Unusually High Idle.. (99 SS Auto)
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Unusually High Idle.. (99 SS Auto) First and foremost I have pretty much read all of the high idle threads on here. I have learned a few things which at first I thought, "YES" that's probably just the problem but, nope. Just did a bunch of things like vacuum leak checks, and also an idle relearn(twice)(as well as left the battery unplugged one night and left the PMC IGN fuse out for a whole night also). Still have the same problem.
Problem: Turn the car on, jumps to about 1200RPM. I thought okay no biggy it's just warming up. As it warms up it stars increasing in RPM. After the car is at running temperature it is idling at 1400 almost 1500RPM in park!!!! When I shift into reverse or a drive gear it literally neutral drops itself.
About my motor: It's 99 SS with an Auto. I put a new tranny in it. The motor I cleaned up and put new gaskets on. I also put pacesetter long tubes with NO lines on them. I removed ALL smog stuff. I plugged the top of the intake. I am also running pretty much straight pipe(about 3ft of 2.5" pipe with turn downs [temporary]) and only using the two front O2 sensors(drives side with O2 extenders). Motor is not tuned yet.
I checked for vacuum leaks and am pretty sure I don't have any. There was a T fitting with a vacuum line going from somewhere at the rear end to the tranny that I hook the other side back to the tranny but, still not quite sure where the other line going from the T fitting goes to. So I just capped it. I did have to pull off the TB and clean it. I read that the electric ones and get messed up from being cleaned, yet this is an LS1 TB. Any idea's?
Weird T fitting
Motor(sorry for the night pics)
Problem: Turn the car on, jumps to about 1200RPM. I thought okay no biggy it's just warming up. As it warms up it stars increasing in RPM. After the car is at running temperature it is idling at 1400 almost 1500RPM in park!!!! When I shift into reverse or a drive gear it literally neutral drops itself.
About my motor: It's 99 SS with an Auto. I put a new tranny in it. The motor I cleaned up and put new gaskets on. I also put pacesetter long tubes with NO lines on them. I removed ALL smog stuff. I plugged the top of the intake. I am also running pretty much straight pipe(about 3ft of 2.5" pipe with turn downs [temporary]) and only using the two front O2 sensors(drives side with O2 extenders). Motor is not tuned yet.
I checked for vacuum leaks and am pretty sure I don't have any. There was a T fitting with a vacuum line going from somewhere at the rear end to the tranny that I hook the other side back to the tranny but, still not quite sure where the other line going from the T fitting goes to. So I just capped it. I did have to pull off the TB and clean it. I read that the electric ones and get messed up from being cleaned, yet this is an LS1 TB. Any idea's?
Weird T fitting
Motor(sorry for the night pics)
Last edited by CAL99SS; Sep 22, 2012 at 11:11 PM.
I believe the weird t fitting is some kind of vent to the tranny. It was open on my car too and I left it that way. I don't think you should cap it.
I'm not familiar with the 99 but the blockoff above your tb appears to only have on bolt, is that normal? .Do your AC vents change position? How did you block the little vacuum line and solenoid that open and close the air system?
I'm not familiar with the 99 but the blockoff above your tb appears to only have on bolt, is that normal? .Do your AC vents change position? How did you block the little vacuum line and solenoid that open and close the air system?
I know that you say that you have done vacuum tests but have you just tried spraying brake cleaner around the intake area while the car is running? That could possibly show an area that is taking in air where it shouldn't be.
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I believe the weird t fitting is some kind of vent to the tranny. It was open on my car too and I left it that way. I don't think you should cap it.
I'm not familiar with the 99 but the blockoff above your tb appears to only have on bolt, is that normal? .Do your AC vents change position? How did you block the little vacuum line and solenoid that open and close the air system?
I'm not familiar with the 99 but the blockoff above your tb appears to only have on bolt, is that normal? .Do your AC vents change position? How did you block the little vacuum line and solenoid that open and close the air system?
That's kinda interesting. Not sure I know what you mean about that air system having any vacuum or solenoid. That might just be my problem. Please explain more so I know what to look for. Thanks!
I thought of that method but my motor is super clean and I didn't really want to get it very dirty with starting fluid. I'm pretty sure there's nothing at the front. At this stage its worth the try. I will try it now.
First question is do your vents transition from floor to dash when you switch the ****? If they don't, this is your problem, if they do it slowly it might also be your problem.
On the back of the intake there are two smaller vacuum lines that are tee'd together. One controls your vents, the other connects to a little solenoid on the drivers side above the booster. The solenoid has a red connector and a second shorter vacuum line that goes to a little UFO looking thing in the AIR line. Anyway, the long vacuum line that connects the solenoid to the intake via the tee must be capped. Some folks disconnect the electrical from the solenoid and cap the nipple that connects the short hose to the UFO. That way is more reliable because it is redundant as the solenoid and cap provide sealing.
On the back of the intake there are two smaller vacuum lines that are tee'd together. One controls your vents, the other connects to a little solenoid on the drivers side above the booster. The solenoid has a red connector and a second shorter vacuum line that goes to a little UFO looking thing in the AIR line. Anyway, the long vacuum line that connects the solenoid to the intake via the tee must be capped. Some folks disconnect the electrical from the solenoid and cap the nipple that connects the short hose to the UFO. That way is more reliable because it is redundant as the solenoid and cap provide sealing.
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First question is do your vents transition from floor to dash when you switch the ****? If they don't, this is your problem, if they do it slowly it might also be your problem.
On the back of the intake there are two smaller vacuum lines that are tee'd together. One controls your vents, the other connects to a little solenoid on the drivers side above the booster. The solenoid has a red connector and a second shorter vacuum line that goes to a little UFO looking thing in the AIR line. Anyway, the long vacuum line that connects the solenoid to the intake via the tee must be capped. Some folks disconnect the electrical from the solenoid and cap the nipple that connects the short hose to the UFO. That way is more reliable because it is redundant as the solenoid and cap provide sealing.
On the back of the intake there are two smaller vacuum lines that are tee'd together. One controls your vents, the other connects to a little solenoid on the drivers side above the booster. The solenoid has a red connector and a second shorter vacuum line that goes to a little UFO looking thing in the AIR line. Anyway, the long vacuum line that connects the solenoid to the intake via the tee must be capped. Some folks disconnect the electrical from the solenoid and cap the nipple that connects the short hose to the UFO. That way is more reliable because it is redundant as the solenoid and cap provide sealing.
I don't see any solenoid or red connector.
Is this the thing you were talking about or is it physically on the back of the intake?
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My cars motor is not configured like the on in this picture above.
Mine has the T valve on the back of the intake. One is big one is small. The big one goes right into the brake booster on the drivers side and the small on goes to the passenger side and then goes up inside the main wiring harness. It then goes out near the air con connection shown in the post above this one. It goes into another T valve. With one hose leading into the firewall and one going back into the main part of the wiring harness leading toward the front of the car.
Has for a solenoid with an electrical plug I can't seem to find.
Or do I just cap it here and unplug that plug on top of the intake T valve?
Sorry for sounding so stupid, not sure why I'm so lost on this.. 8(
Last edited by CAL99SS; Sep 24, 2012 at 12:00 AM.
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plug them all back in, you shouldn't unplug them when installing headers. i capped mine and couldn't figure out why my main ac vents never worked but once i plugged it back in boom they worked perfectly again 
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I'm just worried about the idle right now. I purposely unplugged the AC ish. I don't need AC in my location but, maybe a month out of the year. So its gotta go for the sake of a couple more HP's and less junk weight.
The one going to the firewall should be ok provided you didn't break anything. The one going back to the engine compartment is the one you need to locate. If possible get some pliers on the **** and see I'd you can switch the AC off the floor...but you also need to locate the other end of that second small line and make sure it is capped.
The UFO thing would have been removed with you air tubes. It is big, like 3" diameter. You did label the solenoid I was talking about above.
The UFO thing would have been removed with you air tubes. It is big, like 3" diameter. You did label the solenoid I was talking about above.
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The one going to the firewall should be ok provided you didn't break anything. The one going back to the engine compartment is the one you need to locate. If possible get some pliers on the **** and see I'd you can switch the AC off the floor...but you also need to locate the other end of that second small line and make sure it is capped.
The UFO thing would have been removed with you air tubes. It is big, like 3" diameter. You did label the solenoid I was talking about above.
The UFO thing would have been removed with you air tubes. It is big, like 3" diameter. You did label the solenoid I was talking about above.
so the car idled fine before then you put new gaskets and LT's on and the idle went to this? did you tighten the bolts to torque spec and sequence (tightening bolts front to back or back to front is not in sequence btw)? which gaskets did you install?
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I did all the gaskets except head gaskets. I am very familiar with the proper way to torque everything back down. What threw me off is that I did label EVERYTHING. Except when I cleaned out the motor compartment, I sprayed simple green everywhere in it and pressure washed it. I guess the simple green removed all of the inc on my masking tape labels. 8( Most of everything was common sense but there was a few things that through me off.
I am going to cap that T valve thing and do another relearn and see what happens. Thanks for all the input guys!
I am going to cap that T valve thing and do another relearn and see what happens. Thanks for all the input guys!
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I just capped of that thing you were telling me about at the T valve and nothing no change. I made sure the back was connected and plugged the part which we were speaking of. No change still. I am absolutely puzzled. I also sprayed starting fluid all over it and didn't notice any spike in RPM at warm temp idle.
I must remind its idling when warm around 1500RPM. This is ridiculous.
I must remind its idling when warm around 1500RPM. This is ridiculous.
Did your car have the smog pump and air fittings fully connected prior to headers? If so did you plug the 1 vacuum line going to the solenoid type thing on the drivers side?
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My car does not have any solenoid on the drivers side. The one any only vacuum line located on the drivers side is going to the brake booster. This was completely unchanged and was like this when it was bone stock.
Is it still making the loud sucking sound? I'm out of my depth at this point, but you might check that the tb blade is closing all the way. If you are sure no vacuum leaks an tb is definitely closed, maybe check the iac...I don't know anything about that...but that sucking sound is a clueto something.
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Is it still making the loud sucking sound? I'm out of my depth at this point, but you might check that the tb blade is closing all the way. If you are sure no vacuum leaks an tb is definitely closed, maybe check the iac...I don't know anything about that...but that sucking sound is a clueto something.