The Diesel Stop banner
1 - 20 of 31 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
Have a 2000 f250. Its smokes like crazy on cold starts. Smells like unburned fuel. All glow plugs are good. Smokes for like 10mins or until the temp gauge gets last the C point. If I plug it in, it won't smoke at all. New to diesels, I almost wanna think I have a leaky injector. Anyone else have any thought as what it could be or more ideas what I can do to trouble shoot. Any help is appreciated, thanks.
More info about my truck. It has 255k miles. And its stock as far as I know. It has a cold air intake, and a boost gauge. 50-80mph with foot to the floor, its pushing 25lbs of boost.
 

·
Registered
Joined
·
1,815 Posts
You state that your glow plug are all good....how about the glow plug relay ??? Is it 12V power getting power to the glow plugs thru the relay ??
If your plugging it in and it starts much better its because the engine is nice and warm and it's not needing the glow pugs (as much) to start.
If your not getting much throttle response once started and cold it might be because your exhaust back flow pressure valve is closed trying to help in warming up the engine to a good operating temp. The valve opens when your PCM (computer) sees that your engine is up to operating temp.

Where are you located ??
Whats the outside temp ??
 

·
Registered
Joined
·
1,815 Posts
You Tube is great for watching videos on how to check lots of issues on the 7.3L, I'm not the best at explaining things thru the keyboard.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #5 ·
I'm located in new York. I think its around 30 degrees in the morning. Tomorrow morning, I have a temp gauge camera type thing an I wanna get the temps off the exhaust ports an see if I can see a major difference in heat
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #6 ·
The glow plug relay looks fairly new so I wanna say its good. But I'll check it tomorrow. Don't have my meter with me
 

·
Registered
Joined
·
1,815 Posts
Looks can be deceiving !! Even new relays go bad. If you don't have a meter to verify that voltage getting across the big studs when the key is first turned.... you can you can try this and see if it helps and it may answer the question as to is the glow plug working. It could be the coil is bad not pulling in the relay or no voltage to the coil or no voltage across the contacts, but the below trick will help get it going easier.

With EXTREME CAUTION you can use a screw driver that has a nice insulated handle and short/touch the two larger glow plug relay studs to each other(without touching anything else with the screw drivers metal shaft) for 30-45 seconds then have someone or yourself try to start it and see how it starts. The glow plug relay stays on for longer than 45 seconds when its that cold out and the engine starts, but it'll be enough to get it to start nice.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #9 ·
Update: jumping the glowplug relay didn't help the smoke. With my thermo gauge, Startup I'm getting roughly within 30secs its up to 120-40 and I'm read 3 out of 8 cylinders are reading about 80-100°. Does that tell you guys something about to.much fuel in the cylinders?
 

·
Registered
Joined
·
1,436 Posts
Update: jumping the glowplug relay didn't help the smoke. With my thermo gauge, Startup I'm getting roughly within 30secs its up to 120-40 and I'm read 3 out of 8 cylinders are reading about 80-100°. Does that tell you guys something about to.much fuel in the cylinders?
How did you confirm that the "glow plugs are good" ?

Jumping the relay should have powered all 8 plugs although your temp readings indicate that 3 of the 8 cylinders are not heating up quickly.

If the truck drives fine once warm I wouldn't go after the injectors just yet until you can confirm everything is good from the relay, harness, and individual glow plugs.

FWIW I've seen glow plugs that have ohm'd out fine but when you hook them to 12 volts they don't glow 100%
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #11 ·
I will check ohms in about an hour. How can I tell if they are properly glowing 100%? Take them out? Would glow plugs make that much smoke come out?
 

·
Premium Member
Joined
·
7,934 Posts
Ok so here's the deal on some glow plugs out. If it starts, those cylinders with plugs out are still getting sprayed with fuel. Shortly there after with the rpms being at idle, the pistons are now making more heat than they do cranking at 150 rpms. This heat is suddenly sufficient enough to ignitite an injection event or multiple with split shots. Anyway it starts lighting off and burning of unatomized unhurt fuel from the earlier injections at cranking that never combusted. This makes smoke but clears shortly after that cylinder us making enough heat on its own without glow plugs due to the increased compression it has from turning at 650 vs 150. IF this combustion chamber is not capable of making adequate heat on its own at 650 rpms, it will continue to smoke as its only capable partially burning fuel.
Injectors incapable of delivering atomized fuel with smoke as well.

Go out and put your keys in your pocket. Jump the starter relay on passenger side fender after making sure truck is in neutral or park. Post video of you cranking five full revolutions at engine compartment. Would like to hear how even your compression beats are. No keys in truck.
 

·
Super Moderator
Joined
·
26,502 Posts
Another possibility is the condition of the oil. If it's overdue for a change, the injectors may not be firing correctly until the oil warms up. The PCM is supposed to increase Injection Pressure (HP oil) when the engine is cold to compensate for the thicker oil, but if the oil is flat worn out, that doesn't work as well as it should. Injection timing is also advanced a bit with a cold engine (measured by the Engine Oil Temp sensor).

It could also be that you have some injectors that are needing attention (worn out).

You can try some of your favorite fuel additive, or drain the fuel filter bowl and fill it with Seafoam, then replace the cap and run that thru the injectors. That will sometimes free up sticky injectors.

An easier (maybe safer than a screwdriver) way to short the glow plug relay is to use a pair of jumper cables between the battery hot terminal and the downstream terminal of the GPR. That way you can leave it clipped on and then go start the engine. Also avoids having to mess with the rubber boot over the hot GPR terminal and potentially screwing that up. The GPR should be pulled in for nearly 2 minutes at 30F oil temp (which may be higher than ambient temp if you haven't let it sit overnight).

Nick's suggested crank with the key off is a rough indication of compression on all the cylinders. One cylinder that sounds like it doesn't drag the starter down as much as the others indicates that it's low on compression. A low compression cylinder will not fire as efficiently as one that's up to snuff, and will generate that eye stinging smoke. The trouble with that test is that it doesn't pinpoint the problem cylinder. Your temperature gun test on the exhaust ports is an indication of which cylinders aren't firing well.
 

·
Premium Member
Joined
·
7,934 Posts
But it can give you an idea or confirm a suspisicion before doing a bunch of tests and taking covers off and doing a more in depth compression tests. It's a great easy couple second test.
 

·
Super Moderator
Joined
·
26,502 Posts
But it can give you an idea or confirm a suspisicion before doing a bunch of tests and taking covers off and doing a more in depth compression tests. It's a great easy couple second test.
I agree fully Nick. I was just pointing out that it's not a definitive test. It is easy to do and a good preliminary test to point you in the proper direction.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #16 ·
It won't let me upload the video. Just says uploading then stops an nothing comes up. An I did an ohm test an I'm getting some crazy readings. I took the valve cover off. Gonna take the glow plugs out an do a test on them when there out so I can get a clear Reading.
 

·
Premium Member
Joined
·
7,934 Posts
No, take it first at valve cover so you are taking into account the pins in the gasket and the wires. You can buy a Dorman pigtail at the parts store to plug into connector. This will make getting at those pins easier.
Have you done the voltage drop on the relay yet?
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #18 ·
Another update. On the driver side. 3 out of 4 glow plugs were working an I'm pretty sire it was on the same cylinder that was about 20° colder on cold starts. So now the passenger side looks like its gonna take a lot more to get to the valve cover but I'll do it tomorrow. Thanks guys for all your input. I'll let you know what I find out
 

·
Premium Member
Joined
·
7,934 Posts
You will want a 13 mm flex head socket will a 6 inch extension and a shorter one. Get a Milwauwake 3/8 drive cordless ratchet from Home Depot or Amazon if you can swing it. Once you are back there, you will wish you did.
Use Motorcraft or DieselRX glow pugs.
Ideally you would want to take compression readings while in there.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #20 ·
Another update. Passenger side had 3 bad glow plugs. Hopefully its just a gkowplug problem. Next I'm gonna have to learn how to use this new meter I bought. I tested them all before an I swear they showed out good ohms.
 
1 - 20 of 31 Posts
Top