My son has an older ford 93 diesel 7.3, it has a hard time starting when it is cold, works great when plugged in. New glow plugs this past weekend. They just dont seem to heat up. Is this the glow plug modulater not working?

 

Check the glow plug relay probably shot. Were always changing them in our work trucks.

 

On the old 6.2s we used to just bypass the controler and run a push button instead. No more fussin with the faulty controlers in the cold.

 

i had a '95 and put 4 relays on it in 2 years.... don't buy them from the dealer, go to napa or auto zone

 

I second starting with a new glow plug relay. We just replaced one on our 97 Powerstroke same problem slow start when cold. We have two Powerstokes and I have been getting 75,000 to 100,000 miles out of these relays before replacing. I replaced the glow plugs on the 95 at 160,000 and feared they would be coked up. I found them clean and tested good with an ohm meter.

 

Thanks for the info guys, they want almost $300. up here for the relay.
Our diesel mechanic from the Fire Station gave me a second hand one too trouble shoot with. will try it out in the morning. and then I will have to shop around.

 

Simple way to solve the problem is get a switch that will return to the off position and mount in down near you knee. Go here for details.

http://forums.thedieselstop.com/ubbthreads/

 

I thought I had to change the whole thing,module and relay, turned out it was just the rely and was only $18.00
Thanks again for the help guys