As I was listening to the fuel pump I noticed it was running continuously and not priming and shutting off. I know it has done this in the past when cycling the key but paid little attention to that detail.

I had the front tank selected at first and experienced the crank no start after the 5 key cycles. I then switched the the rear tank. I noticed the same continuous running of the pump and did some experiments leaving the key on longer and longer. Still getting a crank no start. I also noticed i could hear fluid running as a light trickle. Switching back to the front tank trial and error process the same gave the same result.

At this point I decided to stop trying because I have other stuff to work on today and didn't want to kill my battery and not have time to deal with it.

I shut the door to the truck and heard a loud click in the fuel tank area. I don't know what it was but thought maybe it was something to do with the fuel pump. I gave it one more shot cycling the key (front tank) the pimp primed normally. I did not re-cycle the key just cranked from there and SUCCESS! it started correctly without issue.

Thanks everyone for pointing me in the direction of fuel vs spark. I'll research that end of things going forward.
 
1 - 13 of 13 Posts
Top