I have a 1997 f250 that blows white smoke when it starts. It also takes forever to start it. Battery is strong, turns over good just takes a while to start. What can I do to fix that?

 

Welcome to FTE! Sounds like you have either a bad glow plug relay, or bad glow plugs, or both.

 

Thanks a lot....just changed all the glow plugs...guess I will try the relay

 

Check the under valve cover wire harness plugs for burnt pins also. There are two plugs on each side.

 

Test the relay. You can use a test light, one of the big posts is hot all the time, the other when the key is on. I think I got that right, most here know I'm a little electronically challenged..

 

Welcome to FTE. White smoke at start up is often a glow plug (or relay) issue as mentioned above. Does it re-start any better if you've been driving it around for a while and just shut it off for 30 min. or so?

You can test the relay with a multi-meter or even a test light before you just start throwing more parts at it. There are 2 large posts and 2 small posts on the GPR (glow plug relay). One of the big posts is hot all the time (reads battery voltage). The other one should read 0 with the key off. Turn the key on when the engine is cold, and you should see battery voltage on the 2nd large post for several seconds up to a couple of minutes. If the 2nd large post is dead when the key is first turned on, lay a screwdriver across the 2 big posts to short them together. Hold it there for 30 seconds and then try to start the truck. If it fires up with no white smoke, replace the relay since your screwdriver just did what the relay is supposed to be doing.

What are the outside temps where you're at? We don't usually see to many glow plug issues this time of year.

 

This thread used to be stickied. You may want to read through it.

 

I second ReBilld, most likely some melting of the harness under tha valve cover, buddy had the same problem with his '97.