Hard Start Glow Plug Relay??
- Thread starter jetflyr
- Start date
DaveBen
SDD Senior Member
If your batteries are good, you can jumper across the glow plug relay with a jumper cable (the big posts on the relay) and that will confirm or eliminate the relay as the problem.
Dave
Dave
CHPMustang
Senior Member
Whats the age of your batteries as they'd be the first suspects I'd check out.
Scarlet_Nape
PITA
Might, also, be your glow plugs:
"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. "
"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. "
I'll also add that I think the Stancor relay upgrade is a nice replacement for the stock. It's a lot more heavy-duty than the stock one, and I don't think it is prone to failure like the stocker is. Much cheaper too..I think I paid 20 or 30 bucks for mine..
Not sure about the battery age. The truck was used. I figure I will start with batt voltage. I think from another thread I saw 10v or better? Then progress on to the relay test and glow plugs. If I decide to replace the relay. Is this difficult. Is it pretty straight forward as far as looking at what unbolts and unplugs? Thanks.