01 F250 - 200K miles. Dealing with the dreaded crank, no start. When this first started, it was a cold morning. But the problem has continued for several days. Even on warm (65-70 degree) afternoons. Also noticed when this first happened that my oil level was very low. 6 - 7 quarts. Yeah, I'm an idiot. Immediately changed oil and filter.

WTS light comes on and goes off like normal. Service Engine light does not stay on, and no OBD codes.

Batteries are about 1 year old and have good voltage. RPM during startup is about 400.

GPR measures 12.5 at battery connection with key off. With Key on and Engine off, voltage measure 10.9 at battery connection and 10.9 at the post leading to glow plugs. GPR can be heard clicking when key turned on.

Disconnected ICP. Plug was oily. Truck would not start with ICP disconnected.

HPOP oil level also seemed a little low. Topped it off.

Got ohm readings from the connectors for the glow plugs today. All glow plugs on driver side measured 3.8 or very close to it. All glow plugs on the passenger side measured 1.8. Seems very unusual to me that they are so similar. I expected to find readings all over the place. I understand that these readings should be below 2 ohms. Is it time to replace all glow plugs? Just driver side glow plugs?

Am I missing something obvious? I'm a decent gas mechanic, but this is my first diesel.

 

In my experience readings are generally close together. If it was me, I'd just replace the driver side plugs for now, driver side is the easier side to do anyhow. Motorcraft plugs only.

 

Are you getting any smoke while cranking? Now sure oil level good? Fuel level? You might try plugging in block heater for an hour or just to see if any difference.