Need to wait for the WTS light?

[johneich]

My truck has been starting real good with the new IP, injectors & Carrier pump. So good that I once forgot to wait for the WTS light, the truck fired right up on a 70 degree day.

Can I just turn the key to start on warm days or do I have to wait for the WTS light?

 

[Ididriver]

personly id still wait
just alil bit easier on your starter

 

[Goofyexponent]

WAIT for the WTS light for sure!!

There is the possibility of "short changing" the relay. This means disconnecting it before the controller is ready to. This can damage the contacts inside and cost you a pile of money.

Wait for the light to go out.

 

[gatorman21218]

The glow plugs change resistance as they heat up. They go from low resistance (cold) to high (hot). Using Ohms law, the amperage across the relay goes from high to low as the plugs heat up. When you break the current of the relay when the plugs are still cold, it creates a much bigger arc then when you break the current when the plugs are hot. This arc builds up oxidation on the contacts and will eventually kill the relay.

 

[johneich]

Thanks all, I did not understand it, you made it clear

 

[jim x 3]

The glow plugs change resistance as they heat up. They go from low resistance (cold) to high (hot). Using Ohms law, the amperage across the relay goes from high to low as the plugs heat up. When you break the current of the relay when the plugs are still cold, it creates a much bigger arc then when you break the current when the plugs are hot. This arc builds up oxidation on the contacts and will eventually kill the relay.

This only happens if you switch the ignition to OFF while GPs are glowing. And the GPC relay is (or should have been) designed for that possibility.

In checking the wiring diagram for my '88, the GPC is energized with ignition switch in both RUN and START positions, so you don't "break the current of the relay" unless you switch to OFF. There is no deleterious effect on the GPC's relay in going to START early. This also means that the GPs continue to glow even after starting when the ignition switch returns to RUN. (That's why you continue to see WTS or hear clicking and see the voltage gauge jump even after starting).

When my truck is warm, on a restart for example, I don't always wait for the WTS to extinguish before hitting the starter. My truck starts just fine. So I say go ahead and try it. If the truck starts OK the GPs will heat up faster and there will be less current drain on the battery.

Regards,

 

[94f450sd]

only time i wait for the light is when it was cold.my idi always fired after the first start of the day without waiting

 

[pennsylvaniabo]

only time i wait for the light is when it was cold.my idi always fired after the first start of the day without waiting

They arent saying it wont start without waiting....the question is should you still wait for the light, if it's not cold out etc.

 

[johneich]

They arent saying it wont start without waiting....the question is should you still wait for the light, if it's not cold out etc.

Yes, that is the root of my question, Is it OK to just turn the key straight to start or not?

 

[Goofyexponent]

Personally I wouldn't.

Part of the whole pride about owning a diesel truck is care and maitenence. Who CARES if your buddy can get in, hit the key and peel out in his gas truck while you are waiting for the WTS light to go out. That's part of owning a diesel.

In 10 years, your engine will still be running within spec......and how many gas engine trucks will someone with a gas truck have gone through?

Just be patient unless an axe murderer is trying to hack you up. Then I say giv'r...but I wouldn't start the truck with the WTS light glowing.

 

[94f450sd]

owned my idi for about 8 years.1 set of gp when i bought it.another set after about 4 or 5 years.and 1 controller.

 

[OLDBULL8]

GP's when hot at the end of the cycle are about 680* F, then when the pulseing starts they are about 540* F , starting the engine and combustion occures the prechamber is about 850* to 900*. To prelong the GP life it's best to wait for the WTS lite to go out. Longer life of the relay also.