check engine light

hey everyone hope you are all doing well. been having a problem with check eng. light. when I start the truck up..the light doesn't go on till about  a quarter of  a mile after I start driving  my 1995 full size bronco 5.8 engine. and it wont go off. I put the scanner on  and codes 332  and 334 are coming up. im not sure if I need the sensor or the egr valve.  with the key on eng off 332 and 334  came up . and with the engine running only 332 came on .I would just replace both if these parts weren't so costly but now im trying to narrow it down.............thanks mike  have a great day

yo,

332 KOER EGR valve opening not detected

DTC 332 "...Insufficient EGR flow detected. Atop the EGR valve there is a sensor called the EVP (EGR Valve Position) sensor. It detects movement of the pintle inside the EGR valve. You can apply vacuum to the vacuum barb on the EGR valve and observe through the holes in the casting whether the valve is moving or not. It may just be dirty which requires some careful scrubbing and NO SOLVENTS. Otherwise, if the EGR valve is functioning and moving when vacuum is applied, the EVP sensor is suspect and the electrical connections to it should be checked first. (Computer needs to know the EGR valve position for emissions control)..."

Source: by greystreak92 (Joe B)

DTC 332 & Possible Causes; "...EGR valve sticking closed EGR valve diaphragm leaks EVR solenoid sticking closed Loss of vacuum to or from EVR Open in EVR VPWR or driver circuits Leak or restriction vacuum hoses.."

Source: by latechsho

DTC 332; "...Continuous Memory DTC 332 indicates the EGR valve did not open with the engine stabilized and the EVR solenoid duty cycle present sometime during vehicle operation. Possible causes: "...Obstructed or cracked hose to EGR valve, Icing, Damaged EGR valve, Damaged EVR solenoid harness..."

Source: by Ford via SigEpBlue

DTC 334 EGR (EVP) EVP circuit above the closed limit of 0.67 volts; "...Failed sensor, & as by rla2005 (Randy) wrote; carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the ****** side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary. The EGR Valve Position (EVP) Sensor used exclusively by Ford, can be the cause of driveability problems without ever setting any trouble codes. The relationship between the EVP sensor and the EGR valve is important to understand. Either one being out of spec can cause similar symptoms. Understanding this relationship will help you to diagnose uncoded driveability problems like stumbles, hesitations, rough idles and stalling..."

Source: by rla2005 (Randy) & miesk5

Testing & Operation; "...The EGR Valve Position (EVP) sensor monitors the position of the EGR valve pintle. The EVP sensor converts the mechanical movement of the pintle into an electrical voltage signal which is relayed to the PCM. The EVP sensor is a linear potentiometer in which resistance varies with the EGR valve pintle movement.Voltage is fed to the EVP by the signal return circuit. As the EGR is opened the EVP directs more voltage to the EEC and less down the voltage reference circuit. The EVP sensor provides the PCM with information on EGR flow and EGR system failures. The EVP should read between 0.24 and 0.67volts at idle with a closed EGR valve..."

By Ryan M.

See next reply for a vg test

Yo,

One more...

EGR Valve Position (EVP) Sensor Testing & Replacement

I was noticing my engine seemed to have less power than usual and it would die once when the idle dropped on cold start-up. I initially guessed that maybe my ECT Sensor was possibly out of range showing warm causing the engine to idle down when not fully warmed up. So I decided to check for Diagnostic Trouble Codes to see what was up.

Using my Equus 3145 Ford OBD-I Code Reader, I received the following DTC Memory Codes:

DTC 327 – EGR valve position circuit below minimum voltage

DTC 334 – EGR closed valve voltage high

possibly a dirty EGR or bad EVP. Interesting, both the EGR and EVP are newer Motorcraft parts.

First, I checked the mechanical operation of the EGR Valve. I placed a ***** driver under the diaphragm on the metal tab attached to the center pintle shaft being careful not to damage the diaphragm. Pushing upward, the valve opened and closed freely.



Then I pulled the bottom vacuum line off of the EGR Vacuum Regulator (EVR). Using my handy dandy hand held vacuum tester, I applied vacuum and noted the EGR Valve freely opening, holding vacuum and then closing when vacuum was released.

http://www.supermotors.net/getfile/966963/fullsize/evp-2.jpg

To be sure, I started up the engine and manually operated the EGR Valve finding the engine idle decreased as it should. Then I used my vacuum tester to operate the EGR and again found a normal decreased idle. Finally I ran a KOER test and visually saw the valve operate. Mmmm… If the EGR Valve was old, sticky or showed signs of excess carbon build-up, I would definitely remove it for cleaning. Yet the mechanical function of the valve is fine, so I ruled that out. I moved on to the EVP Sensor...

So, what the heck is an EVP Sensor anyway? The EVP is a Linear Potentiometer which uses variable resistance to provide the EEC with a voltage signal indicating the position of the EGR Valve Pintle. It is attached to the top of the EGR with three nuts and has a gasket or O-ring which seals the vacuum chamber of the EGR. Under warm, no-load cruise conditions, the EEC commands the EVR to direct vacuum to the EGR causing it to open a calibrated amount which bypasses exhaust gas back into the intake. The EVP then provides feedback to the EEC allowing it to calculate spark timing, air/fuel ratio, EGR flow adjustment and service code notification.

http://www.supermotors.net/getfile/908197/fullsize/egrevp.jpg

http://www.supermotors.net/getfile/966995/fullsize/evp-egr.jpg

With that being said, time to electrically test the EVP with a DVOM. Note that the EVP has a three terminal connector and the specific location of the terminal pins.

http://www.supermotors.net/getfile/966964/fullsize/evp-10a.jpg

The terminal pins are as follows:

• Voltage Reference (5v from the EEC)

• Signal Return (Sensor Ground)

• EVP Signal (Varying voltage to the EEC)

Testing parameters are as follows:

• Reference Voltage (5v at pins VREF and SIG RTN)

• EVP Sensor Resistance (< 5000 ohms at pins VREF and EVP)

• EVP Sensor Resistance (> 100 ohms at pins SIG RTN and EVP)

I started by testing for approximately 5v Voltage Reference at the harness connector. Remember this is a Sensor that operates on 5v EEC Reference Voltage, as opposed to an Actuator which operates on 12v Battery Voltage. Unplug the EVP connector. With ignition Key On/Engine Off, place your DVOM on DC Volts and probe the connector at the VREF and EVP terminals. My 4.78v is good.

http://www.supermotors.net/getfile/966967/fullsize/evp-reference-voltage-5v.jpg

Next I tested for Sensor Resistance at the unplugged EVP Sensor. With your DVOM on Ohms, probe EVP Sensor pins VREF and EVP. You should have less than 5k ohms (5,000 ohms). Note that my test shows 32.6K ohms (32,600 ohms).

http://www.supermotors.net/getfile/966965/fullsize/old-evp-resistance.jpg

Finally I tested for additional Sensor Resistance at the unplugged EVP Sensor. With your DVOM on Ohms, probe EVP Sensor pins SIG RTN and EVP. You should have greater than 100 ohms. Note that my test shows 23.1K ohms (23,100 ohms) which is not even close to 100 ohms.

http://www.supermotors.net/getfile/966966/fullsize/old-evp-resistance2.jpg

So, off to the parts store for a new Motorcraft CX-1464 (F2ZZ-9G428- B) EVP Sensor. You can find one online for about $66.00-$75.00 or the Ford Parts Desk for $98.00. O-Reilly had one for $137.00!!! Just make sure that the gasket is in the box.

Now to test the new sensor before installing. You don’t have to, but it is always a smart move to test new parts whenever you can.

Lets see… Sensor Resistance between pins VREF and EVP is 4.26K ohms (4,260 ohms). Less than 5K ohms (5,000 ohms) is good!

Sensor Resistance between pins SIG RTN and EVP is 126.7 ohms. Greater than 100 ohms is great!!!

Now we remove the bad sensor and install the good one. To remove the unplugged sensor from the EGR, start by removing the three lock nuts. Be careful that you do not drop or misplace them or they will be gone.

http://www.supermotors.net/getfile/966968/fullsize/evp-3.jpg

Carefully pry up and remove the EVP sensor from the EGR.

http://www.supermotors.net/getfile/966969/fullsize/evp-4.jpg

http://www.supermotors.net/getfile/966970/fullsize/evp-5.jpg

Remove the old gasket. If you cannot find one, that may be the source of your problem!

http://www.supermotors.net/getfile/966971/fullsize/evp-6.jpg

Your new EVP Sensor should come with a new gasket. Before installing it, coat both sides with Dielectric Grease to ensure pliability and a tight vacuum seal.

http://www.supermotors.net/getfile/966974/fullsize/evp-7.jpg

http://www.supermotors.net/getfile/966975/fullsize/evp-8.jpg

Clean the top of the EGR and install the new EVP Sensor, once again being careful not to drop the lock nuts.

http://www.supermotors.net/getfile/966976/fullsize/evp-9.jpg

http://www.supermotors.net/getfile/902135/fullsize/egrevp.jpg

After it is installed, use a Q-tip to lightly coat the weatherproof sensor gasket and the barrel of the connector. This will help keep out moisture and make it easy to remove the connector in the future.

http://www.supermotors.net/getfile/966977/fullsize/evp-11.jpg

http://www.supermotors.net/getfile/966978/fullsize/evp-12.jpg

Finally, plug in the harness connector and delete any diagnostic Trouble Codes. I drove around for a while and returned home for a retest.

All seems to be driving good now, no more dying once during the cold start. I know this is a simple service but for some a detailed explanation goes a long way. The hardest part is the simple testing which allows you to confirm the problem and avoid replacing good parts. Good Luck!

by Seattle FSB at http://www.supermotors.net/registry/20487/81147

thank you  for the info  . I will start at the valve itself  then proceed.....my scanner I have doesn't erase codes   so im hoping once I do what needs too be done the c.e.l. will go out.....thanks again always a pleasure reading your topics and helpful posts

Yo Dog,

YW!

btw, I was born at the Naval Hospital in South Philly and lived close by for years. Still miss Geno'so cheese steaks and the Greeks hot dogs.

How to Clear Keep Alive Memory (KAM)

The PCM stores information about vehicle operating conditions and uses this information to compensate for component tolerances. When an emission related component is replaced, Keep Alive Memory (KAM) should be cleared to erase the information stored by the PCM from the original component.

How to Clear Keep Alive Memory (KAM)

The PCM stores information about vehicle operating conditions and uses this information to compensate for component tolerances. When an emission related component is replaced, Keep Alive Memory (KAM) should be cleared to erase the information stored by the PCM from the original component.

To clear KAM: Disconnect the negative side of the battery for a minimum of five minutes.

After KAM has been cleared, the vehicle may exhibit certain driveability concerns. It will be necessary to drive the vehicle 10 miles or more to allow the processor to relearn values for optimum driveability and performance. (Distance is dependent on the vehicle application.)

Let me know how it goes.