Hard to Start

[tim connell]

I have a 96 F-350, and it is starting to get cold here in PA. I would wait for the "WAIT TO START" indicator to go out and try to start my truck. It would have a real hard time starting, and when it did billow of white smoke came out. So I decided to check the on time of the glow plug relay. It would stay energized for 75 seconds yet the indicator light went out in about 40 seconds. After the 75 second wait, the truck started, still with white smoke but seemed alot esier. Any input would be a big help. thanks.

[vitalidle]

The white smoke at startup is unburnt fuel. Start by checking the glow plug relay first. Its on the top front passenger side of the motor. Its a 4 post relay. There is two large posts one will be hot from the battery. Check the opposite large post with the key cycled to the wait to start position and you should have 12 volts to the other large post.

[tim connell]

I have checked the relay, and it does function. The problem is that i have to wait at least one more minute after the wait to start light goes out and then the truck starts a little better. in other words what ever tells the wait to start light to de energize is telling it too soon. thanks.

[vitalidle]

Actually the glow plugs continue to heat well after the light goes out. In fact I believe they will continue to heat for up to 90 seconds after the light goes out. My guess is your glow plugs could be going bad if they are the orginals.

[NCHornet]

If the GPR is good you need to check the GP'S. Just pull the UVC connection on both sides coming from the VC and OHM test the GP's. These will be the two outside prongs on each end, the 4 in the middle are for the injectors. They should all be close in OHM's, if you get an infinite reading that GP is bad. It can also be your batteries, if they are more than a few years they could be bad.

[NCHornet]

Maybe the sponsors can post this as a sticky as I have been replying to a lot of these hard start threads, which always happens when it starts to get cold.
Here goes and I hope it helps.

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.
· Locate the GPR – Its behind the fuel filter on top of the engine, a little bit toward the passenger side of the valley. There may be two relays there. If so, the rear one is the GPR. It will have two fairly large wires (yellow and brown) connected to one of the large posts.
· With your multitmeter set to DC volts, and 15 V range (if not autoranging), clip the positive (red) lead to the output terminal (with yellow and brown wires connected), and the negative (black) lead to a good ground point (like the battery ground terminal or someplace metal directly on the engine block.)
· Turn the key to ON (do not start)
· If your GPR is good, it should click, and you’ll see 11 volts or so on your meter, then, depending on temperature, it will click off up to 2 minutes later. You should do this a couple of times to make sure it consistently makes the connection.
· If you don’t get voltage with this test, confirm by retesting as follows.
· Remove the two small wires from the smaller two of the four GPR terminals.
· With jumper wires, apply voltage from the battery across the two small terminals. If your voltmeter now reads voltage on the output terminal, your GPR is OK, and your problem is in the PCM circuit that tells the GPR to activate.

To check Glow Plugs.
· Remove the electrical connector on the inboard side of valve cover at the gasket. Press down on the top of the connector latch and pry gently with a screwdriver. Photo of disconnecting one and another Photo of it loose.
· There will be 9 pins on the valve cover gasket where you removed the connector. The two pins furthest forward and the two pins furthest back are for your glow plugs.
· With your multimeter set to resistance (ohms) and low range (single digits) if not autoranging, clip the negative (black) lead to a good ground point.
· Probe each of the 4 outer pins individually with the positive (red) lead, noting the resistance. Good glow plugs will have a resistance between 0.6 and 2 ohms. If you get infinite resistance on any glow plug, that one is either bad or the connector under the valve cover has come loose.

[vitalidle]

Thanks for the info will post it up as a sticky.

[vitalidle]

Here is the link to the stickyTroubleshooting GPR & GP's

[NCHornet]

Thanks for doing that. As the weather gets colder we will see a lot of Hard Start threads popping up. Hopefully this will help some of those folks.
I just can't say how much better the Stancor GPR is over anything else you can buy!!

[NCHornet]

Maybe you can add this to that sticky,
If your GPR is bad you can use the factory replacement for around $75, Napa's GP110 is close to this price maybe $10 cheaper. But you can get a GPR 109 from Napa for around $22.00 This is the same exact relay as the GP110 except the mounting holes are rotated 180 degrees, which is no big deal as the wires stretch just fine.
Now if you are tired of replacing your GPR and want a H.D. alternative may I suggest the Stancor 586-902. This is a large relay and it can truly handle the large AMP draw our trucks call for at start up. Gopher Electronics has these for under $40. I know several folks that live way up North (Alaska, Canada) where they know about serious cold starts and they all swear by the Stancor. I am very happy with mine, I believe I have pics of mine installed in my webshots.
Just thought I would add this info.
Take Care
Kevin