Only cranks after being plugged in

[Dino1191]

Hey guys,

I wanted to ask ya'lls help. I have a 1985 F-250 4x4 with a 6.9.

I just put a new IP in a few months ago from Conestoga Diesel (greatest guy in the world )

recently my truck will not start unless it has been plugged in. I just put a new GP relay on and same thing.

Interestingly enough, when I do not have it plugged in and try to crank, the glow plug light only cycles one time and never comes on again. When I try to crank, it just turns over and over and never fires.

When I have it plugged up for a couple hours, the glow plug light will cycle twice and it fires like a champ every time.

Does anyone have any thoughts?

 

[madpogue]

Does it literally NOT CRANK unless you use the block heater? Or does it CRANK but fail to START?

Have you measured the resistance of each glow plug, and checked the continuity of the wires going to the glow plugs?

 

[Dino1191]

Mad,

It does crank, but, does not start if it is not plugged up. I have not checked the resistance to each glow plug. how many volts should each glow plug receive? Do I check each one with the key moved forward one notch?

Thank you,

 

[shawn deere]

Mad,

It does crank, but, does not start if it is not plugged up. I have not checked the resistance to each glow plug. how many volts should each glow plug receive? Do I check each one with the key moved forward one notch?

Thank you,

Resistance in ohms
Think of glow plugs as a lightbulb- they can burn out. If one is out, your controller wont run very long at all and it wont like to start.
Get a set of zd9 glow plugs if you replace them. Cheap ones can swell up, dont break one off or you will have big problems

 

[pelky350]

If lots of white smoke while crAnking/no start is either glow plugs them selves or relay systems going out but with the short wait to start light is usually sign of glow plugs going out

 

[hesutton]

For your '85 rig, you'll need Motorcraft ZD-1A spade type glow plugs. The ZD9's listed above are for the 7.3 (except '87 6.9's) bullet type connectors and glow plug system.

Heath

 

[shawn deere]

Oops- 6.9s are out of my realm

 

[Dino1191]

Thanks for the notes. Ordering the ZD-1A's and will let you know when they are in.

Thanks again

 

[chillman88]

If you get all the glow plugs changed out and it still won't fire, make sure you have power to the relay... Don't ask me how I know!

 

[Dino1191]

Okay. New relay and new plugs. She starts without being plugged up. However, she used to fire up on the first turn of the motor and now, the starter has to turn over 4 or 5 times before it starts. Also, the glow plug light only comes on one time now.

Thoughts?

 

[shawn deere]

Okay. New relay and new plugs. She starts without being plugged up. However, she used to fire up on the first turn of the motor and now, the starter has to turn over 4 or 5 times before it starts. Also, the glow plug light only comes on one time now.

Thoughts?

Is that when its plugged in it fired right up with bad glow plug vs good glow plug system not being plugged in? - cant beat a blockheater

If its warmish it wont run the glow plugs near as much

 

[Dino1191]

It fired up without being plugged in, but, required a few more turns than normal to start. The glow plug light only cycles one time without being plugged in.

Checked both batteries and both are fully charged and have 13 Volts.

Just wondering why it would take a few more turns to start? Could these symptoms point to the glow plug controller?

 

[chillman88]

Mine only cycles once.... How cold is it where you are?

A block heater will make the whole thing warm so it should start quicker and easier. Glow plugs only heat a small area so the block is still cold.



If you've been cranking for long periods you could possibly have worn the starter some. I had a "newish" starter that when I replaced was a night and day difference.

 

[riphip]

Starter time
DB electric or Powermaster
Needs to turn over faster

 

[lude and rude]

you might have a fuel drain back issue it also... might change out your fuel lift pump if you have never changed it out esp considering they are under 50 bucks. i kind of consider them a maintenance item that needs changed every 25k.