We lost the link to the actual manual a few years ago when they changed the format of the forum but we got it back, scrambled but we do have it. Here is a link to the index page.

https://www.thedieselstop.com/threads/97-15a-7-3l-di-turbo-workshop-manual.671689/?post_id=4716248#post-4716248

On your cold start have you tested your glow plugs? And while you said that you replaced the relay have you tested it?

Klhansen has a write up on testing the relay and the glow plugs, it is for a 99+. But the only real difference is that on a OBS the glow plugs are on the outside pins of the valve cover pass through connectors.

Hard/No Start? Check here first.

Thought I'd post this as a sticky thread now that cold weather is on us. How to check Glow Plug System To check the Glow Plug Relay (GPR) · Be sure the engine is cold, so that the PCM will tell the GPR to turn on. If the engine is hot, you won’t have as much time to check. (if oil temp is...

www.thedieselstop.com

 

...my truck....

What truck? You should put ALL your truck's details & history (as much as you know) into your signature(<-click that) so it shows with each post, as this page explains:

(click this text)


Phone apps don't always show signatures, so you may need to switch to a real browser in desktop mode on your phone, or just use a desktop/laptop computer. Put your location (nearest city) in your profile &/or signature, & upload an avatar of the truck. Not all its details are relevant to these issues, but you don't necessarily know which ones are relevant, so just put everything in now. The more pics you post (NOT in your sig) of the truck, engine, wiring, labels, & undercarriage, the more likely we can help you.

 

This link still works: 1997 F-250/350/Super Duty Workshop Manual
It's for 97 F250/350 trucks and will work for you (for the most part). It does not have the Electrical and Vacuum Troubleshooting Manual (EVTM) or Powertrain Control and Emissions Diagnosis (PCED) Manual volumes. Here is some stuff I've posted many times:

To check the injector/glowplug wiring: From each valvecover gasket connection's outermost pins (2 per connector) to ground you should get 0.1 to 2 ohms (indicates good plug and wiring). From each valvecover gasket connection's center pin to each immediately adjacent pin, you should get around 3 ohms (indicates good injector solenoid and wiring). You should not get any continuity from any of the outer pins to the 3 inner pins (indicates no shorts between injector and glowplug wiring). You should also get 0 to 1 ohms from each of the external harness connectors outer pins back to the Glowplug Relay's large terminal on the GP side (indicates good wiring from external connections back to the relay).

To check the glowplug relay (GPR), measure the voltage drop across the GPR's large terminals. While the GPR is active (up to 1.5 to 2 minutes after the key is turned to Wait-to-Start) put your meter leads on the large terminals (one lead on one large terminal and the other lead on the other large terminal). This measures how much voltage is being "lost" across the relay. A reading of 0.3V or more indicates a bad relay. Also, check the relay’s control wires (smaller wires) disconnected from the relay for battery voltage at the Red/Light Green striped wire and ground at the Purple/Orange striped wire (check both when the key is turned to Wait-to-Start).

These days I recommend downloading the FORScan/FORScan LIte app and getting a suitable ELM-327 OBD2 Interface Adapter as a fairly inexpensive diagnostic scanner solution. They make various types (cabled, Wi-Fi, Bluetooth, etc) for the various platforms that you might use for the app (computer, tablet, laptop, smartphone, etc.). You will then be able to read/clear trouble codes, run various available tests (KOEO, buzz, cylinder contribution), and read/record live data for analysis. I use FORScan Lite on an iPhone 13 with an OBDLink MX+ bluetooth adapter (not the cheapest adapter out there, but I wanted a decent one).

Cheers!

 

Thanks for the link! I’d check glow plugs and test the relay voltageFORScan helps a lot with diagnostics.

 

Yes, the link for the 1997 F250/350 is still valid. Thanks for sharing. You’ve been a big help to me right now.