1987 Corvette L98 turns over fires but won’t start
07-14-2019, 11:24 AM
#22
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[QUOTE=vader86;1599752224]If your O2 sensor is dead or dying it can flood the engine and make it cut off.
Replace the sensor and check its wiring, that should've been the first thing you did.[/
The sensor isn’t failing it’s just not getting the exact reading due to having no cats
Replace the sensor and check its wiring, that should've been the first thing you did.[/
The sensor isn’t failing it’s just not getting the exact reading due to having no cats
07-14-2019, 12:45 PM
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07-14-2019, 03:35 PM
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07-14-2019, 07:33 PM
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I ran without cats for years on an otherwise stock engine and never got an o2 sensor code, unless you moved the bung, that doesnt compute. Your pressure makes no difference, the o2 does not care about back pressure in the system. I still don't have cats and still don't have any O2 codes, 7-8 years and counting.
Fix the trouble code.
Fix the trouble code.
Last edited by vader86; 07-14-2019 at 07:36 PM.
07-14-2019, 08:55 PM
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I ran without cats for years on an otherwise stock engine and never got an o2 sensor code, unless you moved the bung, that doesnt compute. Your pressure makes no difference, the o2 does not care about back pressure in the system. I still don't have cats and still don't have any O2 codes, 7-8 years and counting.
Fix the trouble code.
Fix the trouble code.
07-15-2019, 08:13 AM
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Ok you figure it out since you know how it all works together.
07-15-2019, 11:23 AM
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Can you not read I have an issue on startup that has been there since day one no codes then I put a new exhaust on then It threw I know it’s an issue but I’m not concerned about that right now I’ve got a bigger fish to fry
07-15-2019, 01:10 PM
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You pull the datastream and look at the values the computer sees. That is step 1. Do it. Go buy the scanner. Only CTS/MAF/TPS and IAC are being used at startup. Its in open loop. If the coolant temp the ECM sees is wrong, then it'll die. If the TPS isn't at 0.54 at idle, then something is wrong with it. If the IAC counts are too high, then it's clearly struggling. If the MAF is dead or dying, unplug it and see if the car runs better. Once the factory temp-dependent timers expire and the engine is warm, then it reads all other sensor information as it tries to go into closed loop. Meaning if your O2 is bad, then once those timers expire and it reads bad data, it likely floods and kills the engine. So if you fixed the open loop issue and can't keep it running because the o2 is so far gone, then you are no where further ahead of where you are now, because you don't even really know what is going on.
You told me it matters that you've made an exhaust change, well that is bullshit. The O2 does not care about the configuration of the exhaust system or the backpressure, it does not care if cats are present. It cares only about temperature because it cannot read properly if it cannot get to the right temp, and forces you to stay in open loop longer, so if you moved it well downstream, you will always have a problem. Aside from that, it doesn't matter at all what you do in the exhaust for your model year. So don't say that it does.
But you don't even know what the code showing the o2 fault is, which tells me you don't know how any of it works and you probably don't even know for sure that its an o2 code. So I'm wasting my time.
07-15-2019, 01:26 PM
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Can you not read what I've written in this thread so far? You need to be more descriptive of exactly what is going on with the car in the beginning so people know how to troubleshoot it.
You pull the datastream and look at the values the computer sees. That is step 1. Do it. Go buy the scanner. Only CTS/MAF/TPS and IAC are being used at startup. Its in open loop. If the coolant temp the ECM sees is wrong, then it'll die. If the TPS isn't at 0.54 at idle, then something is wrong with it. If the IAC counts are too high, then it's clearly struggling. If the MAF is dead or dying, unplug it and see if the car runs better. Once the factory temp-dependent timers expire and the engine is warm, then it reads all other sensor information as it tries to go into closed loop. Meaning if your O2 is bad, then once those timers expire and it reads bad data, it likely floods and kills the engine. So if you fixed the open loop issue and can't keep it running because the o2 is so far gone, then you are no where further ahead of where you are now, because you don't even really know what is going on.
You told me it matters that you've made an exhaust change, well that is bullshit. The O2 does not care about the configuration of the exhaust system or the backpressure, it does not care if cats are present. It cares only about temperature because it cannot read properly if it cannot get to the right temp, and forces you to stay in open loop longer, so if you moved it well downstream, you will always have a problem. Aside from that, it doesn't matter at all what you do in the exhaust for your model year. So don't say that it does.
But you don't even know what the code showing the o2 fault is, which tells me you don't know how any of it works and you probably don't even know for sure that its an o2 code. So I'm wasting my time.
You pull the datastream and look at the values the computer sees. That is step 1. Do it. Go buy the scanner. Only CTS/MAF/TPS and IAC are being used at startup. Its in open loop. If the coolant temp the ECM sees is wrong, then it'll die. If the TPS isn't at 0.54 at idle, then something is wrong with it. If the IAC counts are too high, then it's clearly struggling. If the MAF is dead or dying, unplug it and see if the car runs better. Once the factory temp-dependent timers expire and the engine is warm, then it reads all other sensor information as it tries to go into closed loop. Meaning if your O2 is bad, then once those timers expire and it reads bad data, it likely floods and kills the engine. So if you fixed the open loop issue and can't keep it running because the o2 is so far gone, then you are no where further ahead of where you are now, because you don't even really know what is going on.
You told me it matters that you've made an exhaust change, well that is bullshit. The O2 does not care about the configuration of the exhaust system or the backpressure, it does not care if cats are present. It cares only about temperature because it cannot read properly if it cannot get to the right temp, and forces you to stay in open loop longer, so if you moved it well downstream, you will always have a problem. Aside from that, it doesn't matter at all what you do in the exhaust for your model year. So don't say that it does.
But you don't even know what the code showing the o2 fault is, which tells me you don't know how any of it works and you probably don't even know for sure that its an o2 code. So I'm wasting my time.
07-15-2019, 08:02 PM
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07-16-2019, 06:53 AM
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How much do you think the "fancy equipment" costs and how much have you spent and will you spend throwing parts at the problem till stomething sticks? You can buy a scanner, not a code reader, which is a fancy paper clip HERE. $75 for that piece of "fancy equipment".
07-16-2019, 07:26 AM
#33
Burning Brakes
Gentlemen.....let's not get frustrated. We all have the same goal here.
Vader, thanks for the VERY informative post. I think less than 1 in a few hundred Corvette owners know how the system works like you do. Awesome!
Jared, go find that scanner!
I learned a lot today!
Vader, thanks for the VERY informative post. I think less than 1 in a few hundred Corvette owners know how the system works like you do. Awesome!
Jared, go find that scanner!
I learned a lot today!
07-20-2019, 10:49 PM
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[QUOTE=aklim;1599761422]How much do you think the "fancy equipment" costs and how much have you spent and will you spend throwing parts at the problem till stomething sticks? You can buy a scanner, not a code reader, which is a fancy paper clip HERE. $75 for that piece of "fancy equipment".[/QUOTESorry for being idle for so limg I finally was able to fine some things out I have ZERO O2 sensor problems I was mistaken and I apologize I had two codes Code 22 for low TPS voltage so I adjusted the sensor and I had code 36 ignition circuit failure or something so far it has started up every time I will keep you updated
07-20-2019, 11:55 PM
#35
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[QUOTE=JaredAwells;1599802394]
Why do you have a code 22? Was the bolt loosened or what?
https://www.corvetteforum.com/forums...ay-issues.html
How much do you think the "fancy equipment" costs and how much have you spent and will you spend throwing parts at the problem till stomething sticks? You can buy a scanner, not a code reader, which is a fancy paper clip HERE. $75 for that piece of "fancy equipment".[/QUOTESorry for being idle for so limg I finally was able to fine some things out I have ZERO O2 sensor problems I was mistaken and I apologize I had two codes Code 22 for low TPS voltage so I adjusted the sensor and I had code 36 ignition circuit failure or something so far it has started up every time I will keep you updated
https://www.corvetteforum.com/forums...ay-issues.html
07-21-2019, 01:49 AM
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[QUOTE=aklim;1599802670]
Why do you have a code 22? Was the bolt loosened or what?
https://www.corvetteforum.com/forums...ay-issues.html
No they were tight the previous owner installed it I don’t think he had it set at the right angle
Why do you have a code 22? Was the bolt loosened or what?
https://www.corvetteforum.com/forums...ay-issues.html
07-24-2019, 03:44 PM
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After a few days of working flawlessly it is back to not wanting to stay running the TPS is new and set right so now I’m left with my ignition code hopefully this will be it
