For a while my 94 7.3 idi was doing great this winter. I was so proud of her. I would be able to plug her in and start on the first try in 20 degree weather.

Now, however, it is staying around 30 degrees for a few days, and she isn't liking it.
It will turn the starter strong and fast all you want, but she just won't fire up, whether plugged in overnight or after sitting during school.

So what went wrong??
Do i need new glow plugs? Injectors?
Replace the block heater?

I have resorted to using starting fluid the last few times, which i know is awful for the engine, but I don't know what else to do. Help!

 

Honestly it sounds like your block heater is not working anymore... Easy way to check if it is... Is plug the truck in and after an hour or more feel the engine especially around the radiator hoses/coolant passages... If its not warm then its not working

 

Check the following for info on testing your glow plug system:
https://www.ford-trucks.com/forums/9...le-system.html

Also, if you use starting fluid make sure the glow plugs are disabled and cold, otherwise you risk destroying the engine.

 

Any chance it could be the fueL filter causing this? That light is coming on the dash, but i always thought it was more of a recommendation.. Me being dumb as usual

 

yes it could be a bad fuel filter, or air intrusion.

 

The truth is, that cold can highlight any number of starting issues.

Aging lift pump, IP, injectors, glo plugs, and so forth.

You running a fresh fuel filter? How many miles on the injection pump?

Roy

 

irhunter is right. before you start throwing money and parts at it, 99% of hard starting is glow plug related. the fuel filter light comes on when the ip pulls on the filter with enough suction to activate the switch, this normally indicates a blocked filter, or bad lift pump, carefully check all functions of the glow system as it only takes one bad connection to ruin your morning.

 

"fuel filter" means the filter is plugged.could be gelled fuel.when this light comes on,the only recommendation that light has to give you,is an engine that wont run.

 

He's saying 30*F, and I am not sure that is cold enough for jelled fuel...but, there is just about zero down-side to adding anti-jel right now. White-jug Power Service, used at the rate specified on the jug, works well for me.

Roy

 

I would say that if you had to plug in at 20 degrees, you had issues with your glow plugs before any of this started. I could start up my old '85 in 10 degree weather after it had been sitting for a week in the snow, and it would crank up first try after glow plugging it for 15 seconds and no block heater at all. Granted, I had Motorcraft plugs and a brand new return line kit on it, but I still never had a problem with it starting up.

 

The light could also mean that that wire is loose and sitting in a puddle of leaked diesel... <_<

Just so you know, when the engine is cold, you can safely use a /little/ bit of ether(1-2 second squirt), but let the GPs cool down for a few seconds before spraying and starting.

Also, everyone talks about engines becoming addicted to ether, but it's really the other way around -- engine wears to the point that you /need/ ether to start it.
I've had an engine that the PO could not get to run without ether, and used it for years that way. I fixed the GP system and timing, and it started up great without it(above 10F or so, at least). Recently had the engine rebuilt, and it was mechanically intact, but lots of bore/ring wear -- lotta miles on that engine.

 

No, engines DO become addicted to ether because it sticks to hot glow plugs and then they burn out. When ether becomes necessary, it's because the original system isn't working right. The glow plugs take a few MINUTES to cool down, not a few seconds. They're burning at almost 900 degrees, that kind of heat doesn't go away quickly. If the fuel injection system is well taken care of, and not left to be a neglected piece of crap just because it's an "old truck", then they should start just fine the way they are designed to down to almost 0 degrees. Air in the return system and bad glow plugs are almost always the two main culprits on why these engines don't like to start "cold".

 

Uh... there's a few logical problems with this:
First, I don't see how ether(or even oil, for that matter) can stick to a glow plug. The high temps will burn it off.
Glow plugs burn out over time, especially when the controller isn't working quite right... and after 25 years, they usually aren't(grounding issues, I think).

Yes, I agree with this. Though if you've got a worn engine(low compression), the original system, working perfectly, may not be able to do it when the outside temperature is low.

Actually, having played with a glow plug myself, they heat up really quickly and then cool down at about the same rate. That GP will drop to under 200 deg within a minute if it's not powered. This is why the controller cycles after the initial on time.

Depends on the compression. But generally, you're right. That being said, the reason most of us are driving such an old truck is because we don't have the money to fix it /right/.
It's not air in the return system. The return system does not matter at all -- that's /after/ the IP, and mixes with leaked fuel coming /out/ of the injectors.
Air intrusion is when air gets into the /intake/ side of the system, usually at the filter head, and means that the pump needs to pump fuel all the way back up and into the IP.
This also usually manifests as an engine that starts right up, then dies.

Bad GPs are indeed common, along with marginal GP controller systems.

 

Not exactly....
This is more like it. The fuel filter switch is a vacuum switch. A little over a year ago my fuel filter light would come on sometimes on the highway, definitely when towing. About two weeks later the engine stalled out just after going through an intersection. The lift pump fell apart when I removed it.

Test the lift pump by checking the flow at the schrader valve on the filter header. should be 1/3 pint in 10 secs of cranking (if I remember that right). I'm pretty sure the valve is on the incoming flow, before the fuel goes through the filter. So if you have good flow there, change the filter (if it hasn't been changed in a while, might as well just change it anyways). If no fuel, or not much/no pressure, check the fuel system.

Have you checked the glow plug system yet?

 

geez 30 f it should fire right up. must have a fuel issue forsure. maybe its 1/4 tank and the foot fell off the pickup tube.