Bad optispark? youtube video to help
09-13-2013, 06:26 PM
#1
Senior Member
Thread Starter
Bad optispark? youtube video to help
First off. its a 1993 lt1 in a 88 camaro. Speed density
The problem just started. Replaced the plugs, wires, fuel filter, and fuel pump within the last month. It won't stay running without my foot on the gas. And if I can get it to run it won't run above 500rpm then die shortly. It has the symptoms of a bad opti but I don't want to throw parts at it. I checked the codes just a vvs sensor and evap canister code nothing major. Keep in mind I don't have tools and the only knowledge I have about cars is from this and other sites. So my mechanic will have to look at it for me. Thanks Friday the 13th now I can't go to the track tonight
If I didn't answer enough questions or left some out ask away please thanks.
The problem just started. Replaced the plugs, wires, fuel filter, and fuel pump within the last month. It won't stay running without my foot on the gas. And if I can get it to run it won't run above 500rpm then die shortly. It has the symptoms of a bad opti but I don't want to throw parts at it. I checked the codes just a vvs sensor and evap canister code nothing major. Keep in mind I don't have tools and the only knowledge I have about cars is from this and other sites. So my mechanic will have to look at it for me. Thanks Friday the 13th now I can't go to the track tonight
If I didn't answer enough questions or left some out ask away please thanks.
09-15-2013, 10:22 AM
#2
Re: Bad optispark? youtube video to help
J - That's probably NOT an Opti problem since it will run with some additional air and fuel from the throttle being held. A failing/weak Opti just wouldn't care, and might actually (usually) act worse under load.
Just by the few symptoms you describe and what can be seen from the video, I'd suspect the air rate is not being controlled by the IAC as it should, or the air rate is not being measured by the MAF properly.
If you haven't already done so, remove the intake bellows from the front of the throttle body and inspect the throttle bores and idle air passages. If there is varnish buildup around the throttle plates (obvious when the throttle is held open so you can see in) and if there is buildup in the IAC air passages, it won't get adequate air in the closed throttle position. Your holding the throttle open slightly solves that, but it should do it all by itself.
If you discover buildup, get some spray cleaner for TBs or carburetors, hold the throttle open, and flush out the deposits. The first start after doing this will be difficult since there will be a lot of liquid in the plenum, but it should clear up quickly once it runs for a few seconds.
If there is varnish in the throttle bores and on the plates, there will also be buildup on the IAC. The BEST thing to do is to remove the IAC and clean it. If you search the site you should find numerous posts outlining that procedure.
CAUTION !! Be VERY careful with the two Torx screws holding the IAC to the throttle body. There is a better than 50% chance they are seized into the aluminum in the TB housing. Get some good penetrating oil (I'd suggest Kroil or B'Laster PB) and liberally soak the screws before attempting removal. It would be best to soak the screws a day or more before attempting removal, and getting the engine up to temperature and allowing it to cool, then applying more penetrating oil.
Even after applying penetrating oil, ONLY use a good quality, well-fitting Torx bit to remove the screws. Having had to remove the TB, drill out the hardened screws, and re-tapping the holes more than once, I thought I would save you some of the frustration.
When you reassemble, apply anti-seize compound to the screw threads and run them into and out of there holes a couple times to distribute the compound before final tightening of the screws. This will make any future removal a LOT easier. Why the factory did not apply some sort of compound is beyond me, but they didn't in these positions, while they DID in others.
Just by the few symptoms you describe and what can be seen from the video, I'd suspect the air rate is not being controlled by the IAC as it should, or the air rate is not being measured by the MAF properly.
If you haven't already done so, remove the intake bellows from the front of the throttle body and inspect the throttle bores and idle air passages. If there is varnish buildup around the throttle plates (obvious when the throttle is held open so you can see in) and if there is buildup in the IAC air passages, it won't get adequate air in the closed throttle position. Your holding the throttle open slightly solves that, but it should do it all by itself.
If you discover buildup, get some spray cleaner for TBs or carburetors, hold the throttle open, and flush out the deposits. The first start after doing this will be difficult since there will be a lot of liquid in the plenum, but it should clear up quickly once it runs for a few seconds.
If there is varnish in the throttle bores and on the plates, there will also be buildup on the IAC. The BEST thing to do is to remove the IAC and clean it. If you search the site you should find numerous posts outlining that procedure.
CAUTION !! Be VERY careful with the two Torx screws holding the IAC to the throttle body. There is a better than 50% chance they are seized into the aluminum in the TB housing. Get some good penetrating oil (I'd suggest Kroil or B'Laster PB) and liberally soak the screws before attempting removal. It would be best to soak the screws a day or more before attempting removal, and getting the engine up to temperature and allowing it to cool, then applying more penetrating oil.
Even after applying penetrating oil, ONLY use a good quality, well-fitting Torx bit to remove the screws. Having had to remove the TB, drill out the hardened screws, and re-tapping the holes more than once, I thought I would save you some of the frustration.
When you reassemble, apply anti-seize compound to the screw threads and run them into and out of there holes a couple times to distribute the compound before final tightening of the screws. This will make any future removal a LOT easier. Why the factory did not apply some sort of compound is beyond me, but they didn't in these positions, while they DID in others.
09-15-2013, 12:57 PM
#3
Senior Member
Thread Starter
Re: Bad optispark? youtube video to help
J - That's probably NOT an Opti problem since it will run with some additional air and fuel from the throttle being held. A failing/weak Opti just wouldn't care, and might actually (usually) act worse under load.
Just by the few symptoms you describe and what can be seen from the video, I'd suspect the air rate is not being controlled by the IAC as it should, or the air rate is not being measured by the MAF properly.
If you haven't already done so, remove the intake bellows from the front of the throttle body and inspect the throttle bores and idle air passages. If there is varnish buildup around the throttle plates (obvious when the throttle is held open so you can see in) and if there is buildup in the IAC air passages, it won't get adequate air in the closed throttle position. Your holding the throttle open slightly solves that, but it should do it all by itself.
If you discover buildup, get some spray cleaner for TBs or carburetors, hold the throttle open, and flush out the deposits. The first start after doing this will be difficult since there will be a lot of liquid in the plenum, but it should clear up quickly once it runs for a few seconds.
If there is varnish in the throttle bores and on the plates, there will also be buildup on the IAC. The BEST thing to do is to remove the IAC and clean it. If you search the site you should find numerous posts outlining that procedure.
CAUTION !! Be VERY careful with the two Torx screws holding the IAC to the throttle body. There is a better than 50% chance they are seized into the aluminum in the TB housing. Get some good penetrating oil (I'd suggest Kroil or B'Laster PB) and liberally soak the screws before attempting removal. It would be best to soak the screws a day or more before attempting removal, and getting the engine up to temperature and allowing it to cool, then applying more penetrating oil.
Even after applying penetrating oil, ONLY use a good quality, well-fitting Torx bit to remove the screws. Having had to remove the TB, drill out the hardened screws, and re-tapping the holes more than once, I thought I would save you some of the frustration.
When you reassemble, apply anti-seize compound to the screw threads and run them into and out of there holes a couple times to distribute the compound before final tightening of the screws. This will make any future removal a LOT easier. Why the factory did not apply some sort of compound is beyond me, but they didn't in these positions, while they DID in others.
Just by the few symptoms you describe and what can be seen from the video, I'd suspect the air rate is not being controlled by the IAC as it should, or the air rate is not being measured by the MAF properly.
If you haven't already done so, remove the intake bellows from the front of the throttle body and inspect the throttle bores and idle air passages. If there is varnish buildup around the throttle plates (obvious when the throttle is held open so you can see in) and if there is buildup in the IAC air passages, it won't get adequate air in the closed throttle position. Your holding the throttle open slightly solves that, but it should do it all by itself.
If you discover buildup, get some spray cleaner for TBs or carburetors, hold the throttle open, and flush out the deposits. The first start after doing this will be difficult since there will be a lot of liquid in the plenum, but it should clear up quickly once it runs for a few seconds.
If there is varnish in the throttle bores and on the plates, there will also be buildup on the IAC. The BEST thing to do is to remove the IAC and clean it. If you search the site you should find numerous posts outlining that procedure.
CAUTION !! Be VERY careful with the two Torx screws holding the IAC to the throttle body. There is a better than 50% chance they are seized into the aluminum in the TB housing. Get some good penetrating oil (I'd suggest Kroil or B'Laster PB) and liberally soak the screws before attempting removal. It would be best to soak the screws a day or more before attempting removal, and getting the engine up to temperature and allowing it to cool, then applying more penetrating oil.
Even after applying penetrating oil, ONLY use a good quality, well-fitting Torx bit to remove the screws. Having had to remove the TB, drill out the hardened screws, and re-tapping the holes more than once, I thought I would save you some of the frustration.
When you reassemble, apply anti-seize compound to the screw threads and run them into and out of there holes a couple times to distribute the compound before final tightening of the screws. This will make any future removal a LOT easier. Why the factory did not apply some sort of compound is beyond me, but they didn't in these positions, while they DID in others.
Wow. That was very helpful. The guys over at ls1lt1.com also said they don't think it's the opti.
Think i may have left this out. I had this problem once before a couple days ago. Thought it was out a gas and I work at a gas station (where it stopped working) got some gas that didnt work. Unplugged the negative battery cable to reset the computer to try to trick the computer so I could get home. Fail. Unplugged the iac held the gas at the right rpm for idle for a minute and it stayed running. I plugged up the iac and went home. Drove it for 2 days no problems. Had to go to work and ended up making that video instead. I looked at my intake and somwehow it was disconnected right before the iac. I can't get the iac out the intake because I don't want to break it.
So a good iac cleaning and my problems should cease?
09-15-2013, 04:15 PM
#4
Re: Bad optispark? youtube video to help
There's no way to guaranty that cleaning the IAC will solve the problem. However, if the IAC is dirty and sticking or the passages are plugged, I can guaranty that nothing else you do will solve it. In short, you might as well clean the TB and IAC anyway, and it MAY solve the problem.
If you can't get the IAC removed, you might try to blast some cleaner through the air passage hole in the bottom center of the TB. I just pulled a dusty spare off my shelf identified the hole with an arrow:
It would be tough to accomplish, since LT1s don't like to run without a MAF signal, but it might be most effective to do this while the engine is running and intake bellows is removed.
I know this may be a sucky day to be doing that if you're outdoors. 3 hours north of you it's been raining all day.
If you can't get the IAC removed, you might try to blast some cleaner through the air passage hole in the bottom center of the TB. I just pulled a dusty spare off my shelf identified the hole with an arrow:
It would be tough to accomplish, since LT1s don't like to run without a MAF signal, but it might be most effective to do this while the engine is running and intake bellows is removed.
I know this may be a sucky day to be doing that if you're outdoors. 3 hours north of you it's been raining all day.
09-18-2013, 07:17 PM
#5
Senior Member
Thread Starter
Re: Bad optispark? youtube video to help
J - That's probably NOT an Opti problem since it will run with some additional air and fuel from the throttle being held. A failing/weak Opti just wouldn't care, and might actually (usually) act worse under load.
Just by the few symptoms you describe and what can be seen from the video, I'd suspect the air rate is not being controlled by the IAC as it should, or the air rate is not being measured by the MAF properly.
If you haven't already done so, remove the intake bellows from the front of the throttle body and inspect the throttle bores and idle air passages. If there is varnish buildup around the throttle plates (obvious when the throttle is held open so you can see in) and if there is buildup in the IAC air passages, it won't get adequate air in the closed throttle position. Your holding the throttle open slightly solves that, but it should do it all by itself.
If you discover buildup, get some spray cleaner for TBs or carburetors, hold the throttle open, and flush out the deposits. The first start after doing this will be difficult since there will be a lot of liquid in the plenum, but it should clear up quickly once it runs for a few seconds.
If there is varnish in the throttle bores and on the plates, there will also be buildup on the IAC. The BEST thing to do is to remove the IAC and clean it. If you search the site you should find numerous posts outlining that procedure.
CAUTION !! Be VERY careful with the two Torx screws holding the IAC to the throttle body. There is a better than 50% chance they are seized into the aluminum in the TB housing. Get some good penetrating oil (I'd suggest Kroil or B'Laster PB) and liberally soak the screws before attempting removal. It would be best to soak the screws a day or more before attempting removal, and getting the engine up to temperature and allowing it to cool, then applying more penetrating oil.
Even after applying penetrating oil, ONLY use a good quality, well-fitting Torx bit to remove the screws. Having had to remove the TB, drill out the hardened screws, and re-tapping the holes more than once, I thought I would save you some of the frustration.
When you reassemble, apply anti-seize compound to the screw threads and run them into and out of there holes a couple times to distribute the compound before final tightening of the screws. This will make any future removal a LOT easier. Why the factory did not apply some sort of compound is beyond me, but they didn't in these positions, while they DID in others.
Just by the few symptoms you describe and what can be seen from the video, I'd suspect the air rate is not being controlled by the IAC as it should, or the air rate is not being measured by the MAF properly.
If you haven't already done so, remove the intake bellows from the front of the throttle body and inspect the throttle bores and idle air passages. If there is varnish buildup around the throttle plates (obvious when the throttle is held open so you can see in) and if there is buildup in the IAC air passages, it won't get adequate air in the closed throttle position. Your holding the throttle open slightly solves that, but it should do it all by itself.
If you discover buildup, get some spray cleaner for TBs or carburetors, hold the throttle open, and flush out the deposits. The first start after doing this will be difficult since there will be a lot of liquid in the plenum, but it should clear up quickly once it runs for a few seconds.
If there is varnish in the throttle bores and on the plates, there will also be buildup on the IAC. The BEST thing to do is to remove the IAC and clean it. If you search the site you should find numerous posts outlining that procedure.
CAUTION !! Be VERY careful with the two Torx screws holding the IAC to the throttle body. There is a better than 50% chance they are seized into the aluminum in the TB housing. Get some good penetrating oil (I'd suggest Kroil or B'Laster PB) and liberally soak the screws before attempting removal. It would be best to soak the screws a day or more before attempting removal, and getting the engine up to temperature and allowing it to cool, then applying more penetrating oil.
Even after applying penetrating oil, ONLY use a good quality, well-fitting Torx bit to remove the screws. Having had to remove the TB, drill out the hardened screws, and re-tapping the holes more than once, I thought I would save you some of the frustration.
When you reassemble, apply anti-seize compound to the screw threads and run them into and out of there holes a couple times to distribute the compound before final tightening of the screws. This will make any future removal a LOT easier. Why the factory did not apply some sort of compound is beyond me, but they didn't in these positions, while they DID in others.
Ill give a update to let you know how things are still going.
09-25-2013, 09:57 PM
#6
Senior Member
Thread Starter
Re: Bad optispark? youtube video to help
So the problem returned. First start of the day, perfect. Ran felt strong and sounded good. Ram errornds came home and parked it. About an hour later, came down to start it and the same exact problem as before. Sprayed down the Iac, throttle body and intake and it stayed running at about 500 rpms. Ran to the gas station, cut it off. Got gas it started to about 500rpms and i drove it home. It idled at 500 rpms when I drove it as well. Any thoughts, maybe replace the iac?
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