Fuel injector harness/spark plug burned.. potential causes?

[GO0BER]

Hey all,

I am in my wifes 2008 Yukon xl 2500 with the 6.0; I was stuck in stop and go traffic and my wife mentioned smelling a weird smell. She then says that she can see a very faint white haze/smoke coming from under the passenger side of the hood. I quickly pull a u-turn into the open lanes of traffic and pull off the road. I had a spark plug wire (right at the coil pack) burn/get hot and then the white clip to the side of it (I believe this is part of the fuel injector harness.. I haven't had a chance to trace it yet) was damaged as well.

The spark plug wire issue caused a few check engine lights to pop on and the dreaded 'shudder' as I dropped to 7 cyl. Luckily we were only 3/4 of a mile from an oreily's that had plug wires.. Got a new wire on and it got me home with no check engine lights and running on all 8. This tells me the wires (more specifically the plug) that are burned may not be bad.. but I don't trust them.. Especially since I do not know what caused the issue in the first place.

Could a bad/failed coil arch and cause the plug wire to catch fire/melt? I assume the white plug is running low voltage/current and it shouldn't get so hot it could start a fire/ burn..

Lastly.. is it possible to get just the 'lower' (the part of the harness facing the ground) from the affected plug/pig tail or do I need to replace the whole thing? I tried doing a few searches for Fuel Injector wire harness and what I was seeing didn't match what I have pictures of. If you could help point me to potential causes and which part(s) to replace I would appreciate it.

I already have new plug wires, if I need a new coil I'll get one, the plug is my biggest 'not sure what to do' issue.

Thanks!

 

[j91z28d1]

I'm glad it didn't catch anything else on fire.

this is pretty amazing and that it ran again after you changed plug wires.

Yep, I got nothing. I believe that white plug is to the coils themselves. take it apart, a few bolts and the whole coil pack comes off the valve cover.


I'm not even going to try and guess what caused that. *edit* and it turned the silicone plug boot white.. I'm pretty sure that takes very high Temps to do

 

[Geotrash]

Wow. You’re lucky that thing didn’t burn to the ground. I can confirm that that’s the harness for the whole bank of coil packs on that side and can easily be replaced as a unit with either a junkyard part or a new one.

Here’s one on evil bay: https://www.ebay.com/itm/3253570534...mFdGJYXQey&var=&widget_ver=artemis&media=COPY

 

[iamdub]

Hey all,

I am in my wifes 2008 Yukon xl 2500 with the 6.0; I was stuck in stop and go traffic and my wife mentioned smelling a weird smell. She then says that she can see a very faint white haze/smoke coming from under the passenger side of the hood. I quickly pull a u-turn into the open lanes of traffic and pull off the road. I had a spark plug wire (right at the coil pack) burn/get hot and then the white clip to the side of it (I believe this is part of the fuel injector harness.. I haven't had a chance to trace it yet) was damaged as well.

The spark plug wire issue caused a few check engine lights to pop on and the dreaded 'shudder' as I dropped to 7 cyl. Luckily we were only 3/4 of a mile from an oreily's that had plug wires.. Got a new wire on and it got me home with no check engine lights and running on all 8. This tells me the wires (more specifically the plug) that are burned may not be bad.. but I don't trust them.. Especially since I do not know what caused the issue in the first place.

Could a bad/failed coil arch and cause the plug wire to catch fire/melt? I assume the white plug is running low voltage/current and it shouldn't get so hot it could start a fire/ burn..

Lastly.. is it possible to get just the 'lower' (the part of the harness facing the ground) from the affected plug/pig tail or do I need to replace the whole thing? I tried doing a few searches for Fuel Injector wire harness and what I was seeing didn't match what I have pictures of. If you could help point me to potential causes and which part(s) to replace I would appreciate it.

I already have new plug wires, if I need a new coil I'll get one, the plug is my biggest 'not sure what to do' issue.

Thanks!

Judging by the white soot, I'm gonna guess you had a high voltage leak and arcing to the low voltage harness nearby. Just my guess. But, apparently, a freak incident nonetheless.

That harness with the large white connector is for the ignition coils, not the fuel injectors. Look at the driver side (both sides are identical/interchangeable) to get a better idea. You can buy just the harness for them ignition coil plugs. Quick search shows it should be under $100. It looks like you can clean up the upper half of that harness connector by picking off the molten plastic of the lower half. Or, and this is what I'd do, is buy a whole rack of coils with the harness in place from a salvage yard or from someone parting out an LS engine. I see this sort of stuff ALL the time on Marketplace. You should be able to get the whole shebang for less than just that harness and you wouldn't have to bother with R/R that harness. The whole rack comes off with just five 10mm bolts and that one harness connector in the center. You'd also have some spare ignition coils. Actually, here's an example on ebay of both racks, coils and harnesses for $100. Or, get both sides with the better factory coils (round) and make lemonade of this by upgrading. Here's some for about $85 on ebay. Those are just quick searches and you could probably find everything for much cheaper. *EDIT* I see Dave @Geotrash found you a quick fix for $35! Also, after studying your pic more, you might already have the round coils. They looked square at first.


What a rack of coils looks like:

These are the upgraded coils:

 

[Dustin Jackson]

I would recommend getting a fire extinguisher moving forward.

 

[GO0BER]

Thanks all for the help. Not sure why I didn't think of coil harness instead of injectors.. It was a frustrating evening to say the least.

Is there any inherent risk with buying used coils? I did a quick search and found summit sells all 8 for about $300.. Without the harness.. I don't mind used parts but after seeing several of you mention how lucky I am this wasn't worse I would happily pay the extra money if there is benefit.

If no benefit I'll be ordering off eBay in the morning.

 

[Doubeleive]

Thanks all for the help. Not sure why I didn't think of coil harness instead of injectors.. It was a frustrating evening to say the least.

Is there any inherent risk with buying used coils? I did a quick search and found summit sells all 8 for about $300.. Without the harness.. I don't mind used parts but after seeing several of you mention how lucky I am this wasn't worse I would happily pay the extra money if there is benefit.

If no benefit I'll be ordering off eBay in the morning.

looks like you had a short to ground and a ground will always take the shortest path which happened to be the valve cover or head.
you should have been smelling something.......
no risk in buying and using used coils or harness but check the ground!, make sure it ohm's to zero

you might want to check those 2 closest coil packs as well look on the backside it's possible one of them developed a crack and everything went haywire.
I bet that was a light show at night under the hood

 

[Geotrash]

Thanks all for the help. Not sure why I didn't think of coil harness instead of injectors.. It was a frustrating evening to say the least.

Is there any inherent risk with buying used coils? I did a quick search and found summit sells all 8 for about $300.. Without the harness.. I don't mind used parts but after seeing several of you mention how lucky I am this wasn't worse I would happily pay the extra money if there is benefit.

If no benefit I'll be ordering off eBay in the morning.

I looked and didn't see the harness on RockAuto and that's the part that's burned so you'll at least need that from evil bay. Might as well replace all of those coils with new, along with new plugs and wires while you're in there.

 

[j91z28d1]

you might check the coil fuse has the correct size in it. I don't know if you're the original owner, but maybe someone stuck a 30amp where a 15 should go, or whatever is supposed to be in there. the lid should say what should be in it

freak accident forsure.. I'd just buy a used bank off ebay, hopefully the upper part of the plug is still in OK shape. maybe replace the spark plug just for the heck of it. I don't think a plug can cause that, but who knows forsure at this point.

 

[donjetman]

I'd be shopping the wreaking yards or ebay for the parts you want.

 

[GO0BER]

you might check the coil fuse has the correct size in it. I don't know if you're the original owner, but maybe someone stuck a 30amp where a 15 should go, or whatever is supposed to be in there. the lid should say what should be in it

freak accident forsure.. I'd just buy a used bank off ebay, hopefully the upper part of the plug is still in OK shape. maybe replace the spark plug just for the heck of it. I don't think a plug can cause that, but who knows forsure at this point.

I am not the OG owner.. in fact since we have owned this vehicle I have done a TON of required repairs and some for peace of mind..

Entire cooling system (now I am thinking of switching to electric fans because this AZ heat is overwhelming the cooling system even with it all brand new), exhaust manifolds, cats, throttle body, spark plugs/wires are all <1 year old. I also did shocks, front and rear wheel bearings, brake rotors and pads, head gaskets..

So the idea of someone putting an incorrect fuse in wouldn't surprise me at this point.. I will have to look

Ordering used set of coils from ebay linked above.. for ~$100 to get all 8 plus the harness/plug.. not too bad.

 

[GO0BER]

looks like you had a short to ground and a ground will always take the shortest path which happened to be the valve cover or head.
you should have been smelling something.......
no risk in buying and using used coils or harness but check the ground!, make sure it ohm's to zero

you might want to check those 2 closest coil packs as well look on the backside it's possible one of them developed a crack and everything went haywire.
I bet that was a light show at night under the hood

My ability to smell is god aweful. I couldn't smell all that well before getting covid and then when I did get it in 2021.. my smell went even more downhill. My wife was able to smell it though.. From the time she mentioned the smell to the time we got off the road/parked was ~2-3 minutes max. I think I also got very lucky that the plug wire burned/melted enough to fall off the coil to prevent additional arching.

I am buying a set of 8 from the above linked EBAY sales, so they will all be getting replaced (at least the passenger side set) but I will check them any way to see if I can get clarification on what actually happened.

 

[j91z28d1]

did the 2500s not have electric cooling fans?

is it's a ecm controlled mechanical fan? not that I know much about it. but I'm a bit surprised that doesn't cool better than the electric fans, unless it's not working right?

 

[strutaeng]

did the 2500s not have electric cooling fans?

is it's a ecm controlled mechanical fan? not that I know much about it. but I'm a bit surprised that doesn't cool better than the electric fans, unless it's not working right?

2500 SUVs and trucks still had mechanical fans. I "think" mechanical fans are still better for heavy towing. Maybe more simple and reliable? Don't know. Just a guess.

OP, I daily drive an 06 like yours. I think it's at idle when they don't cool all too well. On mine running down the street it's fine. Stop and go not the greatest in temperatures around 100F+.

I think an external, auxiliary e fan in front of the ac condenser is probably a better idea for these rigs. I haven't motivated myself to do it, but it should be pretty straight forward. Wire a relay and fuse from the box and put a switch inside the cab for the aux fan. Use a switched 12V source at the fuse box. At least that's what I was thinking.

I'm sure you can also do something more factory with the OEM e fan harness and enable the ECM in HP Tuners on the aux fan so you have 2 fans, the aux and keep you mechanical fan.

 

[j91z28d1]

the obs had an option for a front mount aux fan. I put on one mine to help with the ac. wired the relay to come with the ac compressor. seemed to help high side on the gauge, but didn't notice vent Temps get cooler. the 2 doors just don't have enough ac for south tx in the summer. no real ac

you could use 2 of those. they came with mounts, wouldn't directly bolt on but brackets would be a starting point.

my 2 cents on fans is nothing aftermarket. they are almost all weak.. junkyard for oem fans and find ones that can be used. I put superchargered grand prix fans I my obs, powerful and fit inside the mechanal fan housing. I did it because of the sound, not the cooling thou.

if you go aftermarket, very expensive high end spal or something brushless. even the cheap spal are weak.

2 of these would probably help

15717423 - Genuine Chevrolet Parts

GMPartsGiant.com offers the great deal for genuine Chevrolet parts, 15717423. Fan Assembly, Auxiliary Engine Coolant. All parts are backed by the GM's warranty.

www.gmpartsgiant.com

 

[GO0BER]

2500 SUVs and trucks still had mechanical fans. I "think" mechanical fans are still better for heavy towing. Maybe more simple and reliable? Don't know. Just a guess.

OP, I daily drive an 06 like yours. I think it's at idle when they don't cool all too well. On mine running down the street it's fine. Stop and go not the greatest in temperatures around 100F+.

I think an external, auxiliary e fan in front of the ac condenser is probably a better idea for these rigs. I haven't motivated myself to do it, but it should be pretty straight forward. Wire a relay and fuse from the box and put a switch inside the cab for the aux fan. Use a switched 12V source at the fuse box. At least that's what I was thinking.

I'm sure you can also do something more factory with the OEM e fan harness and enable the ECM in HP Tuners on the aux fan so you have 2 fans, the aux and keep you mechanical fan.

You are correct.. mine does fine while moving, but sitting in traffic its terrible. So bad in fact that at times I feel the need to put in neutral and rev to 1500 to 2000 rpm to get the fan/water moving to cool it back down. This is ONLY while at a stop.. even cruising like 5-8 MPH it does ok.

There is a company that makes a complete factory style install kit. This kit can wire into the factory computer and be programmed to turn them on/off. The complete package of fans + harness is like $800 or so.. Downside is you have to mail them your ECU to flash, or spend more $ to rent/buy the tool/software to do it yourself.

I thought about adding a 'push' fan on a switch, the only downside is this is my wife's vehicle.. She isn't one to want extra buttons to turn on/off while driving and so a manual switch is not ideal. If I can find a way to do it another way.. like overall airflow, speed, coolant temp, throttle position, etc.. I am all for it.. I haven't looked at these other 'trigger' options yet.. Not sure if possible/feasible.. though now that I think about it.. the above linked company's harness on a push fan linked to the 'aux' fan port you were mentioning.. Should be possible... You have given me much to ponder after I get it running again

 

[strutaeng]

You are correct.. mine does fine while moving, but sitting in traffic its terrible. So bad in fact that at times I feel the need to put in neutral and rev to 1500 to 2000 rpm to get the fan/water moving to cool it back down. This is ONLY while at a stop.. even cruising like 5-8 MPH it does ok.

There is a company that makes a complete factory style install kit. This kit can wire into the factory computer and be programmed to turn them on/off. The complete package of fans + harness is like $800 or so.. Downside is you have to mail them your ECU to flash, or spend more $ to rent/buy the tool/software to do it yourself.

I thought about adding a 'push' fan on a switch, the only downside is this is my wife's vehicle.. She isn't one to want extra buttons to turn on/off while driving and so a manual switch is not ideal. If I can find a way to do it another way.. like overall airflow, speed, coolant temp, throttle position, etc.. I am all for it.. I haven't looked at these other 'trigger' options yet.. Not sure if possible/feasible.. though now that I think about it.. the above linked company's harness on a push fan linked to the 'aux' fan port you were mentioning.. Should be possible... You have given me much to ponder after I get it running again

I sometimes rev the engine slightly, around 1,000 RPM while holding the brake pedal with my left foot if at a red light...

I haven't looked at the suburbans that had the 8.1, but I want to say those had a larger radiator, radiator support, and I don't know about the fan. (I think the fan was also larger?)...it seems a little extra CFM is all we need.

I bought an 8.1+Allison from an HD truck and that one had a metal fan, not plastic like the SBC/LS. I haven't looked to see the comparisons.

I've seen on different forums guys that have done e fan swaps from mechanical fan have issues when towing, so I would say if you don't do towing, you'd be okay going only e fan.

 

[mattbta]

the obs had an option for a front mount aux fan. I put on one mine to help with the ac. wired the relay to come with the ac compressor. seemed to help high side on the gauge, but didn't notice vent Temps get cooler. the 2 doors just don't have enough ac for south tx in the summer. no real ac

you could use 2 of those. they came with mounts, wouldn't directly bolt on but brackets would be a starting point.

my 2 cents on fans is nothing aftermarket. they are almost all weak.. junkyard for oem fans and find ones that can be used. I put superchargered grand prix fans I my obs, powerful and fit inside the mechanal fan housing. I did it because of the sound, not the cooling thou.

if you go aftermarket, very expensive high end spal or something brushless. even the cheap spal are weak.

2 of these would probably help

15717423 - Genuine Chevrolet Parts

GMPartsGiant.com offers the great deal for genuine Chevrolet parts, 15717423. Fan Assembly, Auxiliary Engine Coolant. All parts are backed by the GM's warranty.

www.gmpartsgiant.com

There’s a TSB for the NBS trucks that utilize this fan part number you link. Might also work on NNBS.

 

[GO0BER]

I sometimes rev the engine slightly, around 1,000 RPM while holding the brake pedal with my left foot if at a red light...

I haven't looked at the suburbans that had the 8.1, but I want to say those had a larger radiator, radiator support, and I don't know about the fan. (I think the fan was also larger?)...it seems a little extra CFM is all we need.

I bought an 8.1+Allison from an HD truck and that one had a metal fan, not plastic like the SBC/LS. I haven't looked to see the comparisons.

I've seen on different forums guys that have done e fan swaps from mechanical fan have issues when towing, so I would say if you don't do towing, you'd be okay going only e fan.

I'd say unfortunately.. But I'd be lying.. Its not unfortunate lol.. Any who we actually tow quite a bit with it. When we travel as a family (5 of us) we take it and the toy hauler. When its just me or when I want to fully load the toy hauler (which is heavier than the Yukon is rated for) then I take my diesel truck. I also use the Yukon for towing our tractor between locations when moving it. Idk if a bed cap would help on my truck but the Yukon just feels more stable with the tractor behind me.

 

[j91z28d1]

I saw a post years ago where I guy wired a pusher fan into his brake light switch, that way it was mostly only on while not moving but also since you're rolling when you first hit the brakes, in theory it would lessen the amp dump of startup if it's already spinning a bit.

I believe you guys have a pwm fan clutch and that should be adjustable in the tune? can you go in and see if it's adjustments to be more fixed at idle? or is the shrouding just bad.

as for the swap, that would he cool, instead of using their ecm flash, I'm sure anyone can do it. it should just be a drop down box to change a setting in the software to trigger relays instead of pwm for your clutch. maybe a tune from like black bear would kill two birds with one stone. if you can find a online write up you can probably get the fans off ebay and wire the it up yourself for way less and get a tune out of it?