2004 ford f-150 xlt 5.4L 52000 miles Have been receiving error codes p0420 p0430 after a year or 2 of having Dynatech headers, cats, and Banks monster exhaust installed. Truck still runs fine. Have anyone experienced similar problems. Suspected leak, downstream sensors, cats. Checked for leaks, connections for sensors, seem ok. At first I was just getting the p0430 code, after 4 months now Iam getting both. Which do you think is more probable, dynatech cats going bad or both downstream sensors? Please respond one and all with experience in emmissions. If cats, does dynatech make and have available upgrade replacements? Thanks, pwb
pwillybrown@hotmail.com

 

i don't know about your problem, but how big of a difference did your headers make?

 

Well I did some other things to it as well, It improved acceleration and gas mileage 150 mile run at 60-65 mph up to @25.2 mpg. I havent put it on track but it is approaching 400 hp with all improvements, NO supercharger.

 

These codes are typical after a longtube header install. The 02 sensors have been relocated farther downstream. The 02 sensors take samples at timed intervials based on exhaust pulses and thier location. Now thats thrown out the window. They are still taking samples but the timing is off with the exhaust pulse due to the new location. This change is accounted for in custom tuning.

400hp and 25mpg. Please do tell how you acomplished such a feat.

 

Fat chance on the gas mileage unless you installed a 4-banger in there.

 

Do the gotts 02 mod on the rear sensors and clear the codes. P0420 is bank 1 cat below efficiency and p0430 is bank 2. 25mpg if you installed larger tires and didn't fix the speedo being off and taking that reading off the dash computer

 

I'm curious what I will bump to.. Currently 20-21 with my roush wheels on highway

 

I'm curious about the MPG's as well I only get around 17 in my mostly stock 05 4x2 with the 5.4.

 

I was expecting some naysayers on the gas mileage stats and I will say that all the tire/wheel size & pressure, rear ratios, speed limiter, etc. are altered/corrected with the Sniper Tuning software package + driving style has a little to do with that. The witness that rode with me was somewhat surprised also when the calculating was done. However, some people just refuse to believe it can be done. That figure was my all time best in nearly 8 years of owning the truck. Normally I use the accelerator much more aggressively yeilding a lower mpg with a higher fun factor. Personally speaking it's not very much fun to try to get good gas mileage, I think thats why most people don't even try. You can tell that by driving down the Interstate.

 

So how are you getting 400hp?

 

Top to bottom- GMS-Volant c.a.i. hand smoothed like 600 grit inside the tube with access to all the cold air it can get, 85 mm BBK T.B. also inside polish, Twin electric radiator fans -Troyer, WP fan removed. Under drive crank, alternator pulleys, 200 amp alternator for the extra drain with electric water pump and fans. Dynatech long tube internally smoothed stainless headers, h.p. cats, into Banks Monster 3" exhaust to 3.5 tailpipe, all of which have been smoothed internally with appropriate size drill mounted and extended ball grinders from front to back. Remember, if it ain't smooth it will have drag. Last but not least a modified sniper software tune with slight enrichment and a couple of other secret adjustments. (93 octane always) unless you can afford 100+ av gas all the time for THAT tune. Now if you want to go into the engine which most people including me till it needs an overhaul, dont want to do. You probably already know some of those. If the engine you do this to is in sound condition it will closely approach 400 hp NOT using supercharger or nitrous. Yes its time consuming, patience pays off. Cheaper than a supercharger too. Thanks for the info about the sensor placement issue.

 

~post removed by Bubba~

 

I only see roughly 60hp worth of mods there. 5hp from the tb and thats at 5000rpm, efans will get you around 10hp, under drive pulleys 5hp, elec waterpump 5-10hp, headers 20hp, and lets say 20hp from a tune, and that tune would never net you 25mpg. While I can certainly appreciate your efforts in smoothing things out and I assume you bored the tb to 85 since BBK only makes an 80mm I think your 400hp number is a long ways off. A dyno sheet to support your claims would go a long ways. Otherwise anyone you talk to is gonna call you out for BS. Especially the "secrets" in tuning when you didn't even know to change the parameter for long tube headers.

 

Put the truck on a dyno. You will be surprised at the number. You *might* be at 400 crank hp. Definitely not 400 wheel hp.

I have heard of the gotts mod working on the sensors. Give it a try