What year, the LT1 has a bad habit of cracking the exhaust manifolds in the corners.
C4 Exhaust Leak
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
C4 Exhaust Leak
Hello everyone,
I've been having this issue with the loud engine vibrating like heart beats when the gear is on neutral or parked. My C4's current average mpg stays around 11. I'm assuming that it's something to do with the exhaust leak. There is a check engine light with code 13, but I already replaced the oxygen sensor and the light is still there. I've heard if there is an exhaust leak there can be problems with the oxygen sensor at the same time.
How can I fix this issue and what would cost me to fix it from the repairers?
Any opinions will be greatly appreciated.
Thank you.
I've been having this issue with the loud engine vibrating like heart beats when the gear is on neutral or parked. My C4's current average mpg stays around 11. I'm assuming that it's something to do with the exhaust leak. There is a check engine light with code 13, but I already replaced the oxygen sensor and the light is still there. I've heard if there is an exhaust leak there can be problems with the oxygen sensor at the same time.
How can I fix this issue and what would cost me to fix it from the repairers?
Any opinions will be greatly appreciated.
Thank you.
Racer
Joined: May 2015
Posts: 265
Likes: 21
From: Grand Rapids MI
Exhaust leak allows unmetered oxygen to tamper with the O2 sensor's readings. If it's bad enough, it will force the ECM to remain in open loop, set the idiot light, and run rich. That's likely where your MPGs went--fix the leak & see where you stand.
If you have a jack & stands you can probably repair it yourself. Find the breach, take pics & head to the parts store. There are several types of bandages & putties available for the purpose; some will be easier to use than others based on where the problem is. Should be back on the road in <30min for <$10, unless the damage/rust is severe, or a gasket has failed.
If you have a jack & stands you can probably repair it yourself. Find the breach, take pics & head to the parts store. There are several types of bandages & putties available for the purpose; some will be easier to use than others based on where the problem is. Should be back on the road in <30min for <$10, unless the damage/rust is severe, or a gasket has failed.
Last edited by 84Z51J; Jun 3, 2016 at 02:53 PM.
Oil Producer
Joined: Apr 2014
Posts: 9,377
Likes: 2,737
what year, what side do you think the exhaust leak is coming from, and where in the exhaust do you think its leaking.
Hello everyone,
I've been having this issue with the loud engine vibrating like heart beats when the gear is on neutral or parked. My C4's current average mpg stays around 11. I'm assuming that it's something to do with the exhaust leak. There is a check engine light with code 13, but I already replaced the oxygen sensor and the light is still there. I've heard if there is an exhaust leak there can be problems with the oxygen sensor at the same time.
How can I fix this issue and what would cost me to fix it from the repairers?
Any opinions will be greatly appreciated.
Thank you.
I've been having this issue with the loud engine vibrating like heart beats when the gear is on neutral or parked. My C4's current average mpg stays around 11. I'm assuming that it's something to do with the exhaust leak. There is a check engine light with code 13, but I already replaced the oxygen sensor and the light is still there. I've heard if there is an exhaust leak there can be problems with the oxygen sensor at the same time.
How can I fix this issue and what would cost me to fix it from the repairers?
Any opinions will be greatly appreciated.
Thank you.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
Exhaust leak allows unmetered oxygen to tamper with the O2 sensor's readings. If it's bad enough, it will force the ECM to remain in open loop, set the idiot light, and run rich. That's likely where your MPGs went--fix the leak & see where you stand.
If you have a jack & stands you can probably repair it yourself. Find the breach, take pics & head to the parts store. There are several types of bandages & putties available for the purpose; some will be easier to use than others based on where the problem is. Should be back on the road in <30min for <$10, unless the damage/rust is severe, or a gasket has failed.
If you have a jack & stands you can probably repair it yourself. Find the breach, take pics & head to the parts store. There are several types of bandages & putties available for the purpose; some will be easier to use than others based on where the problem is. Should be back on the road in <30min for <$10, unless the damage/rust is severe, or a gasket has failed.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
Hello everyone,
I've been having this issue with the loud engine vibrating like heart beats when the gear is on neutral or parked. My C4's current average mpg stays around 11. I'm assuming that it's something to do with the exhaust leak. There is a check engine light with code 13, but I already replaced the oxygen sensor and the light is still there. I've heard if there is an exhaust leak there can be problems with the oxygen sensor at the same time.
How can I fix this issue and what would cost me to fix it from the repairers?
Any opinions will be greatly appreciated.
Thank you.
I've been having this issue with the loud engine vibrating like heart beats when the gear is on neutral or parked. My C4's current average mpg stays around 11. I'm assuming that it's something to do with the exhaust leak. There is a check engine light with code 13, but I already replaced the oxygen sensor and the light is still there. I've heard if there is an exhaust leak there can be problems with the oxygen sensor at the same time.
How can I fix this issue and what would cost me to fix it from the repairers?
Any opinions will be greatly appreciated.
Thank you.
Racer
Joined: May 2015
Posts: 265
Likes: 21
From: Grand Rapids MI
True but unless you have LT headers and the sensor is at the very far end, what is the difference? Past the sensor, you can pump in pure oxygen for all it cares. He has an L98 which has the sensor pretty close to the heads, relatively so unless he has a massive head to exhaust manifold leak, I don't think that is the issue.
Race Director
Joined: Feb 2002
Posts: 11,618
Likes: 1,055
From: Compound in the Grove, Ga.
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St. Jude Donor '16
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
OP. Please fill out your profile better so we know what year your car is and location. At this point, based on your 5 posts, you are an L98 which can be any year from 85 to 91. Your location is also very useful when we look at it since someone might be near you who has the tools or ability to come over and look at it in person.
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Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
He has an L98 according to another post. I still feel it would be best to look at the ECM and see if it is getting any data from the sensor. If not, we might have a bad wire from the sensor to the ECM. At this point we are chasing ghosts
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
Thank you so much.
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
OP. Please fill out your profile better so we know what year your car is and location. At this point, based on your 5 posts, you are an L98 which can be any year from 85 to 91. Your location is also very useful when we look at it since someone might be near you who has the tools or ability to come over and look at it in person.
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
Exhaust moves in pulses, so O2 can make its way inside a rusted/cracked pipe in odd ways, but you're right that location is important & will make the scenario more or less likely. I'd fix the leak wherever it is (generally quick & easy, and the neighbors appreciate it), then chase the trouble code.
I will take picture of the rusty part soon.
Thank you.
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
Thank you
Thread Starter
Cruising
Joined: May 2016
Posts: 14
Likes: 0
From: Auburn Alabama
Exhaust leak allows unmetered oxygen to tamper with the O2 sensor's readings. If it's bad enough, it will force the ECM to remain in open loop, set the idiot light, and run rich. That's likely where your MPGs went--fix the leak & see where you stand.
If you have a jack & stands you can probably repair it yourself. Find the breach, take pics & head to the parts store. There are several types of bandages & putties available for the purpose; some will be easier to use than others based on where the problem is. Should be back on the road in <30min for <$10, unless the damage/rust is severe, or a gasket has failed.
If you have a jack & stands you can probably repair it yourself. Find the breach, take pics & head to the parts store. There are several types of bandages & putties available for the purpose; some will be easier to use than others based on where the problem is. Should be back on the road in <30min for <$10, unless the damage/rust is severe, or a gasket has failed.
Thank you for your help
Oil Producer
Joined: Apr 2014
Posts: 9,377
Likes: 2,737
if you are under the car for any of this please please have multiple jack stands and blocks and redundancies.
i had a hole in the rear y pipe. this is what i did after sanding and grinding the hole back to fresh steel.
coated with jbweld, placed steel washer over hole, coated washer.
let sit for 24hrs. or u risk the exhaust pressure blowing through the jbweld. dont use the quickset.
been fine for a long time.
Last edited by VikingTrad3r; Jun 6, 2016 at 01:09 PM.