1991 Ford F350 - Answered Questions & Fixed issues

Make sure the connections are Clean and tight on the solenoid first. The solenoid itself has rather small studs
holding those big cables. If checking those connections does not solve the problem then you need to crawl under the rig and check the cable on the starter if tight the starter will need to be replaced.

Under hood

You’re missing one part of your problem. Be sure to check your grounds.

Have you ever had the catalytic converter changed? sounds like its melted and restricting the exhaust from getting out of the engine.

diesels are hard to start if the crank speed is too slow--- fully charge the batteries the injector /s /tips need replacing---squirting not atomizing there is air in the fuel system

Sounds like a lean misfire condition. Have you run a fuel pressure test? Should be 55-60 lbs. If pressure is ok during idle and reving, Ttry disconnecting MAF and see if any difference on accel.

Usually a leaking injector or a failed fuel pressure regulator.

Really no way to do this. A micrometer is usually part of every store that sells rotors. Even if they do not turn rotors, they still need to know if yours are safe.

Do your dash lights work if not you have a blown fuse the fuse controls both dash and running lights if this was helpful please leave good feed back

There is a check valve in the fuel pressure regulator that maintains fuel rail pressure when the engine is not running. Check it first before going after a leaky injector.

www.ford-trucks.com/forums/952700-belt-diagram-for-7-3-a.html

your not mentioning if this is gas or diesel allthough im hoping it's a diesel being a f350 (gas is not so practical at this size truck) anyway if it's a diesel and you have a hot hard to start problem it's most surely your injectors getting stuck open and draining off your fuel pressure it only takes one stuck open to drain off all pressure but a 91 should have em all replaced at same time any good diesel mechanic would know how to confirm this with a few simple tests

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Most likely it's a stuck / faulty thermostat.

The two brass fittings are for the automatic transmission fluid cooler.

Some models simply don't use a drain valve.

Behind the glovebox is the heater box (the plenum) mounted in a hole in the plenum is a resistor. There are screws holding it in. The part controls the fan speed. Replace it by locating the wires that go to it and removing the item and the plug and put in a new one. If you get one from an autoparts store, you will know what it looks like.

What size engine do you have?

Check for power on the glow plugs. You have two fusible links on the passenger side by the stater relay and a plug going over to the engine. These plugs get intermittent and that can cause your hard starting; the glow plugs themselves maybe burnt off. I've seen this happen with the other Ford diesels in our tow trucks!

ON MY 91 DID THE SAME THEIR WAS A INLINE FILTER CHANGED AND NEVER DIED AGIN

1991 ,you sure this is so old the speedo cable is no way related to the gearbox on such a old vehicle ,now these 350 things are a 7.4 litre and i serviced one last week a 1989 camper van version here in spain and the access for the spark plugs leaves a lot to be desired ,So anyway this one of yours has had its day and well past its sell by date plus its not politicaly correct anymore to have such a CO2 pollutant machine ,well enough of trying to wind up my american cousins so look around for a replacement vehicle as this will be a cheaper alternative ,now how about a nice mercedes vito diesel manual or better still a ford transit diesel with a manual gearbox and the amount of fuel costs you will save will pay for the vehicle .

Have you been in any type of a wreck? If so the inertia switch is located in the circuit between the fuel pump relay and the electric fuel pump(s). If you have been in a significant impact the mechanism inside the switch will cause the switch to open the electrical circuit, shutting off power to the fuel pump as a safety precaution. The inertia switch is in the cab on drivers side, up against the firewall, to the left of the brake pedal or behind the right kick panel. I would suggest buying a new one because it is not something you can reset.