I've replaced 2 glow plug relays on my 97 F250HD (141K on it) over the past 36mo. The truck starts like a champ after replacing them but now for the 3rd straight year, I'm having hard start/white smoke issues again. Thinking I need another GPR. Anyone know why my truck likes to eat glow plug relays? Any help is appreciated.

 

try a stancor

 

only 2 gprs? wow you got off lucky. that is a comon failure item. find in this forum the stancor thread it will help you solve your problem

 

Welcome to

Have you tested your glow plugs to be sure they haven't gone bad? I agree the GPR is probably the culprit, but might as well check everything while you're at it.

The Stancor Relay (586-902 seems popular) might help in the long run if your GPs test good. There's a thread talking about getting this relay from Mouser. I also believe the Stancor 586-903 relay was mentioned once or twice during conversations about what to replace the GPR-109/110 with when it came time to do so.

 

I'm putting a switch on mine right now so I can turn it off when its warm. They get used too much anymore so idiots that don't understand that a diesel is supposed to make noise don't bring it in every time they hear a cold startup.

 

I'm with you on the switch, let us know how you do it.
I don't understand the last part of your comment please explain for us PSD dummys.

 

what is the warmest outside temperature that you would want glowplugs opperating? i would put a thermostat in line with the ground from the IDM. too easy to forget a switch. i work in the HVAC field so I have access to all kinds of temperature controls. seems like you really wouldnt need GPs in weather warmer than say 55 degrees? thats easy. you could use a fixed temp or adjustable temperature control. I prefer to just let the pcm do its thing.

 

Pretty sure our trucks read EOT and Baro to decide how long to energize the glow plugs. So really, your truck does it for you. The colder it is outside, the longer the glow plugs will be active. The warmer it is, the shorter amount of time they will be on.

Heres a diagram.

 

To do the switch mode I received this info and I share to you:

MODE 1
To do the glow plug switch, locate the glow plug relay (looks like the starter relay that’s on the fender) on the front right (passengers side) of the engine, under the cover. There will be two big wires and two small wires, disconnect the two small wires or unplug them if yours has the plug. With a volt meter or test light, find the one that has power when the key switch is turned on. Cut this wire, add enough wire to go inside the cab to the dash, attach a switch, run wire back to the other end of the cut wire and attach. Re-connect the two small wires to the relay. Your "Wait to Start" light will still come on, but your glow plugs will not have any power unless you flip the switch.
<O</O
MODE 2<O</O
Turn your key on and check to see if you have power on one of the small wires to the GPR. The other small wire should show a ground, if it does not then the PCM is not completing the circuit. Take this wire, cut it, splice into it (I would run two sizes bigger "lower #") and run it to a switch (that you mount in your dash) then to a small 12 volt LED light (color of your choice) then to a good ground. The switch could be a momentary one if you want to hold it in until you start or a regular one (the regular one will keep your glow plugs on until you turn it off, so don't forget to turn it off).<O</O
Both of them work, but the first way, lets the PCM turn off the glow plugs if you leave them on.<O</O
The second way, you have total control over the glow plugs and as long as the switch is on the glow plugs are activated. If you leave the switch on for two hours the glow plugs are on for two hours.

So, pick the one that is best for you. I did the mode 1 for peace on mind and works very well.

Good luck. <O</O

 

Thank you guys for your advice and comments. When the snow melts a little i will change the relay to the new stancor. My truck has about a foot of snow on it now, and is 2wd so don't drive it in snow anyway. I usually start it every two weeks or so, and if I plug it in for a few hours it usually starts pretty well considering temps have been teens to 20 degrees when I try to start it. Last time a couple of weeks ago It didn't start quite as easy, so I tried again the next day having it plugged in about the same amount of time, but this time I jumped the two large pins on the relay with a jumper cable clamp waited about 35- 45 seconds and it started right up. Thats when I decided to order a new stancor relay.

 

On my 86 I have manual glow plugs.

First start of the day in the summer, 5 seconds glow.
The rest of the day, no glow plugs at all.

Winter, 12 seconds for the first start of the day.
After that as long as the coolant temp is over 100 degrees, no glow plugs.

Granted the 6.9 glow plugs heat a lot more in less time, so the times are a bit short for the Stroke plugs.
But only using glow plugs when they are needed versus every time you start the engine makes both the relay and glow plugs last a lot longer.

I actually had to replace my GPR 109 stock relay on my 86 last year.
It only had 470,000 miles on it.

I already had to replace the GPR 110 on my Stroke, 90,000 miles on it.

I guess I know what I will be doing to my Stroke next summer, it's to cold to work on wiring right now.

During the winter

 

Interesting Information Dave,
is there any info out there about length of time to cycle the glow plugs on our PSD's. Like how long for 1st cold start at temps below 50* ____, below40*____, below 30*____, below 20*____, below 10*____ ?
I know it would make a difference if it was or wasn't plugged in for at least 3 hours for temps under say 30*. I have read that our gp's will cycle for up to 2 minutes before shutting down. I don't think I have ever let them cycle that long though. I usually wait 30 - 60 minutes, if it don't fire up I repeat.
The wait to start light seems to be a joke and not of any use, I always watch the amp draw on the gauge and count to 30 or so for seconds before trying to start.

 

I have not been plugging my Stroke in and was starting it....attempting to start it when the light went out.

That worked OK down to about 30 degrees.

I found that at 5 below, a 20 count had the engine firing up like it was 70 outside, except for the white unburned fuel smoke.
The after glow did cut that down in about 15 seconds after the engine started.
Why the Stroke plugs stay on for 2 minutes is beyond me, I know my IDI plugs would be toast by the time I see the volt meter pop back up when they turn off.

Down to zero I give it a 15 count, and the wait to start light is going off at 10 for a reference as to how fast I count.

After years of counting down the IDI, the Stroke light always goes out between 9 and 10 count.

I think my method of attack would be first find out how much glow time your engine likes before it starts.
The mileage and condition of each engine is slightly different, and the fuel each of us is using is also slightly different.
So what each engine wants as a glow time will also be slightly different.

Then watch the exhaust for how much after glow you need to keep the white unburned fuel smoke down to a reasonable level.

What almost requires getting out to smell the smoke is the water vapor in the exhaust condensing looks just like the white fuel smoke at very cold temps.

The "Wait to Start" light is OK for temps above 35 from what I have noticed.
Below 35, you better wait for a few more seconds if you want it to fire and run on the first revolution.