Glow plug time issue.

[notenuftime]

I noticed in the past couple days my cold starts have changed. I turn my key the wait to start light comes on and after about 3-4 seconds it turns off and my amp meter starts to click. I am use to the amp meter clicking and getting a longer glow time, about 6-7 seconds and good starts. The truck still turns over but with more hesitation and after it's running my amp meter jumps around for a good couple seconds before leveling off. I just replaced the glow plug controller, my GPs are just a year old and new GP wiring harness. I've checked fuses nothing is burnt, I did notice a little wiggle to the 20amp fuse in the engine bay that protects the controller. But im pretty sure it's always had a little play. Has anyone experienced this? Thoughts?

 

[Farmer Rock]

Usually when that happens it means you have 1 or 2 bad GPs.
Easiest way to test them is with a test light. Place the ground clamp of the test light a positive battery terminal, then remove the glow plug connectors and touch the test light to the glow plug and if it is good it will light up.




Rock

 

[notenuftime]

Usually when that happens it means you have 1 or 2 bad GPs.
Easiest way to test them is with a test light. Place the ground clamp of the test light a positive battery terminal, then remove the glow plug connectors and touch the test light to the glow plug and if it is good it will light up.

 

[notenuftime]

Can't imagine ZD-9 going bad just after a year....maybe.

 

[Farmer Rock]

Can't imagine ZD-9 going bad just after a year....maybe.

It is possible. Won't hurt to test them.



Rock

 

[notenuftime]

It is possible. Won't hurt to test them.



Rock

Is there a certain kind of tester I need?

 

[Farmer Rock]

A standard test light probe will do the job. If you want to get real fancy you can ohm them out with a multimeter,but the test light is the most simple way to diagnose bad GPs. A test light like this picture is what you need

You must be registered for see images attach

Rock

 

[notenuftime]

A standard test light probe will do the job. If you want to get real fancy you can ohm them out with a multimeter,but the test light is the most simple way to diagnose bad GPs. A test light like this picture is what you need

You must be registered for see images attach

Rock

So I have a multimeter.
How can I check the plugs with that?

 

[Farmer Rock]

So I have a multimeter.
How can I check the plugs with that?

set your meter to ohms (resistance),place one lead on the block,and the other on the top of the GP with the connector off. should read .8 ohms or less if good.



Rock

 

[notenuftime]

set your meter to ohms (resistance),place one lead on the block,and the other on the top of the GP with the connector off. should read .8 ohms or less if good.


Rock

Does it matter which lead goes where?
Red/black

 

[gnathv]

No, just make sure glow plug lead is disconnected

 

[Farmer Rock]

Does it matter which lead goes where?
Red/black

No, just make sure glow plug lead is disconnected

sorry, it took me so long to get back to you. It looks like @gnathv has got you covered.



Rock

 

[jrollf]

A disconnected and/or loose glow plug lead can do the same thing.

1993 F350 Crew Cab Dually
7.3L IDIT with a Banks Sidewinder
ZF 5-spd manual transmission

 

[david85]

Also check the engine harness connector near the oil dipstick tube. The two thick wires will be for the glow plugs. Any corrosion there can also throw off the reading used by the controller to time the glow time.

 

[notenuftime]

Finally got around to checking things out today. Found two GP leads loose, popped them back tight and started right up. Easy fix and knowledge gained. Next step manual GP switch.