Perplexing problem for y'all. My friend has a 99 F-350 that has a Cold temp no start issue. This is ambient temperature, nothing to do with the engine temp. When it's above 62* out it's fine. Will start every time. Below that and no dice, once it threw the code "P1670 EF Feedback Signal Not Detected" but it has not since then, The only thing that has been changed of recent is a Water pump and a Crank Position Sensor.. Could the CPS have been faulty and when it's cold out it just not go, or a solder point in the Injection or PCM computers be fiddly in the cold weather... It ran fine last year at this time never gave an issue. Truck has 317-320,000 Miles on it... Any suggestions?

it's a 7.3L Power Stroke.

 

Here is a cold weather sticky from 1999 - 2003 7.3L Power Stroke Diesel - Ford Truck Enthusiasts Forums

https://www.ford-trucks.com/forums/1...ky-thread.html

So you are saying that even if the oil temp is up, maybe by plugging in for a few hours, that with ambient temperatures below 62 it will not start?

Any smoke while cranking?

 

I should Clarify this some.. My original post was too Ambiguous... Engine stone cold, Temp below 63. The Truck will not start, There's no smoke white or other, Engine just cranks, dosnt try to "kick over" We've never gotten it running to the point of it being warm and trying to restart it. It just will not go.. It's the oddest thing... when it's over 63, It'll start no issue. Glow plugs checked out of the truck all glow hot, I'm thinking it's related in the computer that a solder point has just come loose over time rough roads etc... the things that were changed like I noted before is the CPS (crank sensor) it has not had the Recall work done as this is a service truck loaded with tools and none of their lifts can handle the weight.. I hope this helps some...

 

Are u sure there is no plug? Being a Florida truck, its liable to still be tucked up into the bumper pretty good. It took me a while to find the plug on the sister truck to the one I own. It had been in ga and never been a problem until it got wrecked.

 

If GP's tested fine, are you certain the GP relay is working? Pretty common issue, I've been through 2.

I would almost guarantee the cord is there, it is likely still tucked up in the bumper near driver's side tow hook, below headlight. I don't see why someone would have cut the block heater cord off of a diesel. Even though I rarely use mine unless under 20F overnight.

 

Well, if the Controller is shot would the 'wait to Start' Light still work? I know it still comes on when you turn the key to glow/start. The cord is not there. It's gone

 

Yes the WTS light has nothing to do with the GPR turning on.

 

Well, it's certainly worth checking out at the very least. How would you test it? I'm sure it's completely different then whats on my Mercedes car, where it has a strip fuse in it..

 

Just use a meter on the large inboard post when the GP's should be energized. Here is a video by ken(woodnthings)

<iframe width="560" height="315" src="http://www.youtube.com/embed/zge6uHOPcn8" frameborder="0" allowfullscreen></iframe>

 

I'll pass along the info. Can you think of anything else that might cause an issue?

 

Worn injectors would cause cold start issues usually fine after they are warmed up, weak low pressure oil pump, weak batteries or starter.

That's all I can think of right now.

 

The glow plug relay-(controller) is directly behind and to the left of the fuel filter housing on the passenger side valve cover side. You will see 2 solenoids that look the same. The farthest one back is the one u want. The other one is for the air intake heater and really does not matter, especially in Florida. On the GPR, is two large wires and two small wires. One of the large wires should have power all the time. The other large one should power up with the key on and the WTS light on. If the other large one powers up, it should be within a volt of the other large one. The two small wires- one is a power that comes on with the key and the other is a ground from the PCM to energize the GPR.

If it is bad and money is a factor, you can get the NAPA gpr-109 for less. Whatever you do, DO NOT put a starter relay on it like is on the inside of the passenger fender. It looks really similar but will fry your pcm.

Well, Bigal beat me to it. Good luck.

Also, clean the battery terminals really well even if the look clean where they clamp to the posts. You will be surprised at how much better it cranks.

 

With the hood up, I can hear that relay clicking. I'll still have my friend check the flow of power but to cover the bases, does clicking mean it's good?

 

I'll pass it along. Doubt he'd use a NAPA Part. he usually gets the Genuine ford parts.

 

Not necessarily, they are known to pit the contacts inside causing it not to flow current through them, a quick check or bypass would be to take a screwdriver across the terminals for 30 seconds or so and see if it will start then.