Why won't my 7.3 start without starter fluid at altitude?

[kccourtney]

Hey y'all. Just wondering if anyone can shed light on this. For quite a while our '99 7.3 van has a hard time starting at altitude, in the cold, and obviously those two go hand in hand. Anything above 5000' and I better bring some starter fluid with me. She'll start up okay in the middle of the day if she was running a couple hours ago but in the morning at around 7000'-8000', forget it.

Lately, it's actually shown a bit of a struggle just starting at sea level if she hasn't been running for a day or two. Nothing major, just takes a couple seconds longer than it should to fire up. I'm not an engine expert but figured it was either glow plugs or (god forbid) injectors. Air filter's totally clean. I'm thinking that since she'll start when it's warm, that maybe it's the plugs or maybe the heating element that is supposed to kick in when you turn the key to "acc" isn't working. She's only got about 150k in the rear view mirror so, relatively fresh. I'm not super put out by using starter fluid a handful of times per year but we all know it's not great to make a practice of it. Besides, I want to get to the underlying issue.

Anyhoo, I know there's a lot of folks on here with grease under their nails so if you have any insight, I'd appreciate. Thanks in advance.

 

[Last Frontier Wrangler]

The 7.3 has a relatively weak Glow Plug Relay, which may make cold starts difficult if it is not providing enough power to the glow plugs. dieselorings.com sells a beefier relay that may solve your issues. Im no expert, so this may not be your issue, but I know it solved my no cold start issues.

http://www.dieselorings.com/1999-20...-stancor-586-902-monster-glow-plug-relay.html

 

[AYIAPhoto]

The glow plug relay is rather easy to test, though the glow plugs themselves are a bit harder in a van than a pickup due to the tight engine compartment.

Relay: With the key OFF, using a volt meter grounded to the chassis, one side of the relay should read battery voltage and the other should read zero volts. You want to test the zero volt side. With the engine stone cold, have someone turn on the key while you watch the meter(you should also be able to hear the relay click on). It should go up to battery voltage for 30 seconds to 2 minutes. Generally in colder weather it will stay on closer to 2 minutes. If the relay comes on and then turns off quickly, the relay is likely bad. You can do this test with a simple test light, but you can only time the relay and not be sure of its output.

Glow plugs: You will need a DVOM(digital volt ohm meter) to test the plugs. There are electrical connections on the side of the valve cover gaskets. Disconnect the harness from one gasket at a time. On the valve cover side of the connection there will be 8 pins. The first 2 and last 2 are for the glow plugs, the middle 4 are for the injectors. Set your DVOM to read Ohms and again attach the ground side of your meter to the chassis. Test each of the 4 outer pins for resistance. They should read between 0.8 and 1.2 Ohm. Any lower than 0.8 and you have a bad glow plug.

Here's hoping it is only the relay. As I mentioned earlier, the tight confines of the van engine compartment make diagnosis of the plugs difficult. Removing the valve covers to replace them is even harder.

 

[Heloflyboy]

Do you have a block heater? I live at 6200' and without it being plugged in for a couple of hours my 7.3 van will not start. I have 3 bad glow plugs, I have just been waiting for winter to finally be over to change them all.

 

[WOODY2]

I'd be very careful with the starter fluid, in years past it caused the glow plug ends to mushroom thus preventing easy removal/replacement

 

[Bikersmurf]

After installing a 'Monster Glow Plug Relay' my cold start (even at altitude) issues went away. The original had cracked in half and at the slightest drop in temperature and it'd struggle to start. Now it'll start in bellow freezing temperatures at the ski lodge.

 

[Vetter]

If using starter fluid, it is very wise to disconnect the glow pugs first at the relay, I know it's a pain, but if the starter fluid ignites on a upstroke it will easily break things. Don't get me wrong, I use starter fluid all the time on my tractor, just make sure there is no ignition source to ignite it, only the compression source from the engine.
Does it blow a lot of white smoke before starting? If so, these 7.3's are known for air leaks on the fuel lines, which will cause hard starting when sitting for a while.

 

[kccourtney]

Thanks so much guys. Some poking around led me to the GPR multiple times and it sounds like the easiest thing to check and relatively cheap. I'll start there and move on to the plugs themselves if no improvement. Again, really appreciate y'all's input.

 

[JPutnam]

I am currently putting a new block in my 7.3 van. the previous owner used starting fluid all the time and I used it a few times. the diesel shop I took it to said the starting fluid blew the piston rings in cylinders 3 and 6. Claimed they see it all the time with the 7.3s that have had starting fluid used. I would stay away from it 100%. its not a cheap engine to replace or rebuild. wasn't cheap to have a compression test performed either. I would just buy all new glowplugs. that beffier relay and pray it fixes it. if not then youre looking at injectors. that's what I did on mine before blowing the engine. ended up being 2 bad injectors. Im not mad that I replaced the glowplugs and the relay. Just means I shouldn't have an issue with them for a good while. good luck.

edit: also check the valve cover gasket wiring. Friend of mine had some oil get in a ruin the wiring connecter on his causing his glowplug wiring to not work or something. he changed his valve cover gaskets and it fixed it for him.

 

[Missiongravity]

On my previous 7.3 I had hard start issues that got worse over time. Turned out to be injector o-rings. They had gotten brittle over time and started leaking thus making it tougher to build fuel pressure at start up. May be worth looking in to.

 

[Deshet]

You should be able to cycle the glow plugs two or 3 times to get it to start even with a couple of bad glow plugs. Although the light goes out the glow plugs can still work for 120 seconds depending on temps. Cycle them on and off multiple time and it will start. (wait at least 100 seconds between cycles)

The starter fluid can cause damage and blow your intake. Weak batteries can cause some starting issues but it is likely the relay. If you replace the glow plugs, go with international or motorcraft plugs. They can be found online for fair prices. My local international dealer is close enough to online prices that it isn't worth waiting on the shipping.

 

[truck mechanic]

worn injectors can also cause a hard/no start when temps dip.

 

[kccourtney]

So I got the new relay but can't find where it is in the engine. Everything online only shows it in an F-series. Anyone able to steer me in the right direction? Thanks in advance.

 

[AYIAPhoto]

In the valley between the cylinder heads on the passenger side. You will need to go in through the doghouse to reach it, and it's a little tight. Here it is on an F-Series(pickup), but it is in the same spot on the vans. You may also have to remove the charge pipes from the turbo to the heads for a little more access room.

 

[Drizzt]

In the valley between the cylinder heads on the passenger side. You will need to go in through the doghouse to reach it, and it's a little tight. Here it is on an F-Series(pickup), but it is in the same spot on the vans.View attachment 402902 You may also have to remove the charge pipes from the turbo to the heads for a little more access room.

Not sure which is easier, but I changed mine from the front. Removed the air filter box and alternator to reach it. Working on van engines always requires some gymnastics...