And what if your running a 94 Explorer thats failed emissions buy scant little - and 2 yrs ago with no Cat passed with flying colors

HC: 2.2000 GPM Actual 1.2693
CO: 60.0000 GPM Actual 10.3724
NOX: 2.8000 GPM Actual 1.1714

As you can see with No CAT it passed way under 2 yrs ago

NOW 1st Test:

HC: 1.7862
CO: 16.7121
NOX: 3.3327

Codes showed the EGR could not be sensed - so I changed the EGR Valve and the other BOX like Sensor

Round 2

HC: 2.0498 - should be under 2.0000
CO: 16.4704 - Passed
NOX: 2.8376 - should be under 2.7000

so after changeing the EGR Control *** and EGR Sensor it has Gotten Worse ......

Sigh

 

cammobus:
After changing EGR valve and sensor, did the codes go away? If not, did you check the third part of the EGR system, namely the EGR vacuum acutator/dump valve(s)? This is an electric control valve, administered by ECM, that ports vacuum to EGR valve to open it, and another electric valve that dumps the egr vacuum port off to atmospheric to close EGR valve. Should be mounted somewhere on firewall with 2 small lines from vacuum source and EGR valve itself. The dump port is open to atmosphere but may have a foam filter (could be fully/partially stopped up), or valve non-functional.

High HC and NOX readings are less likely to be EGR related than mixture/ cat related. EGR main function is above idle RMP's and during deceleration.
Rich mixtures cause high HC readings, and lean mixtures raise exhaust gas temps which elevate NOX readings, which are contradictory in themselves, but O2 sensors that do not switch fast enough could be responsible for both. Of course, the cat itself could also be at fault since it is multi-stage cat designed to break down some of the HC and NOX emissions.
Dialtone

 

Dialtone - Thanks for the Reply - I cannot say about the Codes, but the truck is going back in to get a once over - { I get a Good Deal from a Service Writer and his crew @ a N VA Ford Dealership } - and then i can say more about it - but yes it is kinda contradictory aint it - High HC and NOX - the GF has commented about decreasing fuel economey - I also missed the 3rd aprt of the EGR system - I'll mention it to the Service Writer

 

I broke down and took my truck (96 f150, 4.9) to the dealership to have this code read, and datalogged. Turns out that I have 3 bad O2 sensors, bad cat's and a bad cat monitor sensor. Ford wants $2,582.69 +tax to repair the MIL problem. I don't think so. I will be calling around to see where I can get this (or something better) done for less money. I am considering doing clifford performance header and a full exhaust, but I have to price it out first. Hope you guys have better news on you're P0420 codes than i did.

 

was your engine runnig bad before this code set? misfire, black smoke? if so, then your cats may have been damaged. if i could see the data on a scan tool i could tell you a little more. ford wants to replace everything to fix one or two problems at your expense. you need to find someone with a scan tool that knows what he or she is doing. just because they have a scan tool doesn't mean they know what they are doing. bstavovy@yahoo.com

 

glkearns, Try these sites www.all-catalytic-converters.com , www. oxygensensors.com, www.rockauto.com and www.fordpartscheap.com. The parts are priced much lower than the dealers, S&H charges are free or very low. Ordered some parts from all three sites and received them within two to three days. Rock Auto and Ford Parts Cheap sell original Ford parts. For instance I purchased a set of lower control arms for $176.00 including S&H from them, the local Ford dealers wanted $408.00.

 

No black smoke, no misfiring, avg of 14 mpg moderate loads, lumber rack, so I cant really complain about power or anything like that. Where do I go to find someone knowlegable with a scan tool. Is it worth upgrading my code reader to a scan tool?

 

I am now reading the same P0420 code. It idles a tad rough at times, but is running well otherwise.

Is the general consensus to start with the o2 sensors first and see how she goes? How tough of a replacement is this? Seems like a good idea to hit all 3 of them since I have 113k miles. Any other thoughts? (Sorry for beating a dead horse here!)

 

Ok..... I went to www.fordpartscheap.com per the earlier suggestion to price out some o2 sensors. There is either something wrong with their site .... OR ..... I ain't replacing my o2 sensors!!!!

WTF????

OXYGEN SENSOR, Explorer, Mountaineer, 4.0L, SOHC 97-01 $9,373.00 $7,029.75


Hrm.... seems just a TAD pricy to me????

 

Try this site www.automedicsupply.com

 

Ford has a TSB out for this very problem which is caused by a software problem in the PCM. I know had this same problem with my '96 Should cost $50-$100 to upgrade the calibration to current levels

PCM - MIL ON DTC P0420 Stored in Memory
Article No.
00-26-4




12/25/00




^
MALFUNCTION INDICATOR LAMP (MIL) - MIL
ILLUMINATED - DIAGNOSTIC TROUBLE CODE
(DTC) P0420 STORED IN MEMORY - VEHICLES
EQUIPPED WITH 4.0L OHV ENGINE ONLY




^
LAMP - MALFUNCTION INDICATOR LAMP (MIL)
ILLUMINATED - DIAGNOSTIC TROUBLE CODE
(DTC) P0420 STORED IN MEMORY - VEHICLES
EQUIPPED WITH 4.0L OHV ENGINE ONLY



FORD:
1996 EXPLORER




This article is being republished in its entirety to update the Calibration Information.
ISSUE
Some vehicles may exhibit a Malfunction Indicator Lamp (MIL) Illumination along with a P0420 Diagnostic Trouble Code (OTC) stored in continuous memory with no driveability concerns. This may be caused by the calibration of the Powertrain Control Module (PCM).



ACTION
If no other failures are observed during normal diagnosis, (physically damaged catalyst, stuck fuel injectors, etc.), reprogram the PCM with the latest level calibration in the application chart. PCM reprogramming should be performed before any emission hardware is replaced. If the vehicle already has the latest calibration, follow normal diagnostic procedures for DTC.


NOTE PCM REPROGRAMMING SHOULD BE PERFORMED BEFORE ANY EMISSION HARDWARE IS REPLACED

 

i have this code (p0420) along with p0401 and the p0153...i already replaced the egr sensor and its still throwing codes so my next move is to replace the egr valve. hopefully that will do it. what do you guys think?

 

See my earlier post on p0420 You need your PCM recalibrated before doing anything e

 

Alright guys I really need some help with this before I lose my mind.

2003 F-150 XLT
4.6L 4x4

Superchip
Cold Air Intake
TB Spacer
Flowmaster Muffler

Alright the issue here is a persistent P0420 DTC (catalyst efficiency below threshhold Bank 1)

and here's the story:

All the aftermarket stuff added to this truck was sone over 2 years and 50,000 km's ago. At the same time I had the flowmaster installed I also had the Cat's cut out and straight pipe put in.Bought and installed 2 MIL eliminators for the rear O2 sensors, engine light never came on for over 2 years. A couple mnths ago it came on, some issues with Oxygen and Fuel mixtures were out of range, doing some digging I found a cracked vacuum hose, replaced it, leaky exhaust down pipe, tightened it. That took care of that problem. Then the light came on for my curent problem of P0420, since then I have replaced the fuel filter, all the spark plugs, both O2 sensors on the Bank 1 side, replaced both MIL eliminators for the rear O2's, cleaned the MAF sensor, checked all signal and voltage outputs for all the sensors and they all are within specs, run a bottle of injector cleaner through a tank of gas, rechecked all the vacuum and exhaust lines and probably a few other things I can't remember right now. I've taken it to the local Ford dealer and another local repair shop, both don't know whats causing it, one thing they both told me is that the switching action when at an idle for the low and high fuel/air mixture is slower then normal, sugested mabe the EGR is dirty but it doesn't realy seem like its dirty. I would sincerely love any sugestions or help on this. Possibility the ECU has become touchy or that code is stored in memory and its a glitch?? I disconnected the battery for a half hour the one day and it still came back on.

PLEASE HELP ME BEFORE I JUST RIP THE DASH APART AND PULL THAT BULB OUT!

 

Ok, lets start with the basics and with the performance parts you have installed.

Superchip

I am assuming this is the tuner? A tuner can deliver great gains. If is is some cheap wire in chip, those are a waste of money.

Cold Air Intake

Your truck came with a cold air intake from the factory. While aftermarket cold air intakes can give gains, you first have to sort some facts out. Many intakes do not shield the intake from the hot air under the hood. Hot air is less dense, so the engine will not get as much air as when it is cold. if your intake is not shielded, you are better off putting the stock intake back in.

Air filters that use oil to trap the dirt are known to cause problems. The problems are a result of the oil itself, and the larger openings in the filter media. The larger openings do not trap the particles. Thats why the filter uses, oil, because it is sticky and will help trap more dirt and keep it out of the engine. The oil tends to migrate and fouls the MAF element, which is supposed to give the computer accurate information about airflow. Without good input, the computer cannot make good decisions. The vehicle will tend to run extra rich, and that can damage the converters and O2 sensors over time. Oiled elements are at best like a balancing act. Too little oil, and you get dirt into the engine, and you could end up with damage. Too much, and you get a fouled fuel management, and can still get dirt into the engine.

Two solutions to the filter problem includes 1: go back with the stock paper filter, or 2: use a synthetic dry media. The new synthetics flow very freely, but will not allow any dirt to pass through them. They are washable, and in many cases, cost less than oiled filter. They are also less expensive to maintain because they don't require a cleaning kit.

TB Spacer

This is a worthless mod. It is neither harmful nor helpful.

Flowmaster

Descent enough muffler. Good gains over stock.

Straight pipe Cat Delete

This robs HP and torque from your vehicle and can decrease fuel economy. Allow me to explain. Unburned fuel and unused oxygen are in your exhaust. When these pass through the converter, they heat up and burn. This produces heat, which causes the exhaust to move faster as it goes through the converter. This positive induction helps draw more spent exhaust from the cylinders, and that in turn increases the power of the engine. You should put cats back on to maximize your performance. This would also take care of your P0420 code.

O2 simulators

Apparently they don't work. Simulators don't really work that well, because the vehicle looks for more than just O2 levels and signal frequency, most OBD-II systems also measure response time. When you run a simulator, the response time is infinite. Simulators are supposed to allow you to run without cats, tis a shame that the vehicle would produce more power if it had good cats, and the simulators don't even work anyway. Probably a good part of why they are illegal.

Now for the solutions
Clean your MAF sensor. This helps get better more accurate readings. Use a cleaner made for this purpose, such as CRC MAF cleaner. Replace your O2 sensors with OE or equivalent sensors (Bosch should work well). Replace the cats with a good quality cat, this will help with both the performance, it will resolve the P0420, and will probably help with the EGR code as well.