Do I have to drop the engine for glow plugs?

[TheArgobus]

I've got a 95 E350 with the 7.3L, and the glow plugs don't work. I'm about 100% certain it's the relay because when I turn the key to on, I hear no clicking, no sounds, no nothing. So I picked up a replacement 200 amp relay but I can't seem to find where the relay is located.


There's a lot of videos out there showing how to replace the relay, but those are usually on trucks and the relay isn't located in the same place on my bus.



I removed the air intake and looked around and behind the alternator, but still... no relay could be seen.



According to the "Care and Feeding of the 7.3L" thread, the relay is located under the passenger side valve cover. So I pulled the engine cover off and quickly realized there is no possible way I could remove the valve cover with the engine in place, as the firewall prevents me from accessing a few of the bolts on the forward end of the valve cover.



Now, dropping the engine is something I only heard of in my search for the relay, and it is certainly beyond my capabilities, so I'm leaning towards bringing it to a shop to do it for me.


Does this sound correct? Am I misunderstanding some core concept here? If I do have to drop the engine, is there anything else I should add/install while it's accessible?

[brokedown]

Not sure where the relay is located but it should be relatively easy to trace. Start from your most accessible glow plug and follow the wire back. On my T444E Vista it was on the drivers side next to the engine, roughly on plane with the front of the block... But I wouldn't expect that to be a universal thing.

[TheArgobus]

How easy was it to access? I think I see some sort of relay potentially right behind the drivers headlight/in front of the main battery but there’s a lot of wires attached

[brokedown]

The glow plug relay should have 4 wires. 2 big, 2 small. if you suspect the relay is bad, you can use a plastic handled screwdriver to bridge the two big terminals for 10 seconds or so to manually heat the glow plugs. After that you've got just a few seconds to try to start the bus before they're cold again, so it's best to do with a fiend sitting in the driver's seat.

[brokedown]

Anogher quick note. There are several types of solenoid but they are not equal for this type of task. A lot of folks have gone to NAPA to get a replacement glow plug relay and used their popular GPR109 of GPR110 (https://www.napaonline.com/en/p/ECHGPR109). Those relays are rated much higher than their actual capability, and they will fail almost immediately on a 7.3. I tried one and mine lasted literally one day. Similar looking relays from other vendors won't be better.

What you want is a solenoid rated for at least 100A, continuous duty, with an isolated coil. The 7.3 will pull a lot of juice and keep pulling even when the "wait to start" light goes out... As much as 4 minutes even after you've started the engine.

THis is the relay you want if you don't want to end up stranded: https://amzn.to/2XFcUqJ

[PatrickBaptist]

Pulling a 7.3 out of a E series van platform is horrible, without pulling the body off you get to take off the oil pan, oil to water cooler, fly wheel, and starter before you can beg the engine to come out the nose of it. Then to shove it back it it gets even more insane, fitting the oil pan on the engine while it's jiggling around hanging by the hoist is so awesome.
Been there and played that game, it's a royal nightmare, never done one on a short bus but have on a 1 ton van and the GP relay was in the same spot as on the trucks....
Whatever you do don't use starting fluid of any kind, great way to ruin these, bought several that were "addicted to the idiot spray", generally because the noob owner thought it was wiser to start them like a detriot than to replace the GPs.

Lastly though, I've also done GPs in a E350, the valve covers will come off, it's a big pain but the engine doesn't have to come out for it.

[cadillackid]

Ive always seen the GP relay behind the fuel bowl.. it is Near the passenger side valve cover but def not under it,, the bracket for it may be attached to one of the bolts for that valve cover..

[somewhereinusa]

Test the relay, with a test light on any glow plug and do whatever is supposed to cycle the glow plugs. If it lights relay is ok.