I recently purchased a 1996 F-350 4x4 crew cab. Texas truck with 42k miles. Picked it up cheap from a friend. The truck ran great then all of a sudden wouldn't start. When I turn ignition, the speedometer needle drops below zero. I have no power to solenoid, no power to fuel pump. Is it possibly the ignition switch? Does this sound like a short?

 

Automatic or manual transmission? What engine?

So it does not crank with the key? Do you hear a "click" when you turn the key to START?

 

Inertia switch? Should be behind the passenger side kick panel.

 

This only kills power to the fuel pumps, it has nothing at all to do with the starter...

 

I stand corrected. Just seen a lot of guys trip the inertia switch when they get a new 4x4. Gotta make sure the 4WD works, right?

Edit: Also, check neutral safety switch and the wires going to it.

 

It has a 5.8 EFI, automatic. When I turn key there is no click to solenoid. But when I jump poles on said solenoid, the starter turns. On a multi meter, when I turn key, there appears to be a complete negative draw on the battery. I will check inertia switch in the am. Thank you for your input. Phil

 

So by "negative draw", do you mean that the battery voltage is getting drawn down? Sounds like the starter relay is somehow pulling down the voltage. You could confirm by putting 12V directly to the small trigger terminal on the relay. If the engine still doesn't crank, and you get the same drop in voltage, then the relay is the suspect. If it DOES crank, then that suggests the relay is good, and the problem is "upstream" - ignition switch, neutral safety switch, wiring, etc. Might be worth trying to start it in neutral.

If you're just seeing some accessories go dead when you turn the key to START, don't misinterpret that as a major draw. Just look at a diagram for the ignition switch sometime. Lots of different contacts with lots of different closed/open combinations based on key position. Several things that depend on the key go OFF while cranking. That's intentional; it avoids diverting needed power from the starter circuit.

 

I checked for voltage at the starter relay when turning ignition, no voltage. Where might I find the neutral safety switch? Is that the one on the brake pedal? Can I jump either to check to see if they are bad? Thank you!

 

Would it be worth the effort to pull the plug at ignition and check all leads to see if any are grounding out? Is there a link here where I can locate proper wiring diagrams?

 

Asked and not yet answered - automatic or manual transmission?

Nothing on the brake pedal affects starting, since obviously you don't need your foot on the brake to start the truck.

 

Do any of the dashboard lights come on when you turn the key on? Check engine light? Brake light?

 

automatic, only think that lights up on dash is the digital mileage, when key turned, speedometer drops below 0 and mileage goes out.

 

this was not my truck before so nothing is obvious to me in this scenario. I appreciate the foundation of knowledge and that is why I am here seeking help. Thank you.

 

Well, I, for one am lost too. Maybe start again at the top and describe exactly what is happening here. We know you have a 1996 F350 with a 5.8/E4OD. Nice truck by the way. Sounds like low mileage, ran fine and now will not run.

Put away all speculation about shorts and negative draw on the battery. It would appear that when you turn the ignition on, the odometer will light up, but when you turn the key to crank, nothing happens except the odometer light goes out. You can crank the engine by jumping the solenoid under the hood. So far correct?

There is a lot we do not know about your truck that would be relevant. I think the fact you can crank the engine by jumpering the solenoid confirms you have a charged battery and the primary cables and connections are OK. The statement about "no power to the solenoid" is misleading as there must be power at the solenoid if you were able to crank the engine by jumpering it. So, what is NOT powering up? Headlights, radio, turn signals and wiper? All of this could be relevant because we can then determine if you ignition switch is working and receiving power.

If you turn the ignition on and jump the solenoid under the hood to crank the engine, does the engine start? When you jumper the solenoid, this could be done in two ways. You can jumper across the large terminals, which bypasses the solenoid entirely, or you can test the solenoid by jumpering the small terminal to battery +. Either way, the engine should crank.

The fuel pump will not receive power without the engine running or cranking. This can be tested at the EEC test connector which is also where you will go to check for engine codes, but we are not at that stage yet.

Right now, your problem could have many causes and a systematic approach is required to narrow down the field to what will likely be one simple cause.

 

Try starting it in neutral. If that doesn't work, try (two-hand tricky maneuver) moving the shifter from Neutral toward Reverse and toward Drive, WHILE holding the key in START. If any response, the neutral safety switch (on the tranny) needs to be adjusted or replaced.

Since the odometer display is coming on with key in RUN, that's some good sign; there's power through the RUN circuit of the ignition switch.

Do you hear any click from under the hood while turning the key to START?

Odometer going blank is expected. With key in START, PSOM is not energized.