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Header throwing a CEL question.

4K views 31 replies 12 participants last post by  jackalope 
#1 ·
Just got a set of Kooks long tubes and I do plan to have the car tuned however untill I'm able to find a good tuner I wanted to know if the spark plug anti fowler trick would stop a CEL from being thrown? The only cats the car will have will be the 2 little pup cats to help with the raw gas smell (I hope).
 
#2 ·
Come on guys a little help? I talked the wife into how great a deal getting HP tuners is so I'm getting it for Christmas but I'd like to put my headers on before it gets much colder out and I don't want a CEL does anyone know if this will work?

Crap I may just have to do it and see since no one seems to know. :(
 
#5 ·
the rear o2 sensors need to be "turned off" as now they're too far down the exhaust stream to be in the expected range that your factory tune is expecting them to be at. That will come from your custom tune, once you figure all that out.

Do NOT use superchips with headers, can run dangerously lean. If you do set the code running stock tune with headers, once you get your tune then that will take care of itself.

I have been very happy with livernois, and I can reload or switch between tunes anytime I want to. Livernois TCM tune is spot-on, and imho several generations better than the superchips tcm tune from back in the day before I had headers or hfc's.

Good luck jackalope. I bet I know where they came from... :)
 
#6 ·
As far as I know, it won't hurt anything with that sort of CEL. I had to detune for service once and found it wasn't an issue. Didnt' even come on the couple days prior to going in.
 
#7 ·
Do it and see what happens, some cars won't throw the code, some other will, the relation of those who will, by far exceeds those who won't.
Don't give her hell though, drive normal, you can toss her around a little, just don't go crazy with it. Keep an eye on the codes, the light means there is a code, rear cat switching codes are one thing, bank too lean codes doesn't get fixed with anti foulers if you get them, so get her tuned as soon as you can.
 
#9 ·
:angel: :gears:
 
#10 ·
I was throwing code with my extenders and Solo cats. I added some stainless steel pot scrubber to second extender like the others did with the fuel filter.
A chunk of this in the end and I haven't thrown a code in a week. It was almost daily without it. Wife was getting out a new one so I cut some from the old one before I threw it out. No real cost.
 
#11 ·
Ok put the headers on today (took me about 2.5 hours start to finish) and put just under 100 miles on it so far and no CEL yet and I haven't put the anti-fowlers on yet. I have my little Cortex tuner so if any CEL's do pop up I can see what they are. The cat codes I'm not really worried about I'll just keep a sharp eye out for any lean codes! I re-tuned the car to 87 octane but will continue to run 93 octane I figure that way it should keep any spark knock away. As for taking it easy I usually do, cruising in the right lane with the cruise control set at 60 that type of driving. Every once in a while I'll get on it but only for red light to red light type stuff.

Zep I bet you're right! LOL!



Other question for you guys. I can get the car tuned for about $300 but HP tuners is only a little more, should I just get HP tuners and do it myself?
 
#12 ·
Other question for you guys. I can get the car tuned for about $300 but HP tuners is only a little more, should I just get HP tuners and do it myself?
HP Tuners with a tuning license is going to be a good bit more than $300, though still under a grand. You can get it (or EFI Live) and learn it, but it will take a lot more time and effort as well as come with more risk, especially if you've never tuned cars before. On the upside, if you do learn to tune it, you won't need to keep paying to retune the car if you keep modding it. But on the downside again, even if you "learn to tune" with it, how good a job would someone of your experience level (no offense - I am not a tuner either, so this would apply to me as well) be able to tune the car compared to Patrick G?
 
#14 ·
Dude, there is no "downside" to self tuning, Do you think anybody who learned how to tune was born already knowing how to tune ? Lol, be the difference to your "own" car, you're the one driving her, not xxx tuner or tuner shop. Some people prefer to get a custom tune with whatever professional tuner package of your choice whether it is HPT or EFlive, then they customize it little by little, some others would start from scratch, even after having their own cars tuned.

When i started out, i did it with a POS tune from one the big names in tuner shops in the market. After the experience with them and more than a grand "wasted", i was able to tune my car, and by far exceed my custom "Pro" dyno tune, and i didn't even keep any settings from them either, it was basically a new start, my car was cammed at the time, and had full exhaust. I didn't have any previous tuning experience whatsoever, i just read a lot, and had the will to learn and become pro efficient in tuning so nobody was never going to sell me crap ever again.

Granted, you don't pick the skills in 3 nights, there is a learning curve to it, but i don't know anybody who "didn't" learn how to do it, after actually getting themselves into it, we see more engine/trans getting blown up by some of this "Pro" tuners than when the "rookies" do it by themselves. Yes, there are bad tuners, and good tuners out there. some have the good luck to get the good ones, some others doesn't, that's just the way it is sometimes.

How do you know what good is good, sentiment ? dyno bs numbers ? there is a difference between knowing what a good tune is, and another one pretending to know based on opinions, just because the car run, or post good times in the 30-40F weather, doesn't mean it's an "awesome" tune, Do you know of any car that doesn't run faster the colder it gets outside ?

lol how do you know 2 glasses of water in front of you won't taste different if you don't try them out first ? They both look like water from the outside :wink2:

Good luck.
 
#17 ·
This is good motivation to start trying to learn to do my own tuning. If there were easier ways to learn to tune like some tutorials or something I would be more eager to dive in.
 
#15 ·
Depending where you are in MD, you could 5 hours to see Rick Crawford in NC.
 
#16 ·
I agree with Bluegoat. I had my car tuned by an expert using hptuners and then bought hptuners for myself to tweak the tune, make changes, etc. I use it all the time for tweaking the TCM. I am very particular on the tranny tune and have been amazed, in a bad way, by how a couple of nationally known shops tried to tune my tranny.
 
#20 ·
Time to get your wideband AFR gauge installed ... fuel trims only tell half the story.

Wideband O2 tells your AFR ratio at idle, part throttle and WOT, where it's most important to know if you're overfueling or underfueling.

And just to double check, you're JUST using the cortex to datalog your narrowband fuel trims currently, right? Have been tuned back to "factory stock" ECM via the cortex right? (not cortex 87 tune, the actual factory stock one). Don't say I didn't warn ya!

I can't believe I waited so long before getting my wideband setups (I have two of them actually, one per bank) as it truely tells how the engine is doing at a simple glance.

Do you like the change in sound as compared to the manifolds?
 
#22 ·
If I were you I'd take the ECM tune back to 100% factory stock. You very well might be running quite lean (and you have no clue if you are since you don;t have a wideband) ... stock is considered pig rich which should offset the headers and cai improved airflow and be the safest.

Even if you had the cortex 2 year powertrain warrantee, with headers, that's null and void. "for a reason". They don't (currently) support any major exhaust modifications with any of the cortex tunes. I define major exhaust modifications as HFC's and/or Headers. Negligable is catback/muffler/axleback configuration.

Since you got headers, I'd put back to factory stock cortex ECM. You might be able to still keep the TCM from the cortex, that's just the shifting profile and where you feel the most change from the cortex anyways.

Just my recommendation. Long long ago (think drcustomparts days) I did extensive datalogging and found the cortex did not get along with HFC's. Headers are the next step beyond that which is why I recommend against it.

Good luck. Figure out which direction you're going with the custom tune asap so you can start enjoying the newfound power without guilt or scared/hesitation of running lean.
 
#23 ·
Zep, I was gonna PM you but I figure having this in the open forum could help other people so I'm gonna leave it here.

I can data log the fuel trim and 02 readings with the Cortex what should I be looking for? I have no idea what the numbers mean, LOL! I don't doubt you at all I'm just trying to figure this all out.

BTW the headers with the solo axle back's and modded factory enter section sound fan-damn-tastic! I'm LOVING the sound!
 
#24 ·
Your going to be looking for very high positive fuel trims. This would indicate it is running lean and adding more fuel to get the correct AFR. A trim of +10 means it's adding 10% more fuel to reach stoich. However as was already stated the fuel trims only function at part throttle so at WOT you just don't know without a wide band.
 
#25 ·
Oh BTW while I was out I did some data logging for the hell of it and before the headers the best run I ever had was a 12.97 now with the headers and the STOCK tune I did 2 back to back runs the first was 12.88 and the 2nd was a 12.87 both at 111 mph. Now the 12.97 was running the Cortex 91 octane tune with the shift points raised by 200rpm and shift torque at 75%. When I tuned it back to stock with options all it allowed for was shift points to be adjusted no shift torque so I kept the shift points the same but lost the shift torque. I'm SURE that with a "real" tune 12.5's or 12.6's with no problems so long as I an hook up that is.
 
#29 ·
time to move past the cortex. If it was my car, I would not do ANY wot until I got a proper tune on there.

And yes, to add to what Joe said above, if you're datalogging the STFT's and LTFT's you ideally want the 10-point range between -5 and +5 for it to be considered "good".

for example, my livernois tune when cruising at highway speeds is usually at -2 and -1 meaning it's within 2% of stoich and tuned accurately.

If you datalog your STFT's and LTFT's that's only telling part of the story, as when you get on it the system goes into "open loop" which is a calculated mode based on MAF sensor and previously applied fuel trims. If fuel trims are whacky (>10% off in either direction) then serious damage can happen at WOT when the system goes open loop mode. At part throttle, "closed loop" is when the ECM takes data from the stock narrowband O2 sensors and calculates fuel percentage burn by how much oxygen the narrowband o2 sensors detect. At idle and low throttle applications, the LTFT's and STFT's do the hard work, so best to ensure they are between -5 and +5 and that is considered "safe".

At heavy throttle applications, (WOT or aggressive driving) ... the system goes into closed loop mode which is the calculated air and fuel mixture... the only way to know for sure if your engine is running rich (AFR of 10-11-12) or lean (AFR of 14-15++) is to install a wideband O2. It's typical of custom tunes to add fuel when going WOT, so while at idle you might be 14.6 AFR, if you're doing a 0-100 run, if tuned properly, the AFR during the higher revs at full throttle will be in the 11's range, meaning lots of fuel is being added by design.

this is where the cortex might hurt you... if you're running headers and tuned with the cortex at all on your ECM, (without a wideband O2, you wouldn't even know it until you hear the bang and see the CEL illuminate!) if you're running lean at WOT, like 13's 14's etc, then you can damage your engine.

My opinion is to learn about Air Fuel Ratios and do your homework. You'd kick yourself if a hotfoot on a gas pedal caused engine damage because you never realized you were running lean with an unsafe combination of mods.

good luck jackalope, I've said enough on this thread already, maybe I'll let someone else play. ha ha


More info here

Wideband Air/Fuel Ratio Gauge vs. Narrowband Air/Fuel Ratio Gauge

To fully understand why a high performance vehicle tuner would be better off using a wide-band O2 sensor/gauge versus a narrow band setup, we must first understand what each sensor was originally developed to do.

Narrow Band O2 Sensors began to appear on vehicles with the advent of fuel injection in the 1980’s. Their purpose was to monitor component degradation (i.e. fuel injectors, vacuum leaks) of vehicles as they accumulated miles. Their basic job was to let the computer know whether the vehicle was running at an air/fuel ratio of 14.7:1 under idle (ideal ratio for gasoline engines), moderate acceleration, and cruise conditions, and if it wasn’t, to “trim” the injector pulse-width to either slightly lean or richen the engine. When the computer is paying attention to the input from the O2 sensor, the engine is operating in a “closed-loop” capacity. Under heavier acceleration or wide-open throttle the computer ignores the O2 sensor because it requires an air/fuel ratio other than 14.7:1, which is outside the design parameters of the sensor. This is known as “open-loop” operation. The sensor lets the computer know if the engine is running above or below 14.7:1 by sending voltage to the computer in a range between 0 and 1 volt, usually sweeping between the two extremes of this scale. Auto Meter’s traditional narrow-band air/fuel ratio gauges are simply a voltmeter for this signal. This can be seen by the repeated sweeping back and forth of the gauge in most idle, light throttle, and cruise conditions. To summarize, a narrow band O2 sensor is only able to tell a computer (or gauge, for that matter) whether an engine is operating above or below a 14.7:1 air/fuel ratio.

Wide Band O2 Sensors where developed in the early ‘90s as vehicle manufacturers began looking to obtain air/fuel ratio information under all circumstances. This ranged from WOT to varying ratios, for example running air/fuel ratios leaner than 14.7:1 under cruise conditions. Volkswagen and Honda pioneered the development of the wide-band O2 sensors to provide accurate air-fuel ratios under these varying circumstances. They did this by broadening the voltage range in which feedback from the sensor was provided and making a linear scale that provided a fixed voltage that correlated to a specific air/fuel ratio.

High performance vehicle tuners discovered that wide-band O2 sensors are very helpful when accurate air/fuel ratio readings are required to maximize power, reliability, and mileage on modified vehicles. With these benefits in mind and to meet consumer demand, Auto Meter has created a wide-band air/fuel ratio gauge/sensor to augment our popular narrow band, gauge only offering. This unit uses the Bosch LSU 4.2 sensor that is known industry wide to be both accurate and durable, along with an advanced control unit that is encased entirely within the gauge head. Further, the gauge head utilizes both an LED readout, for accuracy, and a radial display for ease of reading. Combined with user definable stoichiometric ranges and voltage outputs, Auto Meter’s wide-band gauge creates a useful and greatly needed tool for the tuning market. As an added bonus, Auto Meter will be offering these gauge kits in our most popular gauge lines.
 
#30 ·
I have the stock tune back on it now, I believe you Zep. Guess I'll leave it with the stock tune and just chill with the gas pedal till I get it tuned, better safe then sorry. I'm hoping to have either HP tuners or to have it tuned as a Christmas present.

BTW I see what you mean Zep as far as the LTFT and STFT comparing the stock tune to the Cortex tune. Stock I'm looking at number in the -9 to even -15 at idle while the Cortex tune I was seeing -3 to +2 so the stock tune deff fattened things up! The stock tune never gets near 0 let alone any + numbers. I know you can't say 100% but this should be better then the Cortex tune right? I REALLY do NOT want to hurt my engine!
 
#31 ·
There have been several people who ran headers with cortex who had resultant engine problems, just trying to protect ya man.

At idle and part throttle you can run rich-sided-fuel-trims no worries, but at the heavier throttle applications (which unfortunately you cannot verify with datalogging with the cortex as above) that's when things tend to lean out and then the stock tune is "better" than the maligned cortex one. Recall that fuel trims are the "correction percentage" of the base tune verses what the O2 sensors and MAF sensor are telling the ECM. That calculation provides how much percentage fuel to cut or add to get everything to burn at stoich.

Best solution is to figure out your custom tune direction and go with it. Then you can REALLY take advantage of those newfound headers and some extra power too.

This thread reads like a book. Sorry for all the long posts but I hypertype most of the time so it really doesn't bother me. But for those reading, alebit longwinded, I hope that the info presented is beneficial.

Having so many hours in R&D and development of SOLO J-pipe catback exhaust systems, beta testing SOLO HFC's, and then headers and wideband O2 stuff, I am glad to share the knowledge when I am able. :D
 
#32 ·
No worries Zep book or not its what I asked for and needed to know so thank you very much! I've got the stock tune loaded now and plan to keep it that way till I get a real tune or HP tuners myself, I'm not killing my engine.

I wonder if I should get something like this.... http://www.summitracing.com/parts/inn-3796/overview/ and then get the HP tuners kit that should work right? Where would I hook up the 02 sensor from this kit to my exhaust, would I need my exhaust shop to add 2 more 02 sensor bungs?
 
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