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Re: How do you remove or inspect the maf sensor and egr...
To check the egr valve take some vacum hose had hook it to the egr valve.By removing the factory hose.next **** on the other end of the hose u should feel a vacum.If not and you can draw air it is no good.Also to check the maf sensor.you will need a ohm meter.a maf sensor messures air temp and turn it into signal for the computer to read.u will need the shop manual for the correct ohms.but just to try a quick test a maf has 3 wires.ok one of them is for the ground the other 2 are postive signal.find the 2 postive signal wires and take a ohm reading at room temp.now put it in the fridge for about 10 minutes and take a nother ohm reading it should be diffrent even if not by a lot. if its the same exact ohm im betting your maf is no good.
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Hi, if your EGR valve is stuck open, it could cause a rough idle. P1400 indicates there is a problem with the EGR flowmeter. This may be the result of a valve that is stuck open or may be the cause or may be unrelated. What I recommend is to first check the vacuum hoses on the sensor/flowmeter and also check the hoses from the EGR solenoid to the EGR valve and from the intake manifold to the solenoid. If those are good, remove the EGR valve and inspect the EGR passages for blockage. Also check the valve for properoperation. The valve should default closed and open when engine vacuum is applied to the vacuum port. If you cannot find anything wrong, with the valve or passages, test the control solenoid that supplies vacuum to the EGR valve. It should click open when you apply 12 volts to it. If all this is good, check the wiring from the flowmeter to the computer for continuity. Please let me know if you have questions, and thanks for using FixYa.
In order I would go for the EGR valve, then the TPS. A malfunctioning EGR will keep the car from starting and make it run very rough if you do get it started. The car will run without the knock sensors so I would wait until it runs better before getting those. There are two knock sensors one for each bank of cylinders on the V6. Autozone should be able to tell you which sensor goes on which side.
P0101 - Mass Air Flow (MAF) Circuit Range/Performance Problem Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds. Other MAF sensor circuit DTC trouble codes are P0100, P0102, P0103, and P0104.
Symptoms: You will likely not notice any serious drivability problems, although there may be symptoms.
Possible Solutions: The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures: * Inspect for the following conditions: An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components: - The secondary ignition wires or coils - Any solenoids - Any relays - Any motors * A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor. * A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system. * The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON. * When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude. * A high resistance on the ground circuit of the MAP sensor can cause this DTC to set. * Any loss of vacuum to the MAP sensor can cause this DTC to set.
If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.
Check this it is here as an aid in resolving your P0101 trouble code (DTC)...
P0401 - Insufficient EGR Flow EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.
Symptoms: You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.
Causes: A code P0401 most likely means one or more of the following has happened: * The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced * There is a blockage in the EGR (tube), most likely carbon buildup * The EGR valve is faulty * The EGR valve may not be opening due to a lack of vaccuum
Possible Solutions: In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit. * Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open * Clean out the EGR valve and/or tubing to remove deposits * Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model) * Replace the DPFE sensor (with a good quality / OEM one) * Replace the EGR valve
p0443 is evaporative emission control system, purge control curcuit malfunction, p0449 is emission control system, vent control curcuit malfunction. p0449 is often a filler cap problem on fuel tank. try tightening cap
Replace the fuel filter and clean the MAF sensor with MAF cleaner. Just fallow the instrction to the MAF cleaner. The other thing to is the 1995 4.3 is know to have the EGR valve getting sluggish due to carbon build up. Remove the EGR valve and use Carb cleaner on it to remove the EGR valve and make sure it moves freely. Good luck and hope this helps.
I had a similar problem on my 95 jimmy. It was something that took a lot of time and money to diagnose, but now 3 years later...no proplems. Emissions requires the truck to have an EGR valve (exhaust gas recycle) and this deposits gunk (carbon residue) on your MAF (mass air flow sensor) If you catch it in time you can use a carbon cleaner from Autozone or checker Lightly on the MassAirFlow sensor. If not in time you may have to have either the MAF or EGR valve replaced and these are expensive. After a long period of time being undetected eventually the EGR valve will start smelling like sulfer, this means its to late to clean and save!