1. Refuel: First and foremost, add diesel fuel to the tank. Don't just add a little; fill it at least halfway to ensure you have enough to work with.
2. Check the Fuel Filter: The fuel filter is a common culprit in priming issues. If it's old or dirty, it'll severely hinder your efforts. It's best to replace it before proceeding, or at least thoroughly inspect it.
3. Manual Priming Pump (If Equipped): Many 1988 F350s had a manual priming pump on the fuel filter housing. This is your best friend. Repeatedly pump this lever until you see firm resistance and feel a consistent flow of fuel. You should see bubbles disappearing from the pump as the air is purged.
4. Bleed the Fuel System: Even with the priming pump, air can remain trapped in various parts of the system. There are several points you'll need to address:
* Fuel Filter Housing: Some air might still be in the filter housing even after pumping.
* Injection Pump: This is the heart of the system. On many 7.3 IDIs, you'll find a small bleed screw (often a hex-head bolt) on the injection pump itself. Loosen this slowly, crank the engine (with the key), and tighten it once fuel comes out without bubbles. Be prepared for some diesel to spray out. It's crucial to do this slowly to avoid damage. *Look up a diagram for your specific model to find its exact location.*
* Injector Lines: Less common, but sometimes individual injectors might have bleed screws. Check a service manual if you suspect this might be the case.
5. Cranking the Engine: With the bleed screws tightened, try cranking the engine over. It might take several attempts. Do not crank for extended periods without pausing. This can overheat the starter and damage the battery. Give it short bursts, maybe 10-15 seconds with a few seconds pause between.
6. Listen and Observe: As you crank, listen carefully. You might hear the engine try to catch. If you're lucky, it'll fire up relatively quickly. If not, repeat steps 3-5, paying close attention to any areas where air might be trapped.
Important Considerations:
* Glow Plugs (Important for cold weather): If it's cold, your glow plugs are crucial for starting. Let them cycle completely before attempting to crank.
* Battery: Ensure your battery is fully charged; cranking takes significant power. If your battery is weak, charging it or jump-starting it is essential.
* Service Manual: A factory service manual for your specific 1988 F350 7.3L IDI is invaluable. It provides diagrams and precise instructions.
* Professional Help: If you're not comfortable working on your fuel system, it's best to have a mechanic handle it. Incorrect priming can damage the injection pump, a very expensive component.
Remember, patience is key. Priming a diesel engine takes time and persistence. If you've tried everything and it still won't start, seek professional help.
