Duramax remote starter trouble (glow plugs)

[Russell]

Just installed a starter in my DD, the starter starts the truck just fine, but I am having trouble with the glow plug delay system.

I wired up the starter so the glow plug detection wire is connected to the negative side of the glow plug light (the light is at 12V at all times, until grounded which turns the light on) with a low signal detection strategy programmed into the starter.

The problem is that my glow plug light remains on dimly at all times now. The starter ignores the plugs, and simply starts the truck immediately. The glow plugs do work properly, and the light comes on full intensity while they are on.

If I un-plug the starter's glow plug wire and check the resistance across it, my meter reads infinity, and it operates correctly if I manually apply ground to the signal wire just after starting the truck with the remote while sitting inside. It waits until I remove the ground wire, and starts immediately afterwards. The light works properly on the dash as long as the wire is not plugged into the starter.

The truck is also setting a code for a glow plug indicator failure, so the BCM is unhappy with the light staying on dimly at all times.

Any ideas of what might be up? Or would I best best off to find a glow plug inside the engine compartment and tie the starter into that instead, and have it look for a high signal?

 

[Fordum]

Your problem is that the glow plug detection wire on your remote starter system is drawing too much current causing the glow plug light to see a partial ground.
I can think of several ways to fix it, but probably the easiest way would be to wire up a small low current relay in parallel with the glow plug light. In other words, the coil would go from one side of the bulb to the other.
Then, let the contacts of the relay trigger the glow plug detection wire.

Oh Heck, I just realized what the problem is. Sorry, the speech had me a little numb.
You said it waits until you remove the ground wire and then starts. That means it is looking for a High, not a Low. Ground is low. When you remove it, the wire goes high.
When you hook it to the glow plug light, it goes high, because the 12 volts is feeding through the glow plug light. Since it is looking for a high, it has to supply a slight path to ground to be able to detect it.
I suspect that if you program it the other way, it will work. Otherwise, I would use a small relay.
If none of this makes sense, I am running of almost no sleep. Just post a reply, and I will try to make more sense tomorrow.

J.

 

[Russell]

The starter has three different settings. One is a ground detection (sees ground, delays until the ground is no longer present), One is a positive detection (sees 12V, delays until 12V is no longer present) and one is a start on positive detection (does not start until it sees 12V). I tried all three settings, and all three result in a dimly lit glow plug indicator, and the two positive based settings caused the remote starter to wait the factory preset 20sec before it starts the engine. The ground detection setting has the engine start immediately.

However, I do like your idea of a parallel relay that is switching ground, and I'm going to wire one up tomorrow after school. Should take care of the current leaking through the starter, and provide a true ground signal as compared to a virtual ground as it is connected to right now.

 

[Fordum]

Sounds like something is screwy with the remote starter gadget, one of those settings should have worked.
Anyway, the relay will, just be sure to use a sensitive relay that will not reduce the amount of resistance the BCM sees too much.
I am sure it measures the current coming through the bulb to determine if the bulb is good. Putting the coil in parallel will cause a small increase in the current it sees.
But, a sensitive relay that draws very little current should let it see a level that is well within the expected tolerance.

In other words, don't hang a starter solenoid across there even if you have a spare laying around<G>.

A little reed relay would be fine.
In fact, I'll bet you could find a magnetic reed switch and wind a couple of turns of the glow plug light wire around it, and it might trigger just fine. Depending on how much current the light draws.

J.

 

[dhcomp]

Setup a relay, i agree. Then program the remote start unit to detect how you wired it (pos or neg trigger)

 

[Russell]

Well, I tried something different. I installed a diode on the glow plug detection wire, which shut the light all the way off. I'll see tomorrow morning if the starter waits on the glow plugs or not. I somewhat suspect it will if the module works the way I'm guessing it will.

 

[armandjones82]

Would you ever try to have some good remote starter from other brands such as alert and others that are out there in the market today? I think if you find out one in the market today, then things would have been so much easier in order to find that desired part that you need.