My Nephew has a < 90k mile 1994 7.3 Turbo Diesel that does not want to start. Batteries are less than a year old, battery cables look good, cranks fast but does not want to start 40* temps.

So far, we changed the glow plug relay but it did not fix the problem. I suspect the glow plug controller has a problem but I know little about this system. Other advice given was change glow plugs but this seems unreasonable to me. Appreciate any advise.

 

Check out the FAQ and the stickies, TONS of information on the glow plug systems and how to test and repair them.

 

Either the controller is bad or the glow plugs are bad.

I put all plugs in my truck, still wouldnt start in cool temps, found the controller power wire was unhooked. Replaced it, figured it was unhooked for a reason

 

it could be a bad controller, disconnected controller power wire, disconnected controller ground wire, or bad glow plugs. what type glow plugs are in it? if they are not motorcraft ZD-9's, my bet is they are probably bad and there is nothing wrong with the controller.

 

Sorry about not seeing the FAQs. I searched the site using 7.3l turbo diesel glow plug controller, nothing came up, so I jumped on posting.

The truck has the factory original glow plugs and controller. It has about 90k miles. I will read through Faqs and see what I can figure out.

 

Does your wait to start light come on? Mine did but just for a few seconds. After I replaced the controller it started just fine. Of course this was after I solved all of air intrusion issues first.