41-lean
Thread Starter
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Mountain Pass
Joined: Oct 2016
Posts: 172
Likes: 1
From: georgia
41-lean
Tried searching but the search was too short. I have a koer code 41 with a Couple others that are unrelated. I kinda always knew the system ran lean but never got the koer until now. How can I tack this down. It has new plugs and new wires. Same symptom before I changed the plugs and have a random misfire. Any help?
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
What year & make did the 5.0 come from ?
Did the Computer & Harness follow?
Where is/are your O2 sensor/s located ?
1, 2, 3 or 4 wire O2 sensors?
Sometimes Codes are related, please list all Codes.
Lean fuel/air mix can cause a miss, but a few other things as well.
Have you proven you have no vacuum leaks ?
Check your spark quality.
Does this miss happen when engine is cold or warm ?
Did the Computer & Harness follow?
Where is/are your O2 sensor/s located ?
1, 2, 3 or 4 wire O2 sensors?
Sometimes Codes are related, please list all Codes.
Lean fuel/air mix can cause a miss, but a few other things as well.
Have you proven you have no vacuum leaks ?
Check your spark quality.
Does this miss happen when engine is cold or warm ?
Thread Starter
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Mountain Pass
Joined: Oct 2016
Posts: 172
Likes: 1
From: georgia
It came from a 1990 town car
Computer and harness came with it.
The o2 sensors are located in the bottom neck of the header. I had to wel a bung on that side for the o2 sensor to fit.
They are 3 wire 02 sensors.
Most of the vaccum lines are new, can't hear any hissing, sprayed carb cleaner around the intake gaskets and a few other places with no change in idle. I don't have a vaccum gauge but it might be worth getting one.
All spark plugs look good I just changed them again to be sure.
This miss happens cold and warm but more often when cold. I can also feel it while on the hwy when it shifts to od and the Rpms drop almost f else like a shudder
Other codes I got were 4, 34, 18,75. The egr is disconnected.
Computer and harness came with it.
The o2 sensors are located in the bottom neck of the header. I had to wel a bung on that side for the o2 sensor to fit.
They are 3 wire 02 sensors.
Most of the vaccum lines are new, can't hear any hissing, sprayed carb cleaner around the intake gaskets and a few other places with no change in idle. I don't have a vaccum gauge but it might be worth getting one.
All spark plugs look good I just changed them again to be sure.
This miss happens cold and warm but more often when cold. I can also feel it while on the hwy when it shifts to od and the Rpms drop almost f else like a shudder
Other codes I got were 4, 34, 18,75. The egr is disconnected.
Lead Driver
Joined: May 2011
Posts: 5,797
Likes: 453
Check your fuel pressure under load first.
If you can read spark plugs, go for a good long pull then immediately stop to check them, to potentially isolate a particular cylinder that is lean.
How do you have your egr blocked?
Are you running stock heads/cam?
If you can read spark plugs, go for a good long pull then immediately stop to check them, to potentially isolate a particular cylinder that is lean.
How do you have your egr blocked?
Are you running stock heads/cam?
Thread Starter
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Mountain Pass
Joined: Oct 2016
Posts: 172
Likes: 1
From: georgia
I'll have to go buy a fuel pressure tester. How do you check it under load just press the throttle while hooked up to the fuel rail? When I replaced the last ones they all looked similair all cylinders looked particularly lean. I just have the egr there no vaccum line or wires plugged in.
I am running stock heads and cam
I am running stock heads and cam
Lead Driver
Joined: May 2011
Posts: 5,797
Likes: 453
You don't have the egr valve blocked at the base or between the valve and the intake? Did you spray carb cleaner on the base of the egr if it's not blocked?
Also, I can't believe you aren't throwing an egr code if it's not plugged in and has no vacuum to it.
Revving in park is a way to test a very weak pump, if it can't sustain pressure during a Rev it's obviously bad. However, testing while under a load and driving is the only way to test a weak pump that is still strong enough to maintain pressure at idle/low load.
Also, I can't believe you aren't throwing an egr code if it's not plugged in and has no vacuum to it.
Revving in park is a way to test a very weak pump, if it can't sustain pressure during a Rev it's obviously bad. However, testing while under a load and driving is the only way to test a weak pump that is still strong enough to maintain pressure at idle/low load.
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
[QUOTE=Zacbkennedy;Other codes I got were 4, 34, 18,75. The egr is disconnected.[/QUOTE]
We like to see codes in order of test. Thanks.
KOEO - (O) Self-Test Codes
KOEO - (C) Continuous Codes
KOER - (R) Self-Test Codes
"4" - Maybe if you had a 4 cylinder.
"34" - Expected EVP sensor code w/EGR modifications.
"18" - We'll get back to this.
"75" - Possibly a connection no longer connected.
We like to see codes in order of test. Thanks.
KOEO - (O) Self-Test Codes
KOEO - (C) Continuous Codes
KOER - (R) Self-Test Codes
"4" - Maybe if you had a 4 cylinder.
"34" - Expected EVP sensor code w/EGR modifications.
"18" - We'll get back to this.
"75" - Possibly a connection no longer connected.
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Lead Driver
Joined: May 2011
Posts: 5,797
Likes: 453
Ahh. I ignored the additional codes in his last post.
You should remedy the egr code, while it is unlikely that it is the sole cause of your lean condition, it has been known to cause running issues. You need vacuum from manifold to a vacuum reservoir, then from reservoir to egr solenoid, then from solenoid to egr valve. Then just plug the evp in.
You should remedy the egr code, while it is unlikely that it is the sole cause of your lean condition, it has been known to cause running issues. You need vacuum from manifold to a vacuum reservoir, then from reservoir to egr solenoid, then from solenoid to egr valve. Then just plug the evp in.
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Thread Starter
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Mountain Pass
Joined: Oct 2016
Posts: 172
Likes: 1
From: georgia
I don't the egr is attached to the intake just with no vaccum line and the electrical wires unplugged. Do you recommend putting a block off plate instead? I'm about to swap o2 sensors over and reset codes and perform the test again I'll let you know the findings
Lead Driver
Joined: May 2011
Posts: 5,797
Likes: 453
Don't swap o2 sensors (or anything for that matter) until you test the basics....the basics being vacuum leaks and fuel pressure. The o2 sensor is not your issue anyway, unless your harness has a different number of wires than your sensor.
anyway...you should spray something flammable at the base of the egr valve (where the exhaust tube meets the valve) before you do anything else. If the egr valve is not sealing 100%, which is highly likely, then it's a vacuum leak. Spraying a combustible at the base of the egr, and around the egr to intake flange, will determine if it's the cause of a vac leak. If it is a vac leak, we will go about blocking it off.
anyway...you should spray something flammable at the base of the egr valve (where the exhaust tube meets the valve) before you do anything else. If the egr valve is not sealing 100%, which is highly likely, then it's a vacuum leak. Spraying a combustible at the base of the egr, and around the egr to intake flange, will determine if it's the cause of a vac leak. If it is a vac leak, we will go about blocking it off.
Thread Starter
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Mountain Pass
Joined: Oct 2016
Posts: 172
Likes: 1
From: georgia
I took your advice and did not swap the o2 sensor. I cleared codes and started the motor up. Sprayed brake cleaner around the egr valve and intake. No change in engine rpm. Gonna wait till work tomorrow and borrow a fuel pressure gauge and a vaccum gauge and I'll test again at lunch.
Thread Starter
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Mountain Pass
Joined: Oct 2016
Posts: 172
Likes: 1
From: georgia
ill do that when i get home from work. the guys at my shop let me use the smoke tester at lunch. leaking out back of egr valve and pcv valve so ill make a block off plate for the egr and ill replace the grommet and pcv valve and hopefully that fixes the situation.