EGR Code 84
12-03-2013, 07:23 PM
#1
Thread Starter
Join Date: Dec 2013
Location: PA
Posts: 4
EGR Code 84
Completely stock 1991 LX 5.0 Convertible, 220,000 miles.
The original problem was that it horribly failed NOx emissions in PA last Friday. HC was a tiny bit high.
Car starts and runs great.
No CEL
I checked the codes. No codes in present memory. Code 33 in stored memory.
Over the weekend:
I checked the EGR with a vacuum pump and it works.
I tried to check the EGR solenoid but one vacuum port broke off. I tried to fix it with plastic glue, which kind of worked. EGR still not working.
I took the solenoid apart and found a broken O-ring which I replaced, then cleaned and reassembled the solenoid.
I checked the solenoid with an ohmmeter and it had zero resistance.
I left the battery disconnected while I was reinstalling the EGR solenoid. I hooked everything back up and before I started it I checked the codes.
I gave me code 84 in present memory.
Monday:
I drove the care to work and back (24 miles) and it ran fine. No CEL
I checked the codes when I got home: Codes 84 in present and 33 in memory.
Today:
I installed a new solenoid. I still have code 84. No CEL. Car runs great.
I checked and I have 12+ volts on one side of the solenoid and 0 on the other.
I used a test light as a resisted ground on the computer side of the solenoid plug and I can make the EGR work.
I jumpered the solenoid plug with a test light and then initiated the KOEO test. The light did not flicker as the test activated the solenoids and switches.
I took the plug off of the computer and I checked the wire from the solenoid plug to the computer plug pin number 33. I have 0.2 ohms telling me that the wire is ok.
In summary:
The EGR itself works. I have power to the EGR solenoid. I have a good wire from the solenoid to the computer. I can make the EGR work by using a resisted ground.
Question:
Did I do something to the EGR solenoid when I took it apart that caused a short in the solenoid which damaged the computer? Is that possible? Do I have a bad Computer?
Why is nothing ever easy?
The original problem was that it horribly failed NOx emissions in PA last Friday. HC was a tiny bit high.
Car starts and runs great.
No CEL
I checked the codes. No codes in present memory. Code 33 in stored memory.
Over the weekend:
I checked the EGR with a vacuum pump and it works.
I tried to check the EGR solenoid but one vacuum port broke off. I tried to fix it with plastic glue, which kind of worked. EGR still not working.
I took the solenoid apart and found a broken O-ring which I replaced, then cleaned and reassembled the solenoid.
I checked the solenoid with an ohmmeter and it had zero resistance.
I left the battery disconnected while I was reinstalling the EGR solenoid. I hooked everything back up and before I started it I checked the codes.
I gave me code 84 in present memory.
Monday:
I drove the care to work and back (24 miles) and it ran fine. No CEL
I checked the codes when I got home: Codes 84 in present and 33 in memory.
Today:
I installed a new solenoid. I still have code 84. No CEL. Car runs great.
I checked and I have 12+ volts on one side of the solenoid and 0 on the other.
I used a test light as a resisted ground on the computer side of the solenoid plug and I can make the EGR work.
I jumpered the solenoid plug with a test light and then initiated the KOEO test. The light did not flicker as the test activated the solenoids and switches.
I took the plug off of the computer and I checked the wire from the solenoid plug to the computer plug pin number 33. I have 0.2 ohms telling me that the wire is ok.
In summary:
The EGR itself works. I have power to the EGR solenoid. I have a good wire from the solenoid to the computer. I can make the EGR work by using a resisted ground.
Question:
Did I do something to the EGR solenoid when I took it apart that caused a short in the solenoid which damaged the computer? Is that possible? Do I have a bad Computer?
Why is nothing ever easy?
12-03-2013, 08:10 PM
#2
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
Did you test the evp sensor? EGR valve position sensor. That code 33 just says that the computer didn't see the egr open. It doesn't mean that it isn't . Those evp sensors wear out , especially with that kind of milage on it.
As far as the egr vacuum solenoid I would replace it, Ive never had much luck with them after taking them apart lol.
As far as the egr vacuum solenoid I would replace it, Ive never had much luck with them after taking them apart lol.
Last edited by dawson1112; 12-03-2013 at 08:12 PM.
12-03-2013, 08:23 PM
#3
Thread Starter
Join Date: Dec 2013
Location: PA
Posts: 4
I did not check the EGR position sensor. I replaced it several years ago and I would expect codes 32 or 34 if it were the sensor.
Also, I forgot to mention in my first post that I connected a vacuum gauge in the line from the EGR solenoid to the EGR and brought the gauge into the car where I could see it. I drove the car back and forth to work Monday and today. The vacuum gauge did not register any vacuum at all which told me that the solenoid was not working.
I replaced the solenoid tonight after work and I have not driven it with the vacuum gauge attached. I will try it again tomorrow.
With the new solenoid I can apply a resisted ground (test light) to the computer side of the solenoid plug and I can make the EGR work.
The new solenoid had about 40 ohms resistance. My old solenoid had zero.
I am still puzzled as to why code 84 did not appear until after I disassembled/reassembled the old solenoid.
Also, I forgot to mention in my first post that I connected a vacuum gauge in the line from the EGR solenoid to the EGR and brought the gauge into the car where I could see it. I drove the car back and forth to work Monday and today. The vacuum gauge did not register any vacuum at all which told me that the solenoid was not working.
I replaced the solenoid tonight after work and I have not driven it with the vacuum gauge attached. I will try it again tomorrow.
With the new solenoid I can apply a resisted ground (test light) to the computer side of the solenoid plug and I can make the EGR work.
The new solenoid had about 40 ohms resistance. My old solenoid had zero.
I am still puzzled as to why code 84 did not appear until after I disassembled/reassembled the old solenoid.
12-08-2013, 10:30 AM
#4
Thread Starter
Join Date: Dec 2013
Location: PA
Posts: 4
**Update**
After replacing the EGR solenoid valve I drove the car back and forth to work with the vacuum gauge attached. There was no vacuum to the EGR.
I found a good used breakout box which should be here on Tuesday. I also found an original Ford Shop Manual. I have a few more things to check.
Anyone have any ideas?
After replacing the EGR solenoid valve I drove the car back and forth to work with the vacuum gauge attached. There was no vacuum to the EGR.
I found a good used breakout box which should be here on Tuesday. I also found an original Ford Shop Manual. I have a few more things to check.
Anyone have any ideas?
12-13-2013, 05:20 PM
#5
Thread Starter
Join Date: Dec 2013
Location: PA
Posts: 4
**Update**
I purchased a used Rotunda Breakout Box and a Ford Factory Service Manual. I found a diagnostic on http://www.justanswer.com/ford/24bzg...t-failure.html and followed it.
I was able to trace the code 84 problem to the computer. I found an exact replacement computer on eBay and replaced it today.
Problem solved. No more trouble codes. I drove the car with the vacuum gauge attached and the EGR is working again.
Now all I have to do is get the car re-inspected.
I purchased a used Rotunda Breakout Box and a Ford Factory Service Manual. I found a diagnostic on http://www.justanswer.com/ford/24bzg...t-failure.html and followed it.
I was able to trace the code 84 problem to the computer. I found an exact replacement computer on eBay and replaced it today.
Problem solved. No more trouble codes. I drove the car with the vacuum gauge attached and the EGR is working again.
Now all I have to do is get the car re-inspected.
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