EDIT the word "isn't" is not supposed to be in the title. Wont let me edit that though.

My 2003 F250 has been getting pretty hard to start in cold weather.

No issues starting at 0* oil temp a couple months ago. Obviously I could tell the truck didn't like it, but it still started just fine, no romping, etc. I usually plug it but was traveling, no outlet available.

Day before yesterday the oil temp was 17*... took 5 or 6 cranks before it finally started. Stumbled around on a few cylinders then evened out.

Leaving work right now (truck is warming up), oil temp 22*, let glow plugs do a full cycle (LED mod), then hit the key back over and gave them an extra 30 seconds. Started on first try but a lot of stumbling and rough running for the first 30 seconds or so.

My GPR must be working since my LED is lit up... so I'm thinking the likely cause is some of my glow plugs have gone bad? Truck only has about 145k on it.

Anything else I should double check before I replace them? Running Rotella 5w40 synthetic (which I hate, but the store was out of everything else). I usually run the Delo 5w40 synthetic, and that's what was in it when it started fine in the super cold temps.

Unlikely an oil problem though. And before anyone asks, I dislike the Rotella because my truck burns it really fast. Like 4-5 quarts per 5k miles. If I run the Delo, or any other 5w40 synthetic oil that I've tried, I burn 1, maybe 2 quarts depending on what the truck has done.

 

Problem 1:

When you go to edit the post, there is a button "Go Advanced" in the lower-right corner. Click that, and the title field will come back up for editing.

Problem 2: Classic glow plug symptoms. It sounds like you'll be turnin' heads (VC bolts). You mentioned the LED mod - is that connected to the GPR input or the GPR output? It can't hurt to throw a meter across the output to make sure the contacts aren't burnt.

 

What is your battery voltage when the glow plugs are on? And off?

 

I've been having the exact symptoms this year, just with slightly warmer temps. Lowest so far here the "south of Boston region" has been -4*-0* ambient.

My GPR LED (tied to the output post) is showing a functional GPR, also, I took current readings at the GPR output cable and saw an initial draw of 160a - with a constant draw of 80a. Voltage drops to around 11.2v while the GPR is energized.
I assume those numbers indicate an average draw of 10a per Glow Plug...???

5-40 synthetic here too.

(sorry for the slight hi-jack... errr..... (more like coat-tail ride)

 

The GPR light indicates there is about 1 amp or less illuminating the LED or bulb. "Your glow plugs are on - providing the system is functional) It does not ensure the Solenoid is functional for the Glow Plugs to operate.

11.1 VDC on the gauge/DMM is accurate providing the Batteries prior to test were at 12.6 VDC (1.5 VDC Drop). That's about the maximum drop you'll ever want to see in the GP Circuit.

80 AMPS is about correct providing each is drawing 10 AMPS. But, the only way to be certain each is receiving the average of 10 AMPS is to OHM each GP to ensure they all are within the specification parameters.

90pioneer: Glow Plug Testing in in your future. A simple OHM test will identify failing or, failed GP's.

Also perform the drop test described in the previous paragraph to ensure you're getting maximum Voltage / Amperage across the Solenoid..

 

Here is what you need to start -

- at least 10.5-10.7V when the glow plugs are on.
- at least 100 rpm's
- ICP of 500 psi. If you unplug the ICP sensor the PCM will not get the reading from the sensor and default to 750 psi.

I always start by checking th batteries, have them load tested and check the CCA's (cold cranking amps). Autozone, O-Riely's etc will do his for free.

Ohm the glow plugs and check the GPR.

If you can, monitor the rpm's & ICP while trying to cold start the engine. A bad starter and/or batteries will result in a rough smokey start as well.

 

...and the PCM/IDM sync signal - this shows as 0.6ms FIPW. Once the other minimums are met, the FIPW will jump above 3.0 ms. If that FIPW jumps and you don't at least have some smoke - fuel pressure or bad UVCH.

 

Thank You!!
GP testing is definitely in my future. I plan on probing the connectors as soon as I can.

How would a bad starter cause this?

I'm pretty sure the batteries are solid:
I tested the batteries independently from each other and found the following:
12.57 Volts w/no load
11.33 Volts w/100A load

 

a bad starter that is not producing enough rpm's. A few years ago I had extended cranking times and smokey/stumbling starts. A new Stancor GRP, new Motorcraft glow plugs & new UVC Harnesses helped but did not cure my problem. It still would crank 5-7 seconds before starting and stumble. Took the starter off and it sounded like a baby's rattle when I shook it. New starter and all was good again.......

 

P.S. to test the GPR you can swap it out with the AIH relay.

 

My starter is definitely a slow turner. It'll probably be the next hard part I replace. I'm thinking the "newer design" would be better...?
I should've mentioned, I'm currently using the AIH relay for GPs. Swapped last season when the factory GPR failed mid-winter.