glow plug testing??
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Senior User
Joined: Feb 2008
Posts: 268
Likes: 1
From: Cape Girardeau, Missouri
glow plug testing??
My truck has become hard to start. What I mean by that is that it takes several seconds to start longer than it used to. I have new batteries, so it cranks over fine. All maintenance is up to date and oil is relatively new. My glow plug relay tests fine and appears to be working properly. The PCM is telling it to engage and appears to be sending power to the glow plug connectors at the valve cover harness. I have tested the glow plugs resistance as per the sticky instructions and all over them measure between 1.8 and 2.3 ohms. I realize that this is outside the optimum .8 to 1.5 that the sticky indicates they should be, but they aren't outside of that parameter by much, and they are pretty consistent. Are these readings indicating that weak glow plugs may be my culprit here?
Thread Starter
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Senior User
Joined: Feb 2008
Posts: 268
Likes: 1
From: Cape Girardeau, Missouri
I believe they are probably the originals, and if so, they have 191,000 miles on them. I guess I've got my money's worth out of them. I have read through the sticky very quickly on replacing them, and I got the message really quick not to use Autolite glow plugs. I also saw that sticky post was over 12 years old. Is this still true? Do any of you guys that have done this job have any other advice for a first timer, since I will be doing this job myself. Thanks everybody
Hotshot
Joined: Mar 2014
Posts: 10,750
Likes: 1,065
From: Douglassville, PA
Replacing glow plugs isn't too bad. The lower rear bolts on the valve covers can be a bear and you'll need either a swivel or a swiveling socket. Things are tight in there and you won't be able to back the GP all the way out with the socket on it. Just knock it loose then feed a piece of fuel hose (not sure what size) down onto the GP to unscrew it the rest of the way.
Lead Driver
Joined: Jul 2003
Posts: 7,404
Likes: 52
From: Wheatland, Mo
What they said....Motorcraft only... Avoid swelled GPs and the next time you change them out you wont have one break off in the head.
Walleye gave up my next tip.... rear bolt on the valve covers can be a pain without the right tools. I used the socket (1/4in drive), short extension w/ ratchet and this should just clear the top of the valve cover to take it off. Also, I put a piece of masking tape over the end of the socket so when it went on the bolt it created a bit of pressure so the nut came out with the socket. Easier than trying to reach for it blindly.
Otherwise it is all pretty easy...just a lot to take off.
Walleye gave up my next tip.... rear bolt on the valve covers can be a pain without the right tools. I used the socket (1/4in drive), short extension w/ ratchet and this should just clear the top of the valve cover to take it off. Also, I put a piece of masking tape over the end of the socket so when it went on the bolt it created a bit of pressure so the nut came out with the socket. Easier than trying to reach for it blindly.
Otherwise it is all pretty easy...just a lot to take off.
Thread Starter
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Senior User
Joined: Feb 2008
Posts: 268
Likes: 1
From: Cape Girardeau, Missouri
thanks for the helpful tips everyone! I think I might just do the injector o-rings while I'm already in there replacing the glow plugs. Do you guys think this is a good idea, or should I stick to the "if it isn't broke, don't fix it" logic?
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Hotshot
Joined: Mar 2014
Posts: 10,750
Likes: 1,065
From: Douglassville, PA
I don't fix what ain't broke but I am well acquainted with Murphy, he rides on my shoulder and I am no stranger to breaking something else in the process. You know, a 'no good deed shall go unpunished' sort of thing. You may have better luck and want to do them.
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Post Fiend
Joined: Mar 2015
Posts: 5,277
Likes: 32
From: Blairsville, Pennsylvania
O-rings and glow plugs are about $10/each, per cylinder for Alliant (only use these OEM orings) and Motorcraft GPs.
I would suggest replacing the UVCH harness while there, too. I used the Dormans, which have an integrated gasket and harness. There were some who had trouble with very EARLY versions, but I have yet to hear of any trouble with recent ones, like mine.
Take care of those things and switch to 5w-40w synthetic Rotella T6 oil, and use a quality additive (PS white bottle when cold, gray when warm weather) and you're 90% of the way there.
My truck went from a plug-in monster when it got cool with romping and occasional no-start, to "always starts" in the coldest weather without plugging in and under 2 secs.
The symptoms you describe are par for the course as these trucks age and gain mileage. Fortunately, thanks the shared experience of so many, they are easy to fix and revitalize.
Exciting times lie ahead
Fleet Mechanic
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
i bet that 5w-140 T6 is HARD to find..
doing the same thing this weekend changing from motorcraft 15w-40 to the T6 5W-40 came up a gallon short.. got 12 needed 16. I did pump out the HPOP reservoir and refill as well.
Plus change out filter on bypass filter i installed last year.
I have heard/read another thing to do when you have valve covers off when doing glow plug and/or replacing o'rings on injectors is to get a shim kit for injector solenoid especially if you have 150K or more miles.
I tend to abide by the "no good deed goes unpunished" model as well but sometime you have to say "what the hell, stay calm and carry on".
have a good one
doing the same thing this weekend changing from motorcraft 15w-40 to the T6 5W-40 came up a gallon short.. got 12 needed 16. I did pump out the HPOP reservoir and refill as well. Plus change out filter on bypass filter i installed last year.
I have heard/read another thing to do when you have valve covers off when doing glow plug and/or replacing o'rings on injectors is to get a shim kit for injector solenoid especially if you have 150K or more miles.
I tend to abide by the "no good deed goes unpunished" model as well but sometime you have to say "what the hell, stay calm and carry on".
have a good one
It sounds like a very sound plan!
O-rings and glow plugs are about $10/each, per cylinder for Alliant (only use these OEM orings) and Motorcraft GPs.
I would suggest replacing the UVCH harness while there, too. I used the Dormans, which have an integrated gasket and harness. There were some who had trouble with very EARLY versions, but I have yet to hear of any trouble with recent ones, like mine.
Take care of those things and switch to 5w-140w synthetic Rotella T6 oil, and use a quality additive (PS white bottle when cold, gray when warm weather) and you're 90% of the way there.
My truck went from a plug-in monster when it got cool with romping and occasional no-start, to "always starts" in the coldest weather without plugging in and under 2 secs.
The symptoms you describe are par for the course as these trucks age and gain mileage. Fortunately, thanks the shared experience of so many, they are easy to fix and revitalize.
Exciting times lie ahead
O-rings and glow plugs are about $10/each, per cylinder for Alliant (only use these OEM orings) and Motorcraft GPs.
I would suggest replacing the UVCH harness while there, too. I used the Dormans, which have an integrated gasket and harness. There were some who had trouble with very EARLY versions, but I have yet to hear of any trouble with recent ones, like mine.
Take care of those things and switch to 5w-140w synthetic Rotella T6 oil, and use a quality additive (PS white bottle when cold, gray when warm weather) and you're 90% of the way there.
My truck went from a plug-in monster when it got cool with romping and occasional no-start, to "always starts" in the coldest weather without plugging in and under 2 secs.
The symptoms you describe are par for the course as these trucks age and gain mileage. Fortunately, thanks the shared experience of so many, they are easy to fix and revitalize.
Exciting times lie ahead
Fleet Mechanic
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
not sure where i heard or read it most likely on ford forums. I got the kit off ebay. let me see what i can find to remember.
I think I was looking for hard start in cold and found info ..
try a search using shim kit injectors or something like that..
94-03 7.3 POWERSTROKE injector tuneup SHIM kit w/ DIPACO SCREWS,( NO TOOLS ) | eBay
here is link to ebay listing.
I think I was looking for hard start in cold and found info ..
try a search using shim kit injectors or something like that..
94-03 7.3 POWERSTROKE injector tuneup SHIM kit w/ DIPACO SCREWS,( NO TOOLS ) | eBay
here is link to ebay listing.
Cargo Master
Joined: Oct 2007
Posts: 2,712
Likes: 107
From: BoCoMo
Just wondering why you are replying to a threat from 2017?