Need help diagnosing a problem in my L98 '87
Thread Starter
Instructor
Joined: Sep 2013
Posts: 118
Likes: 2
Need help diagnosing a problem in my L98 '87
My car is bone stock with the exception of straight pipes, no cats, magnaflow mufflers with what I believe to be LT1 style tips , and a K&N air filter.
My car has a kill switch and I use it frequently. Well what is funny is that when I don't use it, my car starts hard with a check engine light coming on. when I start it after turning off my kill switch it fires right up and doesn't have a problem. My idle does surge , I know it's a vacuum leak so I checked my CSI and found that it was a little lose. the problem is that the start up is very hard and I can't use the AC straight from start up as it will kill the car once I let off the gas coming to a stop for example, it works but if I were to rev it to about 800rpm ( I idle at 500-600 RPM in about 85-95* weather in south Florida) it dies and has a very hard time cranking up. I plan on cleaning the MAF sensor and the IAC. Would that solve the problem ? I also do plan on removing the CSI system.
My car has a kill switch and I use it frequently. Well what is funny is that when I don't use it, my car starts hard with a check engine light coming on. when I start it after turning off my kill switch it fires right up and doesn't have a problem. My idle does surge , I know it's a vacuum leak so I checked my CSI and found that it was a little lose. the problem is that the start up is very hard and I can't use the AC straight from start up as it will kill the car once I let off the gas coming to a stop for example, it works but if I were to rev it to about 800rpm ( I idle at 500-600 RPM in about 85-95* weather in south Florida) it dies and has a very hard time cranking up. I plan on cleaning the MAF sensor and the IAC. Would that solve the problem ? I also do plan on removing the CSI system.
Racer
Joined: Sep 2011
Posts: 400
Likes: 5
From: Bakersfield Ca
My car is bone stock with the exception of straight pipes, no cats, magnaflow mufflers with what I believe to be LT1 style tips , and a K&N air filter.
My car has a kill switch and I use it frequently. Well what is funny is that when I don't use it, my car starts hard with a check engine light coming on. when I start it after turning off my kill switch it fires right up and doesn't have a problem. My idle does surge , I know it's a vacuum leak so I checked my CSI and found that it was a little lose. the problem is that the start up is very hard and I can't use the AC straight from start up as it will kill the car once I let off the gas coming to a stop for example, it works but if I were to rev it to about 800rpm ( I idle at 500-600 RPM in about 85-95* weather in south Florida) it dies and has a very hard time cranking up. I plan on cleaning the MAF sensor and the IAC. Would that solve the problem ? I also do plan on removing the CSI system.
My car has a kill switch and I use it frequently. Well what is funny is that when I don't use it, my car starts hard with a check engine light coming on. when I start it after turning off my kill switch it fires right up and doesn't have a problem. My idle does surge , I know it's a vacuum leak so I checked my CSI and found that it was a little lose. the problem is that the start up is very hard and I can't use the AC straight from start up as it will kill the car once I let off the gas coming to a stop for example, it works but if I were to rev it to about 800rpm ( I idle at 500-600 RPM in about 85-95* weather in south Florida) it dies and has a very hard time cranking up. I plan on cleaning the MAF sensor and the IAC. Would that solve the problem ? I also do plan on removing the CSI system.
Is the kill switch to bypass the VATS. DO you still have to have clutch to floor or is yours an auto.
Last edited by AJ123; Oct 18, 2014 at 09:21 PM. Reason: more info
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
What error codes is the ECM storing?
How to retrieve them:
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Most likely is a problem with the CTS. If the connection is open (broken wire or corroded connector pin) or the CTS is bad the ECM will think the coolant is at -40° and all kinds of weird things happen.
You might have an error code 32 caused by the ECM thinking the EGR temperature switch is closed at startup.
How to retrieve them:
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Most likely is a problem with the CTS. If the connection is open (broken wire or corroded connector pin) or the CTS is bad the ECM will think the coolant is at -40° and all kinds of weird things happen.
You might have an error code 32 caused by the ECM thinking the EGR temperature switch is closed at startup.
Thread Starter
Instructor
Joined: Sep 2013
Posts: 118
Likes: 2
What error codes is the ECM storing?
How to retrieve them:
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Most likely is a problem with the CTS. If the connection is open (broken wire or corroded connector pin) or the CTS is bad the ECM will think the coolant is at -40° and all kinds of weird things happen.
You might have an error code 32 caused by the ECM thinking the EGR temperature switch is closed at startup.
How to retrieve them:
http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm
What they mean:
http://forums.corvetteforum.com/1576116036-post35.html
Most likely is a problem with the CTS. If the connection is open (broken wire or corroded connector pin) or the CTS is bad the ECM will think the coolant is at -40° and all kinds of weird things happen.
You might have an error code 32 caused by the ECM thinking the EGR temperature switch is closed at startup.
My TPS isn't adjusted 100% either.
Thread Starter
Instructor
Joined: Sep 2013
Posts: 118
Likes: 2
I had somewhat similar problem only mine wouldn't turn over. It was intermittant which drove me crazy until I finally replaced the starter and everything has been fine since. There are several potential problem you could have. I did replace the starter enable relay which is behind the middle a/c vents when I was diagnosing my start problem. Could be a loose ground. Or you could have a fuel pump problem. - See more at: http://www.corvetteactioncenter.com/....MEMD8kF7.dpuf
Is the kill switch to bypass the VATS. DO you still have to have clutch to floor or is yours an auto.
Is the kill switch to bypass the VATS. DO you still have to have clutch to floor or is yours an auto.
Racer
Joined: Sep 2011
Posts: 400
Likes: 5
From: Bakersfield Ca
Take your time work on 1 code at a time. Sounds like you bought a money pit like my 87.
The dash board are a problem replaced mine twice. Don't hit the dash above it to make it turn back on. Makes it worse. There are youtube videos that tell you how to repair and fix basic problems. Setting my TPS turned into a night mare with the sensor finally being the problem. Now tracing wires from ECM to TPS see if there is a break in wire My ecm is on warranty so while checking on wires my ecm will be here Tue.
Remove and clean MAF with correct spray. Do you know how to clear codes by unhooking the battery and let residual electrify drain off . Some people use horn to drain it off faster with the battery un hooked
\
The dash board are a problem replaced mine twice. Don't hit the dash above it to make it turn back on. Makes it worse. There are youtube videos that tell you how to repair and fix basic problems. Setting my TPS turned into a night mare with the sensor finally being the problem. Now tracing wires from ECM to TPS see if there is a break in wire My ecm is on warranty so while checking on wires my ecm will be here Tue.
Remove and clean MAF with correct spray. Do you know how to clear codes by unhooking the battery and let residual electrify drain off . Some people use horn to drain it off faster with the battery un hooked
Last edited by AJ123; Oct 19, 2014 at 12:21 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Try resetting the ECM and see what error codes show up. You will get error code 42 when setting the timing, so that one should go away. Open this connector for a second or so to reset the ECM:
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