No start when it’s a cold start

[Abz Stract]

I have been having issues with my 7.3L not starting as the temperatures drop - like into the 40’s (currently 41).


I have assumed it’s because I do not have a block heater and it sits more than drives.

This time I thought I had it. I was home, I knew the cold was coming and so I started it for the past three days. All good - running fine. Tonight the lowest night of 41 - it’s starts - I did it! - for it to run a few seconds and **** off.

I didn’t try it again, it will be warm again in a few days.

It is to warm for the diesel to gel.
Everything should have been warm and moving because of letting it start and run everyday.
Batteries are new and it started right up.

What is getting cold and causing this?

[nikitis]

Glow plugs could be shot. It's supposed to warm the diesel fuel for cranking. This doesn't seem to be occurring for you. Glow plugs should be able to warm it in 40'ish degree weather.

I'd start there.

[jazty]

The stock glow plug relays are known to crap out, causing hard starts when the temperature drops.

If you search for "7.3l glow plug relay" you will find many leads

[cadillackid]

Originally Posted by nikitis

Glow plugs could be shot. It's supposed to warm the diesel fuel for cranking. This doesn't seem to be occurring for you. Glow plugs should be able to warm it in 40'ish degree weather.

I'd start there.

my 444E starts in -15f with all its glowplugs working..
forst thing to check is the glowplug relay ..



the OP doesnt say much about whether his 7.3 is the t444E or an IDI..

if its a 444E the glowplug relay is a mini starter-type solenoid on the top of the engine neasr ther middle.. when the key is on "wait to start" there should be voltage on both large terminals from each to ground..

[Omnibot2000]

And if you need the relay and have the funds, use this one.

Way over kill but will likely be the last one you need.

I use to change mine every 18 months on my OBS 7.3. Been 4 years now and still going

It is bigger, so some mods need to mount it but no regrets.

[cadillackid]

Originally Posted by Omnibot2000

And if you need the relay and have the funds, use this one.

Way over kill but will likely be the last one you need.

I use to change mine every 18 months on my OBS 7.3. Been 4 years now and still going

It is bigger, so some mods need to mount it but no regrets.

these are continuous duty.. the regular ones are not... ive heard of people cracking the regular ones by continually re-keying the glowplugs during a hard super cold start..

[Omnibot2000]

Originally Posted by cadillackid

these are continuous duty.. the regular ones are not... ive heard of people cracking the regular ones by continually re-keying the glowplugs during a hard super cold start..

I don't rekey my glow plugs. I will wait an additional 5 seconds after the light goes out. You can see the glow plugs on by the volt gauge. They stay on after the engine starts anyway after some time.

I even replaced all my glow plugs with Ford OEM. Still burnt out a relay afterword.

I have taken them apart after replacement. The contacts on the inside are burnt causing alot of resistance. One could clean the contact and rivot the bottom metal plate back on.

Alot of Ford guys change over to that white Rogers relay. If you look at the reviews on Amazon you can see that.

[cadillackid]

Originally Posted by Omnibot2000

I don't rekey my glow plugs. I will wait an additional 5 seconds after the light goes out. You can see the glow plugs on by the volt gauge. They stay on after the engine starts anyway after some time.

I even replaced all my glow plugs with Ford OEM. Still burnt out a relay afterword.

I have taken them apart after replacement. The contacts on the inside are burnt causing alot of resistance. One could clean the contact and rivot the bottom metal plate back on.

Alot of Ford guys change over to that white Rogers relay. If you look at the reviews on Amazon you can see that.

on mine they will go off if the start fails or the engine dies.. I never have failed starts but sometimes ill have a start and surge then die once and have to restart...



but ive been with people in the fords where they just keep having failed starts or where it dies and wait the whole cycle.. i do notice when mine starts that the plugs stay on like 30 seconds or so afterwords.. I dont know how ford does it..

[Omnibot2000]

Originally Posted by cadillackid

on mine they will go off if the start fails or the engine dies.. I never have failed starts but sometimes ill have a start and surge then die once and have to restart...



but ive been with people in the fords where they just keep having failed starts or where it dies and wait the whole cycle.. i do notice when mine starts that the plugs stay on like 30 seconds or so afterwords.. I dont know how ford does it..

Almost appears to be the same logic for the Ford's. Key on, wait to start lite comes on, then goes off. Start engine and runs. I can watch my volt gauge while it's running and the glow plugs are still on for about another 30 seconds.

My engine is starting to get a little tired so I'll wait another 5-10 seconds after the light goes out before attempting to crank it over and starts every time.