I'm working on a 2000 F-350 with a 7.3 (49 state, Standard shift if it matters) that has 250,000 miles on it. It runs fine once we get it started, but getting it started is pretty difficult these days, at least when it's cold. It cranks fine and will even clack like it's trying to start, but it can't quite get the job done. If I plug it in for a few hours, it'll fire right up.

The truck's been all over the place to try and get this thing fixed. Judging from the looks, it has had a new Cam Sensor in it recently. Here's what I've personally done to it so far to try and nail this thing down:
- All new Glow Plugs
- New Glow Plug Relay
- Cleaned terminals at the relay
- Degreased the valve covers and cleaned out the connectors for the injectors and glow plugs with Brakleen & Compressed air
- Scanned for codes...all good on a KOEO and KOER test, nothing in memory
- Checked for voltage drop at the relay...it's only 20 mV.
- Verified PCM signal to the glow plug relay
- Verified that there is fuel flow to the filter housing on top of the engine
- Made sure that the batteries are in good working order and fully charged

The internals looked pretty clean when I had the valve covers off to do the glow plugs, with no looks of leaky high pressure rails or anything like that.

I'd really appreciate it if some of you out there could help a 6.0 guy out. It's been a while since I've spent this kind of quality time with a broke 7.3.

 

What kind of condition is your oil in? Also, before your next attempt to start cold, pull the plug on the top of the HPOP and see where the level is, if it's more that 1" down, that could be your problem.

 

Like Barry said, check your level of the oil in the HPOP. If you have not changed the oil in a while, I would start there. Oil makes the injectors fire, I'm sure you know this.

Good luck.

 

Youve got PCM signal to the GPR, but have you verified with a test light that the GPR has an output signla to the GPs? IOW when the WTS light is on is there power coming off the GPR to the GP's.

Does the truck blow white smoke when trying to cold start?

Hows the fuel filter?

 

Curiuos my self , mine blows white smoke and is hard starting.
so I will be watching this one.


HPOP oil? what kind oil, and how do you drain it? or so you suck it. lol

 

your glow plug relay may have gone south. easy to change, easy to check. Ill give you a pictorial tomorrow.

HPO oil comes from the crankcase, dont drain it, it is a self circulating system. the only way that the resevoir could be low is if the IPR edge filter is letting it drain down, or you have a leak.

 

a couple of questions:
1. what is cold to you? we talking 15 degrees F or 50 degrees F?
2. Do you know how old the batteries are? what is the cranking voltage with the glow plugs on?
3. what is the voltage glow plugs off engine running?
4. what is the voltage Glow plugs on engine running?
5. have you read the amp draw of the glow plugs at the relay? the range is 17-26 amps each, puts you at 146-208 amps draw iff all are working

My F350 kinda did the same thing... I swapped out the relay and it is good so far, but its only been down to about 25 here so far. I have heard stories of weak batteries appearing good but not being able to carry the load of glow plugs plus starter. If it is cranking slowly it may be a starter as well. I don't know how you do a compression test on one of these... but with that many miles compression may be an issue, how much blowby is there once it gets going?

I put in a voltmeter so I can see what the batteries are doing....was a little shocked to see how much the glow plugs pulled it down.

 

You can use a screwdriver and arc across the terminals on the glowplug selenoid if you think the glow plugs aren't getting any juice.

 

Wow! Thanks for all the input. Here's what I got done today with it:

- The Wait to Start light works fine. It comes on for a few seconds, then goes out. I did notice that the glow plug relay stays in longer, but I knew it does that for emissions and what not.

- I pulled the fill plug on the HPOP reservior and found it down about 1 1/4". I topped off the level, which took around 3/4 quart.

- The GPR has power on the red wire and ground on the pink wire as it should. When the relay is kicked in, I've got power on the terminal going to the glow plugs. I put a clip-on ammeter on the cables for the glow plugs. The draw right at initial engagement of the relay is around 150 amps, so that looks good.

- While I was poking around the HPOP reservior, I discovered a diesel fuel leak at the pressure rail fitting at the front of the driver's side cylinder head. I got a seal kit for that and put it in there. Probably a red herring, but it's never a good thing to have a place for fuel to leak out...because if fuel can leak out, air can get in. Interestingly enough, they use rubber seals inside some of those fittings. I would've thought they would've went for brass or just relied on a flared fitting like they do on hydraulic systems. Funny.

- The batteries are good. I have one of those old Milton Toaster battery testers and it stays in the green section during the crank and firing of the glow plugs. They're relatively new batteries, with an August 2007 Date Code on there. Static voltage is 12.6. I never did get it to run today because of that fuel line thing I found, which required a parts trip.

- It does give me a little black smoke when I crank it. Not a bad sign...

- I didn't get a chance to pull the filter today. There is good flow up to the bowl. Pulling the filter is at the top of my list tomorrow, along with checking the rest of those lines for any other goofiness. I probably didn't see it before because of all the dirt that was on the engine prior to my degreasing and removing the valve covers.

In terms of cold here? This time of year, we sometimes get down in the 40s at night, with highs in the 70s and 80s. That ought to make all you up north chuckle!

For blowby, yeah, it has some. Enough to put a little oil in the intercooler ductwork. I don't know what "normal" is for these trucks. There aren't any active oil drips or anything like that. The PCV system is all stock and in good shape.

Again, thanks for everyone's help here. We're still pasting stuff back together on this truck, but at least I've got a few leads now. If anyone has any more suggestions, I'm all ears.

 

Subscribing.
.
You've done all I would have done and expected it to start.
I am interested to hear what the solution ends up being.

 

I've got one in the shop right now also, same thing as yours, except that it's a 3/4 ton. I've checked everything you have, but from what I can see on my scanner, the ECM thinks that the engine coolant temp is -40F, the temp guage works fine and from what I can tell, the guage and the ECM use the same sensor, I've been trying to figure out how this can happen if it's the same sensor, this truck only has the one sensor also. This one won't start at 60 degrees unless you cycle the g-plugs a few times and I'm pretty sure it's pouring the fuel to the engine with all the smoke I get out of it while cranking and right after startup.
If you've got a scanner, check your engine coolant temp and if anyone can tell me why the ECM thinks the temp is -40F I'd like to know also. Thanks!

Travis

 

Travis-

I'm using an old Snap-On Scanner, too. I'm afraid that my Coolant temp readings are right around ambient, though.

I had a look-see at the fuel filter today, which had a little silt in the bottom of the bowl. While we were at it, we pulled the bowl altogether and cleaned the regulator. We also found some more rotted rubber seals on some other fittings. Fortunately, we bought the fuel system seal kit when we went to see the parts department.

While I had the bowl off of there, I decided to take a real good look at the HPOP. There weren't any signs of a leak. I degreased it and pulled the IPR. It was a little yucked up inside, but nothing too terrible. We decided to bench test it to see if the piston moved. It doesn't. So, I'm now waiting on a new IPR. You've got to get that separately from the HPOP anyway.

In terms of the temperature gauge, I see vague references in the manual to a gauge sensor and an ECT sensor just for the computer. The coolant temparature sensor is in the timing case right next to the upper radiator hose junction. That's the one that is supposedly the one for the PCM. I'm afraid I still don't have a clue if there is another sensor or not. I imagine that -40 translates into zero volts.

Best of luck over there in Iowa. I'll let everyone know how things are going once my parts come in.

 

If this turns out to be the solution to the problem, it will translate into a VERY loyal customer. Sending in everyone they know.
It should be good.

 

Well, I put it back together today...the IPR went in without a hitch. As a side note, the bad IPR did not show up with a simple continuity test. We had to go ahead and apply power to it and see if it moved to discover that it had crossed the great divide.

After I replaced all the fuel line fitting seals, I filled up the bowl with clean diesel and refilled the HPOP reservoir (I had drained it in an effort to minimize mess when doing the IPR). It cranked for a wihle longer than I would've expected, caught, and ran like crap for a few mnutes. After that, it smoothed out and ran good. I ran all the diagnostics on the engine again with the scanner, and everything came up clean. Maybe it needed to get some air out of the rails after all that messing around. The only other thing I discovered was that the drain for the V-Valley is obviously clogged. Hopefully I can get a better view of that now that I can move it (hopefully) under its own power tomorrow.

Travis-

I did get the coolant temperature readings as promised. They were showing ambient with the key on before starting. The ECT sensor is on the front of the engine, right next to the thermostat housing. I haven't been able to get a good, solid answer on whether or not there is another sensor for the cluster. I'm inclined to say there isn't, but stranger things have happened, particularly with the diesels. Sometimes IH does funny things and Ford plays along. I'm pretty sure they're all digital instrument clusters in there, though, and they only tell what the PCM commands it to say. It could well be using data from the oil temperature sensor to fudge a readout on the cluster. I don't know the details of the program. Best of luck.

Thanks to everyone on here for your help. I'll keep y'all posted on the final result.

 

Brett,

Got to work on this truck again yesterday(been really busy in the shop, and lots of other things to do), anyway, I have a hunch that my scanner is lying to me--this really pees me off, it's an OTC Genysis, updated to '05 and as far as I know hasn't ever given me trouble before, that pees me off, and also the fact that I broke a cardinal rule....NEVER rely completely on a scanner! Anyway, I'm going to check it out more today, I didn't get much of a chance last night, I may just start all over on this one and hopefully find something I missed. Anyway, thanks for the help!

Travis