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Hard/No Start? Check here first.

375K views 82 replies 42 participants last post by  meador123 
#1 · (Edited)
Thought I'd post this as a sticky thread now that cold weather is on us.

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. (if oil temp is above 130F, it won't turn on at all)
· Locate the GPR – It's 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 the large post without the rubber boot.
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Another location photo here:
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Photo credit F350_6

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.​

GPR for 99 & up 7.3L
Ford F81Z-12B533-AC
NAPA GPR#109 (mounts 90 deg out of rotation from original)
Carquest #RY-175 (clone of GPR#109)
Autozone Sorensen MR-99 (also clone of GPR #109 I think)
International #1831646C1 (Identical to the one you'll get from Ford) ~$25-$30
[added on edit] A forever GPR - White Rogers/Stancor 586 902


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.​
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Disconnecting VC harness connector.
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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.​
 
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#27 ·
I just replaced my 6+ yr olds with the batteries that Costco carries. Made by Johnson Controls (who may make the Motorcrafts) and they have a rating of 1000 CCA, better than the stockers.

You may have something that's draining your batteries when the truck is turned off, since your batteries have been lasting such a short time. That's definitely worth looking into.
 
#28 ·
[ QUOTE ]
Just edited the original post to inlcude pics of getting the VC connectors loose. Also added a note on checking the GPR a couple of times to make sure the good connection isn't a fluke.

[/ QUOTE ]

Thanks for updating with pics. Will try it this weekend.
 
#29 ·
Hey Guys,

I replaced my GPR and Tested all my plugs.. The Plugs 5 and 6 I think.. The ones towards the front of the grill, but the 2nd row.. so not the closest but the ones behind it.. They both show infinite readouts on ohms.. The Others all show .7 Ohms. I dont think 2 bad glow plugs would make it not start.. do you?

However, the truck still has a very hard time starting. its 70 degrees out right now.. and I got it to start once, only to stall.. My batteries are almost dead now with me trying to start it so many times.. And I know that its not the batteries because I can get the truck to start, but it just stalls right after..

My Oil is fine, I just changed it.. and My dad has a 99 7.3L with the same oil and his works fine..
Help!
 
#30 ·
first charge your batteries back up so you aren't spinning your wheels.

i'd be checking hpop oil level, because it is pretty easy.

then I would be trying to figure out if your fuel pump is coming on. When trying to start it, does lots of white smoke come out the tail pipe? by lots, I mean garbage cans full. less white smoke indicates lack of fuel. lots of white smoke indicates lots of unburned fuel, ie glow plug problems.
 
#36 ·
Wow, I just joind this "Site" and after reading the posts on here (from very well informed owners-Thank You) I hope to have my problem (Cold Start, Eradic Idle) issue fixed tomorrow. Thank You All... Happy Holidays
 
#37 ·
I bought my 2000 used, 46,000 miles on her, what battery's do you all suggest to use ? when replacing them. Mine still have the "Stock" Diehards.. ?
 
#38 ·
>>Will it still start in warm weather with a faulty GPR? Do they completely fail or get tempermental???

Depends on if it fails open or closed. If it fails open, yes it will. If, as in the case of mine, the control relay fries or shorts, you will blow the ignition fuse. A 30 amp on my 99 350, right column, bottom. Removing the hot control wire will allow you to keep the fuse in and start. Besure to tape the end of the control wire so it will not go to ground while you obtain a replacement.
 
#39 ·
Awesome thread and I have printed it out as I just started having issues. My issue is that first thing in the morning (mid-30's) the engine cranks and cranks and cranks. After a few tries (key on then off), it will finally start along with alot of smoke out the exhaust (enough I can get out and walk thru the cloud and "enjoy" the diesel smell first thing in the morning. Is this thread related to something I should check first, or do I have bigger problems? I will say, that for the rest of the day, the motor starts with no problem even after prolonged periods of rest.
 
#40 ·
Do you plug it in? Are your GPs and Relay working well. Do you run Synth oil? Yes, there a lot of things here that should help you. If your truck starts fine the rest of the day, it's just sluggish. You should be able to track down the culprit using the stuff on this thread.

Good Luck.
 
#41 ·
Scraper:

My '02 was behaving just like you describe (I live at 8000', and have had some sub-zero mornings in the last few weeks). like you, it would start fine throughout the rest of the day.

I considered replacing the batteries, then found this thread. I changed out the GPR with the NAPA GPR109 ($25, and about 15 minutes), and when I had my oil changed (at the dealer) I requested a winter weight oil - they put in 10w-30.

Starting problems GONE - starts like it should. I think the GPR was the ticket, but with the lighter weight oil (which I'm sure helped), it sure runs quieter.

Phil
 
#42 ·
I have 12.3 at the large post with the rubber boot on it. At the large post with the yellow & brown wires I have .5v. I guess I have to replace it. That post always had voltage to it every time I tested it until today! The rubber boot broke off in little pieces, do I have to replace it? Thanks
 
#43 ·
Ok, I replaced the (2) Batteries (Motorcraft 850's) and the GPR-111 Relay. Last night it got down to 38 degrees. I started her up, she stalled about 2 min out, then was a little bugger to get started again. This time she ran and warmed up properly. Now I did not plug the block heater in. I have no idea what weight Oil is in her at the current time , but I might be going to 10w30.... Any ideas guys. Ceece
 
#44 ·
so if it won't start at all, then eventually TONS of white smoke comes out, then probably, almost for sure, it is the GPR. There is a possibility that most of your glowplugs all went bad at the same time, but if you believe in Karma, then go buy a lottery ticket to even out the odds.

If it starts right up, but blows white smoke for 1 to 5 minutes, and runs really rough at first, odds are pretty good that one or more glow plugs have gone bad, or it could be REALLY FRIGGING cold, like below zero, adn you didn't plug in.

If it starts right up, runs really good for the first minute or 3 with a touch of blue smoke, then all is good with glow plugs.

If after 2 or 3 minutes it kind of fades off and dies, almost always without white smoke other then steam, I'd be looking at fuel pump, fuel pump relay, plugged filter, or jelled fuel. Of the three, jelled fuel is the most common at temps freezing or below.

Powerserve in the white bottle. Your friend.

I'm sure there are other products that work as well, I've just never tried anything else.
 
#45 ·
Just finished the NAPA GPR-109 install a few minutes ago.

A couple of observations:

The GPR-109 is actualy reclocked to 90 degrees counter clockwise. So the wiring clocks 90 degrees counter clockwise.

Although several have said it really does not matter on the big posts which big wire goes to which... That I cannot say. But if you look at the molded in pattern of ridges of the two and clock those the same way... it ends up 90 degree's *counter* clockwise. And thats how I wired it up.

Unfortunately its fairly warm here today and did not get all that cold last night and I forgot to unplug the block heater from the timer last night so I cannot get a really good diagnostic check on it to see if it fixed the problem. I will have to wait for a good cold night and thats a few days away. But.... there was instant start and there was no white smoke at all. And even with block heater in on a really cold morning I was getting a tad for a half a minute. So I think its indeed fixed. But will have to wait and see... but at least thas eliminated from the equation.

And... sadly enough... my "Powerstroke" plastic engine decorator cover, one of the studs broke. I took it off because I was going to change my Fuel filter in addition to this while I was up under there. And one of the two studs gave it up. So at at some point I will have to drill that stud out and mount a new bolt there for my play pretty. /ubbthreads/images/graemlins/tongue.gif
 
#46 ·
[ QUOTE ]

And... sadly enough... my "Powerstroke" plastic engine decorator cover, one of the studs broke. I took it off because I was going to change my Fuel filter in addition to this while I was up under there. And one of the two studs gave it up. So at at some point I will have to drill that stud out and mount a new bolt there for my play pretty. /ubbthreads/images/graemlins/tongue.gif

[/ QUOTE ]

Same thing happened to me the first time I went to remove the plastic cover to get to the fuel filter. Now I just go without the plastic cover.

Hammer
 
#47 ·
[ QUOTE ]
[ QUOTE ]

And... sadly enough... my "Powerstroke" plastic engine decorator cover, one of the studs broke. I took it off because I was going to change my Fuel filter in addition to this while I was up under there. And one of the two studs gave it up. So at at some point I will have to drill that stud out and mount a new bolt there for my play pretty. /ubbthreads/images/graemlins/tongue.gif

[/ QUOTE ]

Same thing happened to me the first time I went to remove the plastic cover to get to the fuel filter. Now I just go without the plastic cover.

Hammer

[/ QUOTE ]

Its highly likely mine will also now become a wall ornament in the shop! /ubbthreads/images/graemlins/wink.gif
 
#48 ·
Finaly got a cold morning yesterday. Started right up with the NAPA GPR 109 and no plugged in.

I have always used my X monitors Tranny temp reading as a reference point to how cold the engine and metal and all is. And I had been starting without issues for years under 35 or 36 degrees. Down easily into the teens and even then second crank with a romp maybe at worst. When the starting problem developed I started having a lot of problems getting her to fire up without multilple cranks (as many as 10 or more) and even then when it finaly cranked white smoke at anything below 40 or so reading to the tranny... So I knew its was out of the ordinary and something was up.

But after install of the 109 and a I had a reading of 26 in the tranny, yesterday, it fired up first time w no smoke. So we back to normal. Definately.
 
#49 ·
Well, so far, I have replaced the MAP sensor, (weird readings at idle) and the GPR. Funny thing, no codes being set! Makes diagnosis difficult. Starting has gotten really lousy the last few days and it hasn't been that cold (20s & 30s at night). Long crank, hits on only a couple, lopes like mad, makes smoke like a earth mover! Will see what happens tomorrow. The GPR tests okay when warm, I'm thinking burnt contacts on the relay causing not enough current to the plugs. NAPA sold me a 110, wonder what's the dif between the 109 and the 110. /ubbthreads/images/graemlins/shrug.gif
 
#50 ·
[ QUOTE ]
.... NAPA sold me a 110, wonder what's the dif between the 109 and the 110. /ubbthreads/images/graemlins/shrug.gif

[/ QUOTE ]

easy enough question to answer....the difference is the counter clock wise 90 degree change in its mounting bracket and about 45 bucks....

I didn't even bother to test mine. Symptoms lead me to believe it was gone... and so I just changed it to the 109 (cheap enough and my old one was 5 years old) to see if that solved it before going futher. And it did solve it so I good to go.
 
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