The Diesel Stop banner

1 - 12 of 12 Posts

·
Registered
Joined
·
241 Posts
Discussion Starter #1
Have had this problem with the truck since I bought it. If it gets left outside overnight even at 0'C it will not start unless it's plugged in. I originally thought it was GP's so I changed all 8, still the same thing. I only get about a 0.3 voltage drop across the GP relay and from what I've read that is acceptable. The truck almost always overnights in my shop but even then I still plug it in because it runs very rough after start up until it has warmed up. This last week the truck got left outside all week at a Park and Jet at the airport not plugged in. When we got back the weather had turned bad and it was about -15'C out. Tried to start the truck, no go. Left it for the night and went back this afternoon, temp had come up to about -2'C, still no start even with a shot of ether and an F250 with both batts jumped and the F250 in high idle, also using a MM to make sure cranking voltage never dropped below the magic 10.5. Towed the truck over to a plug in stall and left it plugged in for a few hours. Came back and truck started right up with no problem. I am stumped on this one guys, GP system is working properly to my understanding and batts are good, what else could it be? Also my fuel bowl heater is disconnected due to the usual. Is it possibly a fuel problem? Thanks.

Mattski
 

·
Registered
Joined
·
813 Posts
i would unplug the connectors at the valve covers and check to see if you get voltage on the glow plug pins when the glow plugs are cycling. you could use a simple test light to check for voltage.
 

·
Registered
Joined
·
2,980 Posts
"Usually" cold start problems can be traced to bad GP's, GPR, weak batteries or starter motor. I see you have checked the GP's and relay. So next I would have the batteries load tested. You need two good batteries to start these PSD in cold weather. If the batteries are okay then have the starter motor tested. It would probably be best to remove it and have it tested. If the starter is okay then give all the battery cables the greasy eyeball test. Make sure they are good and tight without any signs of corrosion. If all the above is good, check the condition of the diesel fuel inside the fuel filter canister. If it is dark in color you might have some bad injector O-rings. What type of engine oil are you using?
Griz
 

·
Registered
Joined
·
241 Posts
Discussion Starter #4
Starter motor and batts were new when I bought the truck (Dec). Fuel filter has been changed twice and fuel in canister looked good and clean both times. I am running 15W40 Pennzoil Diesel oil in the motor. The more I think about this problem it seems to me like the GP's aren't working even though all the components test OK. I think next step is to check for voltage at the VC conn pins while the GP's are cycling like juyler suggested. GP pins are the outer ones correct? Any other things that need to be checked in the GP circuit while I'm at it? Also, WTS light "on" time does change depending on outside temp, indicating to me that those sensors are operating correctly.
Thanks

Mattski
 

·
Registered
Joined
·
2,980 Posts
Yes...the outer two pins are to the glow plugs on each connector.

Griz
 

·
Registered
Joined
·
2,980 Posts
I know you said you had new glow plugs...but have you measured their resistance? I would and make sure they read less than 2 ohms. Ford says .1 to 6 ohms the GP's are good. The part the bothers me is you said it starts fine if plugged in. Usually this is an indication one of the four major components of the glow plug system is bad. Just because some thing is new doesn't mean it is good. Good Luck!

Griz
 

·
Registered
Joined
·
226 Posts
I had a similar problem a couple of times. The GPR showed good voltage in and out but the connection at the post, both nut & threads and wire eyelet, were oxidized and the power wasn't getting through to the GP's. I caught on when the post got really hot one time. It looked clean and normal. With 0W40 synthetic my truck will start, unplugged, at -35C. In fact I never plug it in.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #9
Checked my GPR the other night and no voltage coming "out" with the key on. Ordered up a new relay and installed today. Still no voltage on the "out" post with the key on. I have good voltage at the "in" post and voltage at both small terminals (with key on). I also get continuity to ground at all times on the out post. Seems to me this would be a short in a GP? I did check resistance on all the plugs when I installed them and they were all about 0.6- 0.9 ohms. What are the other two major components of the GP system? Thanks

Mattski
 

·
Registered
Joined
·
2,980 Posts
Checked my GPR the other night and no voltage coming "out" with the key on. Ordered up a new relay and installed today. Still no voltage on the "out" post with the key on. I have good voltage at the "in" post and voltage at both small terminals (with key on). I also get continuity to ground at all times on the out post. Seems to me this would be a short in a GP? I did check resistance on all the plugs when I installed them and they were all about 0.6- 0.9 ohms. What are the other two major components of the GP system? Thanks

Mattski
To check the GPR for a short on the output side...remove the wire that is connected to the big output post and retest. You should have battery voltage on both large posts for a period of time after the key is on. Because the glow plugs are hooked in parallel you see very little resistance to ground when they are hooked up. Are you sure the relay is being activated by the PCM?

Griz
 

·
Registered
Joined
·
241 Posts
Discussion Starter #11
Ok, disconnected the out side of the relay and I get good voltage. Then I reconnected the GP wire and cycled the key again. I get voltage there now and I can hear the relay making! Cycled the key several times and same result. I'll leave the truck unplugged tonight and see how she starts in the am.
Thanks
Mattski
 

·
Registered
Joined
·
2,980 Posts
Ok, disconnected the out side of the relay and I get good voltage. Then I reconnected the GP wire and cycled the key again. I get voltage there now and I can hear the relay making! Cycled the key several times and same result. I'll leave the truck unplugged tonight and see how she starts in the am.
Thanks
Mattski
Sounds good...let us know how you do.

Griz
 
1 - 12 of 12 Posts
Top