Within the last couple of weeks I've noticed that my car's check engine light flickers on and off while I'm driving. I don't notice it going off unlesss I'm going 50mph or more. Although I'm not sure they are interrelated, when I come to a complete stop at stop lights, my car will come to an idle followed by a noticeable drop in rpms and a rough idle. I hope that makes sense!
I read up on how to check engine codes and these are the codes that I received from the KOEO and KOER tests. I've read the short descriptors for the engine codes, however, I was hoping that someone might be able to give me a little more insight than what the descriptions give me. Any help would be much appreciated!
I'm trying to think of other things that might help anyone that ends up looking at this thread:
1. 96,000 miles on the car.
2. Sometimes there is a fuel smell coming from the exhaust.
Something else that I noticed: along with the fuel smell coming from the exhaust sometimes there is a little bit of white smoke coming from the exhaust - not sure if that would have anything to do with the codes or not...
Within the last couple of weeks I've noticed that my car's check engine light flickers on and off while I'm driving. I don't notice it going off unlesss I'm going 50mph or more. Although I'm not sure they are interrelated, when I come to a complete stop at stop lights, my car will come to an idle followed by a noticeable drop in rpms and a rough idle. I hope that makes sense!
I read up on how to check engine codes and these are the codes that I received from the KOEO and KOER tests. I've read the short descriptors for the engine codes, however, I was hoping that someone might be able to give me a little more insight than what the descriptions give me. Any help would be much appreciated!
KOEO: 67 & 13
KOER: 12, 21, 41, & 91
Make sure the engine is up to operating temp, then run the KOER test again. Code 21 may go away. Temp needs to be 160° or above first.
Code 91 and 41 are 02 sensor lean codes for both banks.
Has any work been done to the car recently?
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89 Coupe
302- Canfield 195's, Comp Cams 1.6rr, Jay Allen Custom Grind, Systemax Intake, 75mm TB, 75mm Pro-M. 24lbs Injectors, Underdrives, Hooker Super Comp headers, 4.10's
Thank you for the feedback! I haven't had a chance to work on figuring this problem out for quite a while so I tried the test again today. I made sure that the engine was up to operating temp (took it for a 10 minute spin - although I did let it sit for about five minutes before I tested it).
Here is what came up:
KOEO - 67 & 31
KOER - 12, 21, 41, 91
Thoughts?
I did have some work done on the car in October - tune up, rack & pinion, valve cover gasket, heater core replaced.
Again, thank you for the help and I am sorry that I did not respond earlier than this...I have been way to busy for my own good!
Looking at the KOEO codes I might have to check this again tomorrow as it looks like I either misread the code the first time I ran the test or I misread it when I ran it today - although I had someone sitting there double-checking the codes as they came up. I used the check engine light method.
If it is indeed a 31 code, would this mean that the EGR has crapped out on me?
Looking at the KOEO codes I might have to check this again tomorrow as it looks like I either misread the code the first time I ran the test or I misread it when I ran it today - although I had someone sitting there double-checking the codes as they came up. I used the check engine light method.
If it is indeed a 31 code, would this mean that the EGR has crapped out on me?
Could be a wiring problem, or the EVP sensor on the back of the EGR valve. Id check wiring first, and go over the 10 pin connectors on the back of the intake. Take them apart and clean them, use some di-electric grease.
Code 41 and 91 are the ones to focus on.
Make sure the orange ground at the back of the passenger side head is connected. If it is, get under the car and check for voltage between the 2 white wires on one of the 02 sensors. Should show 12v. Let me know
__________________
89 Coupe
302- Canfield 195's, Comp Cams 1.6rr, Jay Allen Custom Grind, Systemax Intake, 75mm TB, 75mm Pro-M. 24lbs Injectors, Underdrives, Hooker Super Comp headers, 4.10's
Ford uses two different EVP sensors, a black and a white (or gray). And both will send a different voltage in the same position. At rest, the black sensor will read .75 to .95 volts and the white (or gray) will read .35 to .45 volts. If the voltage reading is correct for the sensor you have and you're wondering if this is the correct sensor for the system, there is an easy way to find out. Remove the EVP sensor and push the pintle in slowly with the sensor connected and the key on, engine off, while watching the voltage on the brown wire with a green tracer (wire colors may vary). You should be able to hold the pintle so the input voltage is .40 volts. Then, redo KOEO self-test. If you still get a code 31, then set the voltage to .80. If you have a pass 11 in KOEO self-test, the system needs a black EVP sensor. The same is true for the opposite ... if .80 gets a code 31 and .40 passes, the system needs a white (or gray) EVP.
Could be a wiring problem, or the EVP sensor on the back of the EGR valve. Id check wiring first, and go over the 10 pin connectors on the back of the intake. Take them apart and clean them, use some di-electric grease.
Code 41 and 91 are the ones to focus on.
Make sure the orange ground at the back of the passenger side head is connected. If it is, get under the car and check for voltage between the 2 white wires on one of the 02 sensors. Should show 12v. Let me know
Bear with me here as I am slowly learning how to do this stuff on my own...particularly anything electrical...
I can do this with any volt meter correct?
I feel dumb asking this but what are the exact steps that I should take to test the voltage between those two white wires? Would I simply connect the negative end of the volt meter to one wire and connect the positive end of the volt meter to the other? OR do I connect the positive (red) end of the volt meter to one of the wires and then connect the negative (black) end of the volt meter to a part of the chassis on the car and test those wires individually? With the key in the KOEO position correct?
Bear with me here as I am slowly learning how to do this stuff on my own...particularly anything electrical...
I can do this with any volt meter correct?
I feel dumb asking this but what are the exact steps that I should take to test the voltage between those two white wires? Would I simply connect the negative end of the volt meter to one wire and connect the positive end of the volt meter to the other? OR do I connect the positive (red) end of the volt meter to one of the wires and then connect the negative (black) end of the volt meter to a part of the chassis on the car and test those wires individually? With the key in the KOEO position correct?
Yes, use a volt meter. KOEO position. Red lead to one white wire, and black lead to the other white wire.
The 02's dont have polarity, so it doenst matter what white wire the leads are hooked to.
__________________
89 Coupe
302- Canfield 195's, Comp Cams 1.6rr, Jay Allen Custom Grind, Systemax Intake, 75mm TB, 75mm Pro-M. 24lbs Injectors, Underdrives, Hooker Super Comp headers, 4.10's
Assistance Understanding KOEO & KOER Codes - 1989 Mustang GT 
