I bought this wonderful 1995 Ford F350 Crew Cab 7.3 PS Diesel truck this summer and as of lately (now that the temps are dropping below 45) I am having one heck of a time starting it. In fact, temps were 26 degrees a couple of mornings ago and it took no-kidding nearly 20 minutes of fooling around with the starting process to get it started. I keep reading that it could be glow plugs, glow plug relay switch or even the possibility of needing a block heater. If I do have to replace the glow plugs and ideas where exactly they may be located? Any other suggestions? Thanks!

:rolleyes:

. This link should help you test your glow plugs:

Free Advice for Diesel Owners.

. Use synthetic heavy duty diesel engine oil; e.g. Mobil 1 Delvac:

Mobil Delvac 1 5W-40

If you install an additional by-pass oil filter, and perform regular Used Oil Analysis (UOA) and change the by-pass filter annually, you could easily keep the oil in for 50,000+ miles. This makes it very cost effective and has been done regularly for years in diesel rigs. There are many other benefits, as well.

. Block heater.

. Clean battery terminals and connections.

. Ensure both batteries are fully charged, after checking fluid levels.

. Purge water from fuel system and change fuel filter.

Colder temps require more to start most motors.
Diesel's will often need just a little more help cold!

Why? The crankcase oil is cold and stiff. And the fuel is cold and stiff.

If the engine and crankcase oil isn't warm, it takes a strong battery to crank it, and if the fuel is cold, it takes healthy glow plugs to start the combustion.

Glow plugs warm the fuel, etc, but the block heater warms the larger machine. Change the glow plugs, and plug in the block heater. If you don't know where on the engine these belong, no offense, but I would recommend you find someone who will be doing this for you.

You won't regret either repair. Both will benefit you.

Diesels do require good strong battery systems for proper starting especially in cold weather.so checking them and assuring this part of your starting sysems is in good operating condition is primary. Your trouble starting coinciding with the cold weather most indicates faulty glow plug system. The glow plugs acually cause combustion of the fuel on start up when the engine is cold. A sensing system determines a cold engine by measuring the temp of the coolant (antifreeze) in the engine. Then the glow plug control circuit is energized sending electrical current to the glow plugs which are located in the engine block extending into the combustion chamber. These plugs cause the fuel/air mixture to burn/explode in the engine. Once the engine heats up, about a minute, the heat generated by the high compression in the engine coupled with the heat already produced by the glow plugs and the engine firing will produce combustion without the operation of the glow plugs. In warm weather these glow plugs operate either not at all or very little and engine startup is easy. Cold weather complicates this as explained above. The glow plugs should be checked individually since they don't usually all fail at once. They are available at auto parts stores as well as auto dealerships, cheaper at auto parts stores. If glow plugs check out OK glow plugs circuit components are the next suspects. Small garage mechanics with a reasonable knowledge of diesel operation can handle these checkout pocedures and they cost less. Hope this helps.

All, thank you very much for responding to my diesel engine cold weather starting issues. I plan to visit a few mechanics today to find out when I can get the truck in to have the glow plugs checked, etc. etc. I did notice it has 2 batteries and now have a better idea why.

For what it is worth, it is true that I probably shouldn't be messing around with this stuff myself as I don't have the knowledge or the tools to do the job; however, thanks to all of you, I can now talk to a mechanic with more knowledge at my finger tips.

I am a computer person by trade so if you have any issues with your laptops or desktop operating systems or applications, please let me return the favor and get you some tips on how to fix your system.

I'll keep all of you posted on my truck repair process. BTW: I did like the idea about the extra oil filter and the thought of replacing the fuel filter as well. I may have to become a grease monkey myself ;) .

Sounds like your glow plug relay needs to be checked first. There are instructions on 7.3 Cold Starts on Hard/No Start? Check here first. - TheDieselStop.Com Forums


Here they are:
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.
· Locate the GPR – Its 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 one of the large posts.
· 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.

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. Photo of disconnecting one and 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.

Hope this helps!
-Nivrat

A Ford Dealership Diesel Mechanic replaced the Glow Plug Relay Switch. Then tested that electrical connection as you described. It seemed to have passed. We will see what happens when the outside temps drop again. If I continue to have issues then the glow plugs will be checked next. If it isn't too much trouble and I can find the tools, I wouldn't mind testing the glow plugs as you described. Thanks for the mechanical education. I could save myself a ton of money if I could do some of these repairs myself. The relay seemed like an easy item to replace. Do you have any tips on replacing some of the small hoses such as the power steering hose? It appears that a lot of the hoses are getting hard, dry and brittle. I guess it would be best to get bulk hoses; then, I can just cut the lengths off a role. Additionally, I don't want to lose a bunch of fluid. Again, Thanks.

I have found that for P.S. hoses as well as rubber brake lines, it's sometimes easier (and the most economical) to buy replacement hoses. These hoses have special ends/fittings that are best left to the professionals to put together. This website TheDieselStop.Com Forums - Powered by UBB.threads™ is FULL of people who have many years experience working on their 7.3 Fords.
-Nivrat

This has happened to me many times with my 1990 7.3 idi I had to change the glow plugs once a year. And I also changed the harness and relay because they were the original ones. That's were I would start.

I just replaced the Under Valve Cover harness on the drivers side due to loss of power. It fixed my problem! I also bought a second harness (they fit either side!) so when the passenger side acts up I will have it on hand.

The glow plugs can draw around 160 amps. The relay will go bad. If you get a new relay use the one from Ford. The parts house relay is to light duty.
You should be able to hook a trouble light to the output of the relay and turn on the key to see if power is going to the plugs.

Does anyone live near Troy Michigan that would like to make a couple of extra bucks to take care of my F350 7.3 cold starting issue?

sammysam, see if these links help:

https://www.askmehelpdesk.com/cars-t...ml#post1415281

https://www.askmehelpdesk.com/cars-t...ml#post1985158

Will this also cause a gray cloud of smoke when cold starting?

spike012, white (gray) smoke is a sign of water vapor or fuel that has been atomized, but not burned. Water vapor may be present in the fuel, or water may be leaking into the cylinders from the cooling system. Also, air in the fuel can cause white smoke. White smoke usually occurs when there is not enough heat to burn the fuel. The unburned fuel particles go out the tailpipe and typically produce a rich fuel smell. It's not unusual to see white smoke in the exhaust, during cold weather, until the engine warms up. Bad glow plugs (burned out, coated with carbon, or not receiving proper start-up voltage) or a faulty glow plug control module can cause white smoke on engine start up. Low engine cranking speed may also produce white smoke. If white smoke is visible after the engine has warmed up, the engine may have one or more bad injectors, retarded injection timing, or worn injection pump. Low compression can also be a source of white smoke.