Been chasing this ghost for some time... Did everything LG said, bought new rear-type O2 sensors and use them in front bungs connected to front wiring harness... Their thinking behind this was that their (LG) headers have such long primaries the exhaust charge is too cool for the front (lower wattage) sensors. Still getting these errors and it is reeking havoc with my LTFT.

I have tried two different set of sensors, Denso and Bosch…


Any input and advice would be appreciated…

 

Ive had the same problems. Ill eventually wrap the headers, but for now, i just shut off the code.

 

That was my next step... pain in the azz but I will do it...

 

Mine throws the P0153 code once every 4-5 days.
I just clear it out and go on with business.

 

It is not just a check engine light. It means you car in not switching rich to lean and back quick enough for the PCM to make accurate LTFT updates. Part throttle fueling precision goes out the door...

 

How do I fix it?

 

Well you might be one of the lucky ones and get away with replacing your O2 sensors with C5 rear-type sensors; they are a higher wattage (hotter). If you are only getting this error every few weeks you will probably be good to go. I am getting the error every time I drive the car, so my last-ditch chance is to wrap the headers...

Good Luck,

 

My O2s were just replaced under warranty and since the car is a C5 I assume they used C5 O2s. Not sure if they used the rear or front sensors but, I assume they used rear type sensors otherwise the wires would not have hooked up correctly. Or maybe I just got a bad one.

Guess I'll have to ask the tech next time I go by there.

 

Will disabling the test make the car have irratic part throttle fueling? You can just delete the code all together can't you. In HP you can set to not show MIL or disable the entire test. Anyone trying disabling the entire test?

John

 

No one is really worried about the "check engine light". The issue is if you are getting the light, your front O2s are not switching correctly and you are NOT getting correct fueling. That is what we are trying to fix for....

FYI: You can turn the MIL light off, but the car is still not switching correctly...

 

Your other option is to do what the viper guys do. They put the 02 in a single primary, and let it speak for the rest.

The other thing is if you tune the car with the o2's off and get your VE table dialed, the LTFT shouldn't matter as much.

At low speed (lots of idling, etc...) you aren't going to keep the temp up. I had also wondered if wrapping or jet hotting them might help keep heat in and the temp up.

 

Ive got jethot headers (jethot ceramic coated, of course) And have always gotten insufficient switching errors and ive gone through more than a dozen o2 sensors. Going to try header wrap shortly.

 

the trick is to get good enough coating to hold in all the heat
I went jet hot 2000 series coating...
everybody I know that has gotten a "standard" coating has ben hit or miss with o2 switching errors...those that have gotten coating made for turbo applications(i.e.2000 series coating)....have not had these issues...and of course everybody I know as had to switch to the bosch #13111 sensor(2002 vette rear o2's)

 

I just bought 100ft of header wrap from Jegs... On FedEx truck now. I am pulling headers now, also, and as soon as the wrap gets here I will do the deal... results soon after...

 

LOL, my wrap is on a truck right now as well. I hope to get it before the weekend to I too can pull headers and see if it helps. Did you buy the silicon spray too? I might just seal up the bottom of the collectors with some high temp paint I have left over (2 cans).

 

I have LGs and they are SNUG where the collector joins the x-pipe. I really think my issues are the 31+ inch primaries and then 4 more inches of collector to the O2 bung... But will see soon...

 

I found a small leak at the collectors and have sealed that up. I'm gonna buy the corvette rears and hope that does it!

John

 

I have the LG's as well but, I just started getting this code in the last 30 days. The headers have been on the car for nearly two years now. So I'm not sure what to think at this point other than maybe one of the new sensors is bad.

 

Obviously check for leaks.

I haven't used wrap on S/S headers, but just keep in mind that it does lead to massive tube erosion on mild steel headers. A set of wrapped headers may only last a year or so in mild steel, sometimes MUCH less depending on use, heat, etc..... S/S may last a bit longer longer, but they will erode, or crack. Under normal use and even more with higher EGTs and header surface temperatures, headers will oxidize and material is actually removed from the headers. This means they get lighter and weaker.

I've gotten some dtaa from JetHoy and Century Performance here...

http://www.centuryperformance.com/heatwraps.asp

Mild Steel (1010) uncoated header exposed to 1200º F. in normal air will have a weight loss percentage of roughly 25% with only 10 hours use at this temperature.

Stainless Steel (410) uncoated header will have roughly 8% weight loss in the same 10 hour period.

A coated mild steel header will have NO weight loss at temperatures up to 1200º F. In fact it will actually gain a bit of weight! Between 1300º F. and 1600º F. the coating will begin to show signs of mud cracking or like the look of lacquer checking. However, limited diffusion takes place between the coating and the substrate, producing a very thin film of iron aluminide, which continues to inhibit oxidation.


Here are a few temperature readings taken at Daytona Motor Speedway.

Below are the test parameters and results using Jet Hot® coated and uncoated headers:

(10 Laps, same engine and car with identical headers, one standard, one Jet Hot® coated. Engine is ran between 6,900 and 7,500 RPM and temperatures are measured immediately after the last lap with the engine idling at 2,000 RPM with identical sustained EGT's of 850º.)

MEASURED AT:
Jet Hot Coated No Coating DIFFERENCE
1" from engine port (on header) 300º 750º 450º
2" above header 210º 300º 90º
1" above floor pan (in car) 115º 165º 50º

Pretty impressive difference, and any of these coatings do not damage the headers, the coating becomes part of the header. Most of the other coating brands are comparable to these figures.

Header wraps are designed to keep the heat in the header to improve scavenging of the cylinders. Keeping the heat in the header allows the exhaust speed to remain high. (the right idea)

There are no header manufacturers that I know of that will warranty their headers if any header wraps are installed on their products.

In most cases the header wrap damages the headers beyond repair. (I will explain below)

If you run a lean mixture, you "may" see a slim performance gain using header wraps.

A rich mixture may show slim to absolutely NO gain in performance.
If you do not mind replacing your headers and header gaskets regularly, and you like that ugly look of a wrapped header, go ahead and use the heat wrap.

In the past, almost all NASCAR and other racing engine builders used the header wraps for the added power gains. But, after having to replace the headers after each race due to the wrap being about the only thing holding the header together, they do not promote the practice any longer! They now utilize the thermal coatings that are chemically and electrically applied to the headers. Those include Airborn, Jet Hot, HPC, and others.

Imagine having to replace a $1200.00 plus set of headers after each race weekend! Few but the most financially well-off race teams can afford to do this. But, it is also in the downtime for remaking a custom set of headers. Most custom header makers do not have copies readily available.

I believe that the wraps are good to protect various items from heat, but not to hold the heat in the header. For example: you can use the wrapping for the protection of fuel and oil lines, wiring, etc.

Cool air needs to be around the header, and insulating it with a wrap to hold exhaust heat in makes the header material temperatures near molten. When you wrap the header you trap the heat in the header, but also in the material that needs to breathe to dissipate heat for it's own survival.

Engineers, Metallurgists, and other experts out there will state that there is no way that the material can fail because it can withstand, and it was designed to withstand, the internal temperatures of exhaust gases. TRUE! But, when the header is not allowed to cool so as to dissipate those extreme temperatures that the wrap is controlling, you have now developed a heat absorption that compares to thermal friction which will will continue to gain in temperature beyond the normal exhaust gas temperatures (EGT's). This is the same as with most any insulation.

Try this experiment ... launder a load of bath towels and then dry them. Immediately pull them out of the dryer and just toss them in a snug pile on your bed. Now leave them there for a day and then open them. You will find that there is still a considerable amount of heat left in the center towels. This heat, even though the outer towels and bed are normal room temperature have been able to contain their heat. This is a simple thermal insulation test, but with your headers you have an internal heat supply coming from the engine. The heat on the outside portion of the header material is trapped between the warp and the header and will continue to fatigue the header. This build of heat is amplified by the wrap. Towels do not need to breathe, header material does.

The EGTs stay the same but the properties of the header material changes in a way of amplifying the temperatures because of the insulation. This action goes against normal laws of thermal dynamics, but this effect is fact, and you have to pull the ears off most engineers before they believe you. This is the trouble with plenty of education, but NO "common sense"!


Anyhow, you can wrap your headers. I'd suggest wrapping them downstream where they start to cool if you decide to do so. I'd let the car run, and check the header tubes with a thermal gun to see where I needed wrap.

I am a BIG believer in coatings myself. I have a turbo Buick that we've used a ton of PolyDyn coating in. I've never used header wrap on any of my vehicles, because I know lots of folks who have, and haven't liked the results. So, I wanted folks to understand the ramifications of using a wrap.

 

What if ive already got coated headers and theyres still too cold.