Hey guys,

So I just moved to Colorado and I have to pass an emissions test to get my license plate. Long story short, when I bought my truck over two years ago, one of the glow plugs was out and come to find out, it mushroomed in the head. I've had an engine code since I bought it and haven't bothered until now. I don't want to pull the head to fix the glow plug and I don't want to break off the tip and try to fish it out....

If this were something really emissions related I wouldn't try to get away with it and actually fix it but since I don't want to rip apart my motor, how do you guys suppose I can get around this engine code problem?

I've been thinking of trying to figure out a way to mount a glow plug externally and plug it in, but just remembered that the harness connects inside the valve cover. I'm guess that I could probably splice a new harness into the existing one then find a pipe to thread the glow plug into to make sure nothing catches fire. Sound feasible?

second idea is to complete the circuit somehow, tricking the computer into thinking a working glow plug is working. Any ideas?

I'd really appreciate some ideas/advice guys. Thanks!

 

Thats alot of heat to hide.

I know the GPCM is cali, like my truck, and the turn off th eengine on coast is cali, wonder if a person could put a non cali PCM in and a regular old GPR that is clueless to one bad GP?

 

The first thought I had was a high watt low ohm resistor, but that would have to be one huge resistor to handle all the power going through it and it probably wouldn't fit under the vc. Here's a bump for the morning guys.

 

Morning fellas... Gonna bump my thread again this morning, I've got a day off work coming up soon and need to try and figure this out. Any thoughts?

 

could you splice into another wire that is connected to a working glowplug? So the bad one has no wire going to it and the glowplug next to it that does work has two wires connected to it???

 

The GPCM is like a giant ammeter. Splicing like that won't work because it reads the amps drawn by the GP's. Thats how it sets the light when one goes down.

 

Can it just be temporarily grounded to the head? I figure that's all the glow plug is anyways, but I don't know if that would cause havoc with the rest of the engine electrical.

 

Maybe. GP's aren't dead shorts though, they have some resistance. It might work.

 

I wold try grounding it to the block and see what happens. I think it might work.

 

I don't think grounding a voltage is a good idea. Maybe you could splice it into the air intake heater. Not really sure.

 

A small 12 volt motor, or 12 volt sol.. I wouldnt use the AIH, or go straight to ground.

Why would it matter though, so long as you running well, you should pass the smog test, do they look for engine codes as well?

 

DO NOT ATTACH IT TO GROUND.

Sure-fire way to let the smoke out of the wire and make sure you have to replace the valve cover harness and the wiring to it.

The glow plugs ARE resistors; very low resistance when cold, but as they heat up the resistance increases to the point that the current drops substantially. Think of them as a very thick light bulb filament. Basically a dead short when cold but as the heat goes up, so does the resistance.

 

Well, I think the Check engine is a ground fault light in that it turns on when a ground is applied. What about finding the wire, measuring the 'all good' signal and emulating it? Of course, you may not want to back feed to the pcm so a diode may be in order. That would be my idea rather than fooling with the harness...

 

I like this Idea, expensive but cheaper than puling the head plus you would get rid of the CALI emission stuff....then again that may be another reason for them to fail ya........

grounding it would scare me, the glowplug is I think is around 1 ohm at max and around 50 watts so you might want to try a resistor like this link to resistor if you can fit it under the valve cover, or get tricky and pull that pin in the harness and route it through the resistor.

it's only a couple a bucks so it would be cheap to try.

 

If the bad glow plug has shorted to ground, I'd just unplug that one glow plug's connector, clear the code and see if it resets. If the glow plug failed 'open', then faking the resistance may work. But, having a glow plug inside the valve cover while the engine is running seems like a bad plan, and having a grounded glow plug dangling outside the valve cover during an e-test seems kinda redneck.

You may just want to have a shop properly replace the fragged glow plug, since you may be needing it in Colorado anyway. If you spend hours just to get around the the test, you'll just spend more hours fixing it later.