I get a P0153 code and #5 & #7 plug wires burning quite often. This tells me that the sensor is not getting hot enough because it happens when I am cruising at low speeds. The heat is going somewhere and it is burning the plug wires. I tried using some sort of asbestos cloth wrap designed for spark plugs. Well, all it does is delay the inevitable burning of the wires. What is the solution?

I am trying Thermotec header wraps with a lot of frustration. The instructions are pure lies. You measure the length of the header and for every bend, add 8 inches. Well, my headers have 3 bends so that is 24 inches. I did that and it was short. OK, next tube I will add 32 inches instead of 24. Guess what? Short again. WTF???

I need to reduce the underhood temps to stop the burn. However, the headers are so close to the frame that at certain RPMs it wil knock as can be seen by the shiny metal frame where it contacts the header.

Can I use a ceremic coating that is commercially applied? Would that be as effective as the wrap? TIA

 

Ceramic coating won't help and with the troubles you state about the wrap, you probably forget it, too. You need to keep those wires OFF of the headers. Tie wraps, brackets, wire separators, etc. - use whatever possible.

For the P0153, check to make sure there are no leaks, the sensor is plugged in completely (this is the front passenger), no frayed or melted wires going to the sensor.

It's too bad the actual headers are rubbing the frame - not much in the way of adjusting that other than 'clearancing' them (read: denting with a hammer). I had a vibration, but it was on the transmission crossmember. I was able to readjust the y-pipe by loosening everything up. I also ground down the end of the tran frame mount just for a little more clearance - not much just about 1/8" or so.

 

I had a prob with #7 as well...bot new MSD 8.5 wires and had them custom make the #7 (u can buy a kit and do it urself). Used tie wraps to make sure and did "slight bending" of the connectors to guarantee clearance. Dbl check with Dynatech about the rubbing...they shud be able to help provided u bot the right ones. What type of truck? R/

 

What aklim said about the wires. Do a search on here, I think there are a few poeple who made brackets. Except I'll add, I have 4wd and my front joint actually hit the header and put a pretty big gouge in it. They replaced it and then I took a 2X4(wood is softer than metal) as a pry bar and pried the headers away from the frame some. It's still cooter hair close, but hardly any rubbing. At least nothing to worry about.

The P0153...I wouldn't suspect you'd get that one. Definitely would expect the P0154 or even the P0155(passenger side stuff, bank 2 I beleive). I'd say if in the end you are wanting to replace those O2's, get the 'vette rear O2's they are a little hotter and MIGHT make the problem go away.

 

That's just it. The wires are stock wires that are tied with wire ties away from the headers and I even bought some "sock" like stuff for wires which are some sort of fibreglass shields and it prolonged the wires but because of the radiant heat, it burnt the wire. I am experimenting with the Accel 9000 wires because those were the only ones. However, I have replaced the boots and plugs with Accel's Flexible boots. I bent them at an almost 90 degree and shortened the wire so I don't have to tie them off. Those and the stock wires have burnt because of radiant heat and even in spite of the boots. They never have come into contact with the header itself.

 

P0157 passenger side

 

My wires are within .5" and haven't had any probs with burning thru. Are u throwing a code? R/

 

yeh but that is "low circuit voltage"...that would be a problem instead of not enough heat....and I beleive it is the rear o2 as well.

 

You got a picture of one of these burnt wires?

 

Fraid not. I tossed them. It was a spot on the wire that looked like it had sat on the header but it was nowheres near the header