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Post by Doc on Aug 31, 2010 11:34:44 GMT -5
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Limão
New Member
Posts: 19
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Post by Limão on Sept 1, 2010 10:11:15 GMT -5
I assume the issue is the corrosion on the rightmost terminal. I'm not sure about what caused it specifically, but cleaning the terminal and applying some dielectric grease should prevent it from happening again. Alternatively, applying some OX-GARD should do the trick too.
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Post by Doc on Sept 1, 2010 20:42:37 GMT -5
Vehicle came in with a bad miss. Customer complained about a burnt wiring smell. Here is the next clue I was given.
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Limão
New Member
Posts: 19
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Post by Limão on Sept 1, 2010 21:40:54 GMT -5
I'm sorry if I sound stupid, but what is a "miss"?
Also, is that a radiator hose? If there's a small leak, it could burn nearby wires (hence the burnt wires smell) and wet the coil terminals (hence the corrosion). If by "miss" you mean a misfire, the corrosion in the coil terminals would hurt spark quality, causing misfires. From the first picture, it looks like it's a DIS ignition, which means the corrosion affects two cylinders, making the misfire problem worse and more noticeable.
So the dielectric grease would prevent fluid from getting to the coil terminals, stopping the corrosion and the misfires, but not the smell. Plugging the leak should do it.
If there's no leak, then I'd try and find out what wire is burning.
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Post by Doc on Sept 2, 2010 4:02:58 GMT -5
You are very close to the answer. Limão. My big, fat hand is hiding it, but the coil pack is under it. That is a lower radiator hose and I thought it might be a coolant leak at first, but that was not what it was. I sometimes talk old school and a "miss" is the same as a missfire. You are correct about the DIS, it is a waste spark system. So this engine was only firing on 4 of 6 cylinders.
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Limão
New Member
Posts: 19
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Post by Limão on Sept 2, 2010 11:12:24 GMT -5
So it boils down to the burn smell and the corrosion.
Doc, what are you pointing at in the photo? Is something up with the radiator hose, or you're pointing at something else entirely?
Also, what wire was burnt, then? Maybe the corrosion had something to do with the device the wire was connected to. Was the wire burnt because of short-circuiting or heating?
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Post by Doc on Sept 2, 2010 11:31:49 GMT -5
Now you are following the reasoning I used. The substance on th hose was green and sticky. If no one else does anything on this, I'll post the rest of it tonight. You are using good reasoning.
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Limão
New Member
Posts: 19
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Post by Limão on Sept 2, 2010 13:19:20 GMT -5
When you said before that there were no leaks, did you mean only on the hose, or everywhere? Because green, sticky stuff usually is coolant fluid..
So, assuming no leaks anywhere, unless your customer had had the cooland fluid changed recently and whoever did it accidentally spilled some on that hose, it's not coolant fluid and I have no idea what it is.
Otherwise, assuming no leaks only on the hose, it's almost solved: the hot coolant could've burned the wires and corroded the coil pack terminal. All there's left to find out is where that coolant is coming from. It's a long shot, but maybe a blown head gasket? It would explain the presence of coolant fluid and it's stickiness.
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Post by Doc on Sept 2, 2010 16:25:28 GMT -5
Ok. here it is start to stop. BTW, it was in the solved GM section all this time! Customer complained of a miss, and sometimes stall. Also complained of burnt wiring smell. Noticed it was missing out fairly bad. Quick check found that the two topmost coil towers were not firing. The way I checked them was to remove each plug at the coil and then set them down on top but not snapped into place. I then started the engine and with a pair of insulated plyers removed each wire and checked for spark. This system is called a "waste-spark system" It fires both sides of the coil at the same time. 1+2, 3+4, 5+6. If the coil malfunctions it will not fire on either of the pair. That way I knew I had a bad coil/and or ignition module. This is what I found when I took it off the car. I found a tattletail goo on the lower radiator hose below the module. I also noticed the spark plug wire terminal was rusty (sure sign of a missfire) When I removed the plug-in I found a bunch of insulation goo had run out from overheating. This type of coil pack was one piece. As you can see part of the module melted down, probably from a short. Here is what the new one looked like. When installing the new module make sure that you coat the bottom and the base with di-electric grease. This will insulate and transfer heat. Ran well with no misses after I got finished.
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Post by Doc on Sept 2, 2010 16:29:30 GMT -5
Alright all you guests, get your selves in here and join. Lots more stuff like that in the members only area!
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Limão
New Member
Posts: 19
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Post by Limão on Sept 2, 2010 16:48:30 GMT -5
What was that green goo, then? Insulation material?
Also, did you find out what caused the corrosion?
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Post by Doc on Sept 2, 2010 18:05:19 GMT -5
overheated, remember the electrical smell complaint? Yeah, that was insulation glue that melted out the end and dripped onto the radiator hose.
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