Smelled burned smell from under dash

[skokie]

I took the truck to the gas station (maiden voyage since tear down) and rigght before I turned into the gas station I could have sworn I smelled wire insulation burning. I filled up the tank and then drove home (1 mile) and then I could really smell it.

I was 1 min from home and I was driving with one hand on the door handle and the other on the key. When I got home I killed it grabbed my flash light and checked under the dash. No wiring was melted. All of the under dash wiring has been replaced with brand new m&h harnesses. I checked all of the wires and even smelled them all. Nothing. The smell was strongest neat the firewall where there is one hole that I have not gotten a plug for

Im thinking that I did paint my ramhorns but I have not ran the truck for 30-40 mins straight to cure the coating. Could that be what I am smelling.Also I felt the wires for heat and nothing. In short it scared the **** out of me and I will be buying a fire extinguisher here in a hour or so.

[Boog]

Now that's a scary deal there. Yeah, it could be the manifold paint burning on. And since you found no hot wires. Was the smell any stronger when raising the hood? Just for safety sake, why not remove the pos cable on the battery when you quit for the night. Piece of mind. You don't want it lighting off after you've gone to bed.

[Camper Power]

[skokie]

Im about to head out and check every wire that I can see on the truck. I have smelled that burning insulation smell before and you never forget what it smells like and I am 98% sure that is what I smelled. After I check it if I don't find anything then I will unhook the positive cable for the night. I just got back from getting my fire extinguisher and its going in the truck tonight. I was telling my story to the guy at the parts place and he said that a friend of his hit the same thing 3 months ago. He tore everything apart and couldn't find a burnt wire. He called the place he got the wiring from and they told him that new wire can do that the first time or two current runs through it. Not sure what to make of that but he has has no electrical fires and it has not done since the 2 times he smelled it.

[DavesRide]

The smell of letting the "smoke" out of it is unforgettable. That is a short to ground. Not hard to do. A wire with Battery + hooked up to ground. It can come in many forms. That is why God made fusible link.

[skokie]

Checked that and the fusable link is good. Also I am not sure but I think I found my issue.

[skokie]

Now looking at the bottom harness and I see a bit of melting plastic or what I thought was plastic. That is that grease they put on there but it looks like it got hot and melted some of the plastic. I check the wires under the dash and under the hood and could not find any burned wiring. Plus in the cab the strongest smell was in the area of the fuse box which this is directly behind.

[st1x10]

Yea that would probably be it. Doesn't look good.

[skokie]

And what sucks is that that harness is only 9 months old. Time to call m&h on monday. So much for driving it this weekend.

[skokie]

And I cant find the original to compare. Must have tossed it. Whats funny is that I have started the truck and let it run so why didnt it do this until I drove it?

[68 P.O.S.]

I had a similar incident happen 2yrs ago. I was driving to work in the morning and just as I turned into the driveway the cab filled with some pretty thick smoke from under the dash. It looked like I had Cheech & Chong in the truck! So you can imagine how fast I stopped & got out. It turned out the entire column harness melted. So I promptly replaced every piece of wiring in the truck...no problems now.

[skokie]

Probably about as fast as I jumped out No smoke but that smell was there.

[neonlarry]

Besides the fire extinguisher make sure you have a wrench handy that will fit the battery cable clamp.

[stllookn]

OUCH...new harness too! I always put lots of driveway time on my truck before hitting the road...and small trips around the block after fixing or repairing something. A ground, good enough to develop that kind of heat and amp draw should have popped a fuse. Inspect the entire harness under the hood to see if you have two wires that are melted together someplace. The "unintentionally" grounded wire will heat up and melt the insulation before it burns. Inspect them all along the full length and you may find the culprit.

I noticed the paint on the firewall with reference to the location of the engine harness connector...it looks like it is 90 degrees out. It is impossible to connect them that way since they screw together but tell me what is going on there for my "cultural enrichment"...LOL!

[skokie]

I did that. I started it and let it run for probably 2-3 hrs total before I took it out. I will be heading out later and unbolt the harness to see what is going on in there.

[stllookn]

The manuals have a very good, color coded, wiring diagram in them. There is probably one on the board here as well...if not I can scam mine and send it off. Start with the underhood harness and trace them all. It is actually quite helpful if you have not done this before. It will help in the future. I have not seen burned quite that badly before. I was spring cleaning and was going to toss a couple of them so let me know if you need a new firewall connector.

[skokie]

Ok I took the harness off and here are the pics. I see a lot of the grease that they use to prevent the connections from corroding but nothing looks burned from what I can see.

[skokie]

[skokie]

[watahyahknow]

see,s like they use too mush grease the bad connections makes the stuf arc that create heat i would at least make new conectors on the plug and replace the fusebox these plug intoo
for a sec i was thinking that they didt crimped the connectors on the copper but on the isolation they make contact then but not fully wish can allso cause the arching and infamous blue/grey smoke

[stllookn]

I would clean it completely with the spray electrical cleaner (both sides of the connector). Some grease can be an excellent conductor so there might have been some grounding going on there. Are any of the wires coming from behind the fuse panel, in the cab, melted? This would confine the problem to the engine side of the fuse panel.

[skokie]

No melted wires at all. I went through it very slowly one wire at a time and nothing burnt at all. I was talking to a buddy today that said some stuff that made a lot of sense. He said you painted your engine, intake, & coated your exhaust manifolds.

This is the first time you have driven the truck. When you drive it the temp goes higher than when you are just sitting there letting it idle and that paint off of the block, intake, and exhaust manifolds is heating up for the first time. It does make sense to me. I totally forgot the smell I got when I painted the other intake that I had installed on it.

Think I will do this. I will take another look at every wire in the truck and under the hood, and if they all check out I will reinstall the harnesses. After that I will start it up and let it idle until the thermostat opens up then idle it up to 1500-2000 and let it. I bought a fire extinguisher last night and I will have it handy in worst case.

[willis0107]

buy some contact cleaner and get rid of the grease There should only be a light film of a corrosion prohibitor sprayed on these. Just my 2

[Luvlegs]

I just went through all this the past two weeks (including be towed home) - Under dash smoked BAD - about 3' of bare wires! I re-did the entire under dash harness and ALMOST installed it. For the heck of it I pulled the engine side also - GOOD THING - behind the hood hinge area, the harness had become pinched between the inner fender and outter. There was another foot of burnt off insulation there! I'd of smoke the whole thing again. My connectors also looked like that inside - mine was more the black silicone though. I removed each terminal end, replaced all the wire and then brass wheel each contact. Then re-installed them - I can't do the linky thing to show you the tools I made to make it easier - the thread has the word "LEARY" in it. I fired up yesterday and was able to move it! yae for me. It's a hassle to do but worth the time and it beats visiting with the fire department.

[skokie]

Ok here is the update. I reinstalled the pieces as is and started up the truck. The choke had the rpm at 1500 so I let it sit there. Hood was open and I was sitting in the truck. About 10 mins into it I started to smell that smell again so I get under the dash with my light and laser thermometer and start looking for burning wire. Didn't see a bit of smoke or anything coming out but man it was starting to smell.

I take a look under the hood and there is a small cloud of grey smoke comign from each of the exhaust manifolds. It was the coating that I was smelling. Smells like burning wire insulation but it got worse as time went on. I let it run at 1500 for about 15-20 mins. At that point the smoke was gone but the smell was still there. It was worse in the cab with the hood closed.

Thanks to everyone for all of the hints. Its greatly appreciated.