how do i jump the plugs to check engine light codes

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jjc3209

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i have a 1995 ford bronco. the engine light comes on after it warms up.i need to find out how to check the codes by jumping the connectors if any one can help.thank you. pics or drawings help too. thanks

 

miesk5

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yo,

That's good, but for some reason Ryan didn't show the KOER portion. I aske dhim to put a link in their for his KOER page but he's prob too busy.

So, here it is;

Self Test - & KOER Self-Test, How To Run a; "...The engine temperature must be greater than 50°F (10°C) to pass the KOEO Self-Test and greater than 180°F (82°C) to pass the KOER Self-Test. Make sure A/C is off and transmission is in Park (automatic) or Neutral (manual), release clutch..." MIESK5 NOTE; Self-Test Output (STO) is the Pin in the Lt gray Connector and Signal Return Ground (SIGRET) is Pin E in black Connector Source: by Ryan M (Fireguy50) at fordfuelinjection.com

Also, our pal BroncoJoe19 (Joe) has one complete write-up here; http://broncozone.com/forums/index.php?showtopic=14269&st=0

run it around to heat the engine up and shift thru all gears incl Reverse.

then; turn off all accesories/lights, etc.

Do KOEO portion first

For Key On Engine Running (KOER) portion, the engine has to be @ normal operating temp.

Post any codes found here or look em up in my broncolinks.com site.

 
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jjc3209

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thank you guys. both links worked.i smogged my truck and the (No) im guessing carbon dio. was too high. so it didnt pass. im thinking the o2 sensor or the egr is bad. I just put a new cat on it. what do you think about that? i bought this bronco i love it but but man alot of blood sweat and tears have gone into this thing....

 

miesk5

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yo,

I just saw your last...

Did you do the Self Tests?

Some guesses;

1) High Carbon Monoxide (CO) readings usually indicate a fuel mixture richer than ideal (rich mixture - air fuel ratio below 14.7). In general CO is an indicator of combustion efficiency. The amount of CO in a vehicle’s exhaust is directly related to its air-fuel ratio. High CO levels result from inadequate O2 supply needed for complete combustion. This is caused by a too rich mixture - too much fuel or not enough air (AFR readings below the optimal 14.7, Lambda below 1.0). Circumstances that can lead to high CO emissions:

* Low idle speed

* Improper float settings in carbureted vehicles

* Dirty or restricted air filters

*Excessively dirty or contaminated oil

*Saturated charcoal canister

*Non-functioning PCV valve system

*Improper operation of the fuel delivery system

*Improperly functioning thermactor system

*Catalytic converter intervention and CO concentrations

High CO readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an CO reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance. Low range CO readings are possible, and not uncommon, from a malfunctioning engine equipped with a properly functioning catalytic converter. In such circumstances, truly elevated pre-catalytic converter CO levels will be masked by the catalytic converter and the potential for an CO problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.

NOTE: Great caution must always be exercised when dealing with CO. Concentrations of less than one percent can be lethal. Testing should always be done in a well ventilated area.

2) Normal CO readings. If the combustion process is succeeding at or near the stoichiometric point (AFR equals 14.7, Lambda equals 1.0), CO levels during an idle test will typically measure less than 2%.

3) Low CO readings. There is, effectively, no reading for CO that can be characterized as too low or "below optimal". CO concentrations will appear "normal" even in a lean burning environment, where AFR is above 14.7 (Lambda is above 1.0).

4) High hydrocarbon (HC) readings usually indicate excessive unburned fuel caused by a lack of ignition or by incomplete combustion. Concentrations are measured in parts per million (PPM). Common causes include a faulty ignition system, vacuum leaks, and fuel mixture problems. Circumstances that can lead to a high HC emissions are:

* Incomplete combustion due to fouled spark plugs.

* Improper timing or dwell

* Damaged ignition wires

* Poor compression

* Vacuum leak

* Ineffective or faulty air management system (ECM control of air/fuel ratios)

* Catalytic converter intervention and HC concentrations

High HC readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an HC reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance. HC readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter. In such circumstances, truly elevated pre-catalytic converter HC levels will be masked by the catalytic converter and the potential for an HC problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.

5) Oxygen (O2) readings. Oxygen, measured as a percentage of the exhaust volume, reflects the amount of gas remaining in the exhaust sample after the combustion process has taken place. Ambient O2 readings should be about 20%, reflecting the natural amount oxygen found in the air. The ideal range for vehicles without a secondary air injection system is less than 1.5%. If there is an air injection system, O2 levels will typically fall n the range of 3% to 4%. Pinching off the air hose of a vehicle equipped with air injection should produce O2 levels similar to those found for vehicles without air injection.

6) High oxygen (O2) readings indicate too lean an air-fuel ratio (AFR higher than 14.7, Lambda greater than 1.0). Circumstances that can lead to high O2 emissions are:

* Lean fuel mixture (AFR above 14.7)

* Vacuum leaks

* Ignition related problems causing misfires.

7) Low O2 indicates a rich fuel mixture (AFR below 14.7, Lambda below 1.0).

8) High carbon dioxide (CO2) readings indicate a nearly ideal air-fuel ratio and efficient combustion

9) Low carbon dioxide (CO2) readings indicate a fuel mixture either too rich or too lean, exhaust system leaks, or sample dilution.

10) Oxides of Nitrogen readings. Oxides of nitrogen (NOx), including nitric oxide (NO) and nitrous oxide (NO2), are formed if the combustion temperatures within the combustion chamber exceed some 2,500 degrees F. This can occur when the engine is under load. When excessive temperature conditions exist, the greatest amount of NOx is typically produced at the stoichiometric point (AFR 14.7 or Lambda of 1.0) as the engine is under a light load. If the combustion process within an engine is burning fuel at or near stoichiometric point, NOx levels on acceleration will typically read significantly higher than those measured at cruise and during deceleration. Typically, the NOx readings at idle will be 0 PPM.

11) High NOx Readings. Circumstances that can lead to abnormally high NOx emissions are:

* Malfunctioning EGR valve

* Lean fuel mixture (AFR above 14.7, Lambda above 1.0)

* Improper spark advance

* Thermostatic air heater stuck in the heated air position

* Missing or damaged cold air duct

* Combustion chamber deposits

* Malfunctioning catalytic converter

* Catalytic converter intervention and NOx concentrations

High NOx readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an NOx reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance. NOx readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter. In such circumstances, truly elevated pre-catalytic converter NOx levels will be masked by the catalytic converter and the potential for an NOx problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings.

12) Low NOx readings. There is, effectively, no reading for NOx that can be characterized as too low or below optimal. NOx is naturally 0 ppm at idle. NOx concentrations may appear normal even in a rich burning environment where the AFR is well below 14.7 (Lambda below 1.0).

TOP

Facts to Remember

The byproducts of combustion are dependent on the air-fuel ratio.

13) O2 combines with HC to form CO2 and H2O.

14) O2 combines with CO to form CO2.

15) CO is an indicator of air-fuel mixture richness.

16) HC is an indicator of fuel mixture leanness (or richness) and misfires.

17) CO and O2 are equal at the stoichiometric air-fuel ratio.

18) O2 and CO2 are indicators of exhaust system integrity, sample hose and probe integrity, or both.

19) CO2 is an indicator of combustion efficiency that peaks at or near the stoichiometric air-fuel ratios, and decreases with lean or rich air-fuel ratio.

20) Air injection systems dilute the exhaust sample with O2.

21) O2 is essential for proper operation of the catalytic converter. Its concentrations are essentially unchanged by the catalytic converter, providing a "window" through the converter to the engine. O2 levels are higher on vehicles with properly operating air injection systems.

22) If CO goes up, O2 goes down (inversely related)

23) If O2 goes up, CO goes down (inversely related)

24) With the air injection system disabled and the CO above 1%, the catalytic converter is oxygen-starved. Without O2, it does not fire, allowing exhaust concentrations to be more like readings taken ahead of the converter.

If readings are within the manufacturer’s or local/state/federal allowable limits, it can generally be assumed that the fuel, ignition, and emission control systems are functioning properly. If they exceed the limits, repairs or adjustments are probably called for.

READ MORE @:Emissions Failures, Diagnosis Tech Tips (high CO, O, CO2, etc.) Source: by interro.com via web.archive.org

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High NOx Causes & Tests Source: by Ed H at allpar.com

High NOx is usually due to a stuck, plugged, or disconnected EGR valve. A stuck/inoperative EGR valve commonly causes knocking because the added exhaust flow the valve puts into the cylinder will cool off combustion, and reduce the chance of knocking. The level of knocking must be too high for the knock sensor to reduce. Typically, a failed EGR valve shows up as surging and/or knocking at part throttle, but the knocking can occur any time. Before you go messing with new and different injectors, replace that EGR valve (or check all of the hoses/connections). With a high NOx reading, an EGR problem is pretty certain. Check all of the vacuum lines that lead to the valve (it might be working fine, but the vacuum to operate it might never get there. A test to see if it works is to idle the car, then suddenly open the throttle to 2000-2500 RPM. You should see the EGR valve stem open up as quickly as the throttle did. If it doesn't move or is sluggish, there's the trouble.

As for being tough to remove, the valves often don't rust in place, because the heat passing through the valve dries everything

..............

NOX Failure Overview, General & Common Causes; "...Under the proper conditions, the PCM (engine computer) will command the EGR valve to open, metering some exhaust gas back into the combustion chamber. This has the effect of lowering the temperature in the chamber which in turn lowers the NOx levels. Determining that we have a good working EGR system is key to solving the problem. There can be several components that make up the EGR system on a given vehicle and if any of these become inoperable it could shut the system down. One of the most common issues to have with this system is carbon build-up, clogging the ports and causing a lack of EGR flow. The easiest and least intrusive way to test for flow is to activate the EGR valve with the engine running at idle. This will create a large vacuum leak and the engine should stall or run very poorly. No change in the running condition indicates a restriction in the system or the valve did not open. If the vehicle is OBD II, it may have a “check engine” light on with the code P0401 – EGR Low Flow. Even though the OBD II system monitors EGR and should set a code alerting the technician to a malfunction, total reliance on the PCM may cause a technician to misdiagnose the problem and replace a good working converter. Here are some other common causes for high NOx emissions: • Failed Oxygen Sensor • Leak in exhaust upstream of Converter • Excessive carbon deposits in combustion chamber • Advanced ignition timing • Blocked coolant passage • Lean Air/Fuel mixture..."

Source: by Gary S at magnaflow.com

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GL!

 

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