The GPR looks like the starter rely on the passenger side fender. It is located on top of the engine under the plastic cover that says Turbo Diesel if you still have it on. It will have 2 large wires and 2 small wires running to it.
Great thread. My '96 7.3 was getting pretty cranky about starting in -40 weather. Had it plugged in and all that. Finally changed to Petro Canada's Duron 5-40 synthetic oil and an oilpan heater. I always wait for the GP's to cycle full time before cranking, and it starts right off every time. Smoke? Oh yeah, she smokes, but once warmed up it goes away. Great for keeping the mosquitoes away in the summer .
ok folks I know this is an old thread but figured id give it a try before starting a new one. Heres the history I have a 97 F250 7.3 Turbo Diesel. Cold mornings sucked for me to crank a cpl days ago after a hard start I was ready to park the truck. Before I did it started to run very rough and had low rpms. I shut it down and went to work and tried later that day to start it, NO LUCK NO WAY. I had thought for some time that it was a glow plug issue and I also noticed the starter had some drag to it. I changed the starter and that cured the drag. After reading some on this forum and one from another for 7.3 diesels I tried to replace the Glow Plug Relay. I used the NAPA GPR-109 Part though it was a little different than mine it worked. The old girl tried to crank at this point but still nada. Sooo With the help of a little starter ether I did achieve a start up. However it ran very rough and with it floored i could just get a little over 2000rpm's I also found a fuel leak from maybe two locations. Now understand I am far from being a mechanic and Im not sure of the proper names for the parts but i can describe the areas and some of you guys in the know may be able to help me. Looking at the fuel filter on top of the engine to the right there is a protrusion coming straight out from the side of the engine that would be on the driver side. There is a wire connected to it, is this some sort of sensor? Also to the rear of the fuel filter under the turbo lines there appears to be some sort of device that I suspect may be a fuel pump? maybe lol. there is a huge puddle of fuel gathered under that area. Now I also am curious as to the injector pump Is that the rectangular aluminum looking box that sits in front of the Fuel Filter area. And i really dont have a clue as to where the injectors are im guessing close to the cylinder heads. It has become a matter of pride now that i fix the old girl myself. Im not stupid lol though I am ignorant in this area. any help would be so greatly appreciated thanks in advance folks.
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ok folks I know this is an old thread but figured id give it a try before starting a new one. Heres the history I have a 97 F250 7.3 Turbo Diesel. Cold mornings sucked for me to crank a cpl days ago after a hard start I was ready to park the truck. Before I did it started to run very rough and had low rpms. I shut it down and went to work and tried later that day to start it, NO LUCK NO WAY. I had thought for some time that it was a glow plug issue and I also noticed the starter had some drag to it. I changed the starter and that cured the drag. After reading some on this forum and one from another for 7.3 diesels I tried to replace the Glow Plug Relay. I used the NAPA GPR-109 Part though it was a little different than mine it worked. The old girl tried to crank at this point but still nada. Sooo With the help of a little starter ether I did achieve a start up. However it ran very rough and with it floored i could just get a little over 2000rpm's I also found a fuel leak from maybe two locations. Now understand I am far from being a mechanic and Im not sure of the proper names for the parts but i can describe the areas and some of you guys in the know may be able to help me. Looking at the fuel filter on top of the engine to the right there is a protrusion coming straight out from the side of the engine that would be on the driver side. There is a wire connected to it, is this some sort of sensor? Also to the rear of the fuel filter under the turbo lines there appears to be some sort of device that I suspect may be a fuel pump? maybe lol. there is a huge puddle of fuel gathered under that area. Now I also am curious as to the injector pump Is that the rectangular aluminum looking box that sits in front of the Fuel Filter area. And i really dont have a clue as to where the injectors are im guessing close to the cylinder heads. It has become a matter of pride now that i fix the old girl myself. Im not stupid lol though I am ignorant in this area. any help would be so greatly appreciated thanks in advance folks.
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Your glow plugs are located under the valve covers. If your going to change them, do yourself a favor, and change your under valve cover wiring harnesses as well. Chances are they're original. The bigger Stancore relay puts out quite a few more amps.The harnesses are subject to a lot of heat. Many times, I have heard of old harnesses grounding out, after installing a Stancor relay. I don't want to scare you away frm the Stancore,I use it, and like it a lot. Just be aware that if you do one upgrade, there is usually one, and maybe two additional upgrades you'll have to do to safely support what you just did. Anytime I pull the valve covers, I change out the harnesses. It's cheap insurance. If everything is working fine, you shouldn't have to pull the valve covers more than every 100,000 miles, or so, anyway. If you want to know how to make your glowplugs light, only when you want them to, let me know. It's old school, and I've been doing it for 3 years now with no problems. I'm sure it doubles, or triples glowplug life.
how does the relay flow more current? its a direct link to the battery. it will flow whatever the battery can produce. changing the relay should have no change in current flow to the motor. all it does is withstand the current better then a stock relay.
If you're asking if the Stancore relay flows more voltage, I would think it does not. It is about 3 times the size of a stock GPR though. Check out this link.
Many guys have found our GPR's to wear out quickly, perhaps in less than a year. Some decent aftermarket alternatives are available from NAPA and Autozone, but they wear out, too. Recently there was a discussion about how we really ought to have a heavier-duty relay, the factory spec one is not rated high enough. See this thread for background.
redbrand measured the current through the GPR at about 112A max and suggested a Stancor 586 type relay as a suitable replacement -- rated at 600A inrush and 200A continuous.
I found a Stancor 586-902 relay at Gopher Electronics for about $36 including shipping and decided to try it out. I ordered one, and it arrived today.
It is about 2-3x bigger than the Motorcraft relay, but the mounting bracket looks like it will work without mods. Click here for photos.
I will install it in the next few days and report back on how it goes, also post some more pics of it installed.
Of course, the real test is how long it lasts -- and unless it proves to be a total wimp, I don't expect to be able to report back on that for a very long time.
Shoebear, that's a huge relay! Do they give any specs for trigger amperage requirements? I wouldn't want to overload the glow plug trigger wire/PCM. I'm not sure what the trigger is rated at now. Or maybe you are installing a huge manual switch too!!
Just thinking out loud???
Cheers...
Here is a PDF with the specs. Coil resistance is listed at 21 ohms which would give a bit less than 1A of current. Redbrand measured about 2A on coil of the factory relay. So I doubt if coil current will be a problem.
I don't know the resistance on the factory coil, but I did my math backwards on my reply to Big Bopper. Instead of just over 2A (21/12 - wrong!) as I originally posted, it's just under 1A (12/21). I have edited my reply to be correct now. Since redbrand measured 2A on the factory relay. I think the Stancor will work OK.
I was just browsing some pics on the freeauto site & came across this pic from a 99 & up relays - I wonder if the air heater relay would be a good replacement for ours also?
In the pic it looks physically bigger so i wondered if it may last longer.
I wouldnt have a clue on price of the air heater relay or how well they work in their current application.
Thats just what I am going to do. I haven't done it yet because my GPR is still doing it's job in life, but I sure it's time is coming very soon. I just found that one of my GP's is out. SO it looks like
the GP system will be in need of some work. I am sure I will put the Stancor in then . I am more than confindent about the coil amp rating and the contact ratings of the Stancor. The only thing is how well will it hold up to the heat of the engine. I still think it should be good to go.
Going off of memory but I think the GPR (Napa/Autozone) replacements draw more current to pull the relay in than the Stancor. Hard to beat less than 1 amp of coil current on the Stancor contactor. There was a discussion some time back here about that how much the coil current draw is of the replacment GPRs.
Show us some good pics when you are done!
Good Luck.
Thanks, Redbrand! It was your idea. You did say (in the previous thread) that anyone was free to run with it.
Renegade, the heater relay **looks** the same as the GPR. I wonder if they are the same part number? Do the 99+ PSD's have problems with short GPR life also? I don't know if physical size really makes the difference, but the Stancor is rated at 600A inrush and 200A continuous -- that's what I was interested in, not the physical size (as long as it will still fit easily). I don't know if the Stancor would be a drop-fit for a 99+, the heater relay might get in the way.
OK, I couldn't resist -- I installed the Stancor this morning before work.
Physical mounting was no problem. The Stancor mounting bracket fits the existing studs just fine. I oriented it with the contacts toward the center of the engine, next to the fuel filter bowl. The big wires had to be bent a little, but they were long enough, and there were no problems with routing.
Before I removed my existing NAPA relay, I measured the coil current at about 3.5A. Then I measured the Stancor after I installed it -- 0.5A. Therefore, I think there will be no problem with excessive coil current draw.
The Stancor spec sheet says, "Note: Caution must be used in coil selection for use in 12 volt systems where battery charging may expose coil to continuous, higher-than-rated voltage." Based on that, you could make a case for using the 15V version of the relay. I chose the 12V version because
The GPR is not operated continuously
The current draw of the GP's is enough to depress system voltage, even after the engine starts and the alternator is running (ever notice how your headlights get brighter after the GPR shuts off?). Because of this, the 15V relay may actually not work properly before the engine starts and tha alternator kicks in.
Redbrand wondered if the underhood temp may be too high for this relay -- Stancor specifies 149ºF max. However, I think we can fudge that because
The GPR only activates when the engine is cold
The GPR is not operated continuously, and the spec sheet is for continuous operation.
In the next day or two, I will measure the coil current of my old Motorcraft relay (contacts are bad, but coil still works) just to make absolutely sure about the coil current draw. I will also take pictures of the install and post them.
I am not an electrical guru by any means (my disclaimer) but I did tear one apart & it looks like if they would only make the contact disc out of something a lil better quality that 99% of our ailments would be nonexistant.
I checked the coil current draw of my old Motorcraft GPR tonight -- 4A. This means the NAPA draws a bit LESS (3.5A) than the Motorcraft, and the Stancor is way less (0.5A). So we can put to rest the idea that the Stancor draws too much coil current.
Since I installed the Stancor relay, I have noticed hard starts and a puff of white smoke when it does start. Tonight, with my wife's help at the ignition switch, I checked the relay voltages carefully to be sure it is working right.
All the voltages look good. The relay definitely turns on the GP's, and the GP's pull current. The large post connected to the GP's goes from 0V (relay off) to about 10.5V (relay on), then after 5-10 secs, climbs up to about 11V. This is about what I would expect.
I also tested the voltage drop across the large posts while the relay operates. When it first turns on, I see about 75mV (0.075V), then it drops to about 50mV after 5-10 secs. This seems reasonable, and in line with what I've seen in other posts about what this should be.
So the Stancor GPR is working OK, but I may have a bad GP or two. I didn't have time to check that tonight, I had to help put the kids to bed.
[Added on edit: While I was at it, I monitored the system voltage while my wife started the engine. Even with the engine running, it never got above about 12V. So I think the 12V version of this relay is the correct choice, not the 15V version.]
Sorry I haven't been able to post pics of the install yet, it's dark when I get home from work and my digital camera does not have a flash. I will take pics this weekend during daylight.
The bigger Stancore relay puts out quite a few more amps.The harnesses are subject to a lot of heat. Many times, I have heard of old harnesses grounding out, after installing a Stancor relay.
you stated that the stancor relay flows more current then the stock unit. that is not possible. it is a relay.... an overgrown on off switch. it uses a small current to control a large current. all you do by installing a stancor relay is put a heavier unit in place. its the exact same thing as going to home depot and buying the .89 cent light switch or buying the 3.99 light switch. they do the exact same thing but one is heavier then the other and will last longer.
your statement is incorrect.
also, flow is not voltage as your last post states as well, flow is amps, voltage is what pushes the amps through the circuit. the stancor relay will not allow for anymore voltage or amperage to reach the glow plugs then a motorcraft relay. again, all it does is give you a longer lasting unit.
the rating of 112amp on the motorcraft and 600 amp on the stancor does not mean that it will produce those amps, it means that it will not melt or fail until those amps are met. the glow plug system will only use what is needed to move the current from the batteries to the cylinder head and back to the batteries. the glowplug system will never reach those kinds of amps. only way possible is if a glowplug was broken and became a dead short, or a feed wire became a dead short. Either way you look at it the 14 gauge wire would vaporize long before the relay reached a high amperage reading. The current will only flow to the extent of your weakest link in the system.
i thikn the relay control wire is 16 gauge, i was refering to the wires that go to each glow plug, but i really dont recall the exact size of them, all the matters is that they will not handle anywhere near the amperage that the relay is rated to handle
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Re: Stancor heavy-duty GPR replacement ?? 
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. I am more than confindent about the coil amp rating and the contact ratings of the Stancor. The only thing is how well will it hold up to the heat of the engine. I still think it should be good to go.
