EVR help!
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EVR help!
Hey Guy's. need a little help here.
1991 F150 5.8L. How can I tell if my PCM is putting out a switching signal to the EGR vacuum solenoid. I have 12 volts on the power side (DMM form power side to ground) but only 9.6 from the ground side to battery pos. and the EVR will not pull in with only 9.6 volts. I can use jumper clips and put 12 volts on it and it will pull in. It did work for about a week after I put a EGR sensor on it but then the CEL came on and this is what I discovered. The PCM is about a year old now, I'm thinking it's the problem, but how do I check the signal to ground to be sure. thanks!
1991 F150 5.8L. How can I tell if my PCM is putting out a switching signal to the EGR vacuum solenoid. I have 12 volts on the power side (DMM form power side to ground) but only 9.6 from the ground side to battery pos. and the EVR will not pull in with only 9.6 volts. I can use jumper clips and put 12 volts on it and it will pull in. It did work for about a week after I put a EGR sensor on it but then the CEL came on and this is what I discovered. The PCM is about a year old now, I'm thinking it's the problem, but how do I check the signal to ground to be sure. thanks!
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From: Easton,Ks
Yes if you put 12 volts on the ground side the PCM may be bad now. The PCM grounds the ground side.
The EGR Vacuum Regulator (EVR) controls the opening and closing of the EGR valve. The EVR is an electromagnetic solenoid and should have between 20-70 ohms resistance between the pins. +12volts should be constant on one side from the EEC Relay, the computer controls the ground signal when EGR flow is needed.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
Ford EGR valves will open 50% at 4 inHg of vacuum, and 100% at 8 inHg of vacuum.
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The EGR Vacuum Regulator (EVR) controls the opening and closing of the EGR valve. The EVR is an electromagnetic solenoid and should have between 20-70 ohms resistance between the pins. +12volts should be constant on one side from the EEC Relay, the computer controls the ground signal when EGR flow is needed.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
Ford EGR valves will open 50% at 4 inHg of vacuum, and 100% at 8 inHg of vacuum.
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Hey SubFord, thanks for the reply. All the vacuum likes check out and it was working for about a week after replacing the EGR sensor, I check the EVR with my multi-meter. With key on, hot side of EVR to ground was full battery voltage, ground side of EVR with multi-meter to battery pos was only 9.6 volts. I also unplugged the wires from the EVR and used jumper clips to test it. Ground side to ground and positive to batt pos and it worked every time. It doesn't seem to work with just the 9.6 it getting. So, it seems that I have my 12 volts form batt with switch on. So how can I test to see if the PCM is grounding it properly? Thanks for the reply, I see you help out with a lot of this kind of issue's. Very knowledgeable ! thanks.
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From: Kentucky
What code are you getting? You may be going down the wrong path.
The EVR is energized only when the truck is under cruise/light load conditions. At idle, under load or accelerating the EVR is not commanded on to open the EGR valve. Your 9.6V measurement is the voltage drop across the EVR since there is no ground applied.
The EVR is energized only when the truck is under cruise/light load conditions. At idle, under load or accelerating the EVR is not commanded on to open the EGR valve. Your 9.6V measurement is the voltage drop across the EVR since there is no ground applied.
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From: Easton,Ks
If you were using the NEG battery post then the PCM is dropping the voltage 3.4 volts if the battery voltage was 13 volts with the engine running.
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Ok, now we're getting some where. I'm getting code 332, insufficient EGR flow. After warm up the EVR is not sending flow to EGR at part throttle or light cruise. I have a Vacuum gauge T'ed in the line before EVR and I have vacuum (15-20 in), T'ed in after EVR to EGR only a slight amount, maybe 2 in. The EGR test good. The EVP (new) checks good. The wire harness for the EVP back to PCM checks good. Seems to me only the EVR is not getting signal from the PCM to open. As I mentioned, it all worked for a week after I replaced the EVP. Then CEL. Do I need to monitor the voltage signal from the PCM to the EVR while driving? how? thanks again!
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From: Easton,Ks
The PCM does not out put any voltage to the EVR.
Note that the PCM only opens the EGR valve at mid throttle on a warm engine at highway speed.
What code 332 are you getting? (KOEO, CM or KOER)
Note that the PCM only opens the EGR valve at mid throttle on a warm engine at highway speed.
What code 332 are you getting? (KOEO, CM or KOER)
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From: Easton,Ks
There is not a code 332 for KOEO so has to be a CM code.
Continuous Memory (CM) 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.
Continuous Memory (CM) 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.
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Ok, so it's a new EVR. How do I check the harness and the PCM signal? Can I pin it out with a multi-meter? or observe it while driving with the multi-meter hooked to it? I really think everything else is working correct and its the signal from the PCM. thanks
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From: Easton,Ks
Read the PDF in this link and it may tell you what you want to know:
http://www.tomco-inc.com/Tech_Tips/ttt32.pdf
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http://www.tomco-inc.com/Tech_Tips/ttt32.pdf
/
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Problem solved! Thanks subford for all your help. I went through the entire check list. Everything checked out but the process I found a small crack in the vacuum line going to the EGR. I guess that's why it worked for a week but then quit. So, thanks for your patient's and advice! Marty......
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