93 F-250 7.3 IDI Turbo 5 speed 2wd single cab long bed

Replaced glow plugs about a month ago. Truck was starting great. One morning I tried to start it but I had to crank it over several times. Acted like the glow plugs were not heating.

Wait to start light comes on for 10 seconds or so. I checked the relay with a test light. Had power on the ignition terminal and battery terminal of the glow plug relay. When wait to start was on, had no power on the stud that goes to the glow plugs.

Changed relays by following the information in the glow plug sticky at the top of this forum and am still having the same problem, no power to the glow plugs.

I have verified that my grounds are good on the relay, the white and black wires.

What should I check next?

Thanks for the help.

 

did you replace the whole controller or just the relay, is yours the one behind the intake? If so then your problem should have been the relay but if that didnt cure the problem, you need to take the controller system out and have a good look at it. Just for fun can you please check the voltage at the glow plug connector by using a multimeter or test light? That would help.

 

Did you use an 86 glow plug relay?

Did the parts store give you a glow plug relay or a starter relay?
By the small terminals do you see an S and I labeling the terminals?

When you turn the key to on, does the relay click?

 

NAPA gave me a starter relay, the one with the I & S terminals. Hooked ignition wire to the "S" terminal. White wire is moved to the mounting post for the relay. Nothing is hooked to the "I" terminal.

Battery wire and glow plug wires are connected according to the pictures in the Glow plug sticky.

I have verified that there is power to the battery wire and ignition wire when wait to start is on. The light stays on for 10 seconds or so. However there is no power on the glow plug stud on the relay.

I do not have a multimeter available to check voltages at this time. I wish I did. I may be able to check them at work tomorrow.

Also, I do not hear a click from the relay when the key is turned on.

Thanks for the help thus far.

 

sounds like the power in the truck is screwy, that power relay is a starter relay too. Mine worked fine so dont worry there, just make sure power is going to it and that the wires are not backward, corroded or grounded somewhere.

 

The gp relay is a starter relay too?

 

They look identical, but I have been told they are different internally. I was told a starter relay uses a bar to make the connection and over time it begins to stick. A GP relay has a disc that rotates and has more usable surface making it last longer than a regular starter relay. Thats what I have been told anyhow, not sure how true it is though as I cant remember who told me.

 

first off, a starter relay is no good. it will burn out from the high amperage the glow plug circuit requires. you need a glow plug relay.
second thing. you say you replaced the glow plugs a month ago.
what type glow plugs did you use??
if they were not motorcraft/beru, i bet they are burned out already. 99.9% of the glow plugs that are sold by parts stores are pure garbage that should be thrown away before they are installed in the engine to save you the trouble of replacing them again.

 

well tjc pretty much summed it up

 

So the glow plugs could be bad already? They are the crappy autolite plugs so I bet that's the case.

I thought the wait to start light would not stay on if the plugs were bad.

I do get a 10 second wait to start light.

 

I thought the WTS light was just on a timer. My WTS light stayed on the same amount of time when I had bad plugs as it does with my new plugs. I have an extra light in my dash connected to the relay that tells me when the plugs are actually getting power and it stays on much longer with the new plugs.

 

I'm not really sure. I know when my plugs went bad the light would only stay on for a few seconds.

So I guess the next step would be to test the glow plugs and see whats going on there?

 

autocrap glow plugs will burn out within 2-3 starts usually.
if you only get a 10 second WTS light, you have 2-3 plugs that are bad.
here is a site for real glow plugs that you will not have to worry about for another 10 years after installed, and they cost less than those garbage autocrap plugs too..

7.3 Liter Diesel Motorcraft Glow Plugs - Ford 7.3 Liter Diesel Motorcraft Glow Plug

 

I have an extra set of 8 Motocraft/Beru ZD9 plugs that I would like to part with. New in package.

 

Check out some of the stuck glow plug threads then remove all of the autolites bad or not before you have major issues with major bucks involed.