View Poll Results: What mods have you done?
No mods that would effect the idle
66
58.41%
Torque Converter
3
2.65%
Intake w/o ECU
18
15.93%
Intake w/ ECU
11
9.73%
Torque Converter and Intake w/o ECU
1
0.88%
Torque Converter and Intake w/ ECU
14
12.39%
Voters: 113. You may not vote on this poll
Low Idle Investigation
05-13-03, 06:00 PM
#16
Lexus Fanatic
iTrader: (20)
Re: My car is bone stock and has it sometimes
Originally posted by Guitarman
The parking light thing is fine, except for the fact you don't want to forget you left them on when you park.
The parking light thing is fine, except for the fact you don't want to forget you left them on when you park.
05-13-03, 09:26 PM
#17
Awesome
It's not a problem, they turn off automatically after a minute or so.
05-14-03, 08:15 AM
#18
I have DRL on my '99 GS400, and it suffers from the low idle malady.
My theory agrees with what I've seen here: it's probably an engine computer programming
issue. I suspect that Lexus/Toyota would like to avoid modifications to correct the problem
because any modifications--especially one that alters engine idle--may require a recertification of the emissions control system--a process which I suspect is time-consuming and pretty expensive. (Just a
theory based on experience with qual'ing computer hardware with the FCC and suspicions with nothing
to back it up :-)
My theory agrees with what I've seen here: it's probably an engine computer programming
issue. I suspect that Lexus/Toyota would like to avoid modifications to correct the problem
because any modifications--especially one that alters engine idle--may require a recertification of the emissions control system--a process which I suspect is time-consuming and pretty expensive. (Just a
theory based on experience with qual'ing computer hardware with the FCC and suspicions with nothing
to back it up :-)
05-14-03, 04:22 PM
#19
Hmmm...curiouser and curiouser,,,
Every time it seems we are getting close to a solution it seems it doesn't prove out. Thanks for the info.
At the least, I know putting my parking lights on works, and since I now don't have to worry so much about forgetting they're on, at least I have that for the time being.
Every time it seems we are getting close to a solution it seems it doesn't prove out. Thanks for the info.
At the least, I know putting my parking lights on works, and since I now don't have to worry so much about forgetting they're on, at least I have that for the time being.
02-29-04, 08:08 PM
#20
Lexus Test Driver
What's the idle you guys are getting when the car is fully warmed up? Let me rephrase that.....while you are at a complete stop in DRIVE. What's the idle? Is it between the 2nd & the 3rd line?
Is this with everything off? Well, except the daytime running lights right? Is there anyway to turn off the DRL?
I've test drove several GS4s and most of them idle between the 2nd and 3rd mark and felt fine to me. Only one was slightly rougher than the rest.....hmmmm
Is this with everything off? Well, except the daytime running lights right? Is there anyway to turn off the DRL?
I've test drove several GS4s and most of them idle between the 2nd and 3rd mark and felt fine to me. Only one was slightly rougher than the rest.....hmmmm
03-03-04, 05:16 AM
#21
Lexus Fanatic
iTrader: (20)
When the car is warmed up and I'm in drive, stopped, with climate control on and only DRLs on, my SAFC-II says my rpms are about 660.
03-03-04, 08:42 AM
#22
Lexus Test Driver
Originally posted by bitkahuna
When the car is warmed up and I'm in drive, stopped, with climate control on and only DRLs on, my SAFC-II says my rpms are about 660.
When the car is warmed up and I'm in drive, stopped, with climate control on and only DRLs on, my SAFC-II says my rpms are about 660.
03-03-04, 06:29 PM
#23
Lexus Test Driver
Damn, I need one of those RPM reading devices you guys have. In terms of the RPM gauge, what's that? The 3rd line? The 2nd line? Somewhere in between?
How about a fully warmed up car with EVERYTHING off (except for DRL.....since you can't turn them off right???). Where should the RPM be when you're fully stop in DRIVE?
How about a fully warmed up car with EVERYTHING off (except for DRL.....since you can't turn them off right???). Where should the RPM be when you're fully stop in DRIVE?
03-03-04, 06:53 PM
#24
Lexus Fanatic
iTrader: (20)
Originally posted by Cadd
Damn, I need one of those RPM reading devices you guys have. In terms of the RPM gauge, what's that? The 3rd line? The 2nd line? Somewhere in between?
Damn, I need one of those RPM reading devices you guys have. In terms of the RPM gauge, what's that? The 3rd line? The 2nd line? Somewhere in between?
I think there's 3 lines between 0 and 1 on the rpm guage, so that would be 250rpm per line. Mine is between the 2nd and 3rd line (i.e., between 500 and 750), corresponding to the 660 I mentioned.
03-03-04, 07:03 PM
#25
Lexus Test Driver
I should have thought of that 
But I don't always trust the gauges.....especially when it is either at one end or at the other end of things. If it was in the middle (i.e. 3,000 RPM), you can safely assume it's around 2,900 - 3,100RPM (since gauges aren't always accurate). But when you get down to smaller numbers (especially at the very beginning or end of the gauge's range), I don't feel confident to count lines and dividing them by 4 to get an accurate number.
Of the 6 GS400s I've test drove, only one was on/below the second line. The rest of them idled somewhere between the 2nd & 3rd line with the climate control OFF and daytime running lights ON.
How much does those RPM readers go for? Seems like a neat device to have around.
But I don't always trust the gauges.....especially when it is either at one end or at the other end of things. If it was in the middle (i.e. 3,000 RPM), you can safely assume it's around 2,900 - 3,100RPM (since gauges aren't always accurate). But when you get down to smaller numbers (especially at the very beginning or end of the gauge's range), I don't feel confident to count lines and dividing them by 4 to get an accurate number.
Of the 6 GS400s I've test drove, only one was on/below the second line. The rest of them idled somewhere between the 2nd & 3rd line with the climate control OFF and daytime running lights ON.
How much does those RPM readers go for? Seems like a neat device to have around.
03-03-04, 08:36 PM
#26
Lexus Fanatic
iTrader: (20)
You can pick up the original SAFC cheap on eBay. I have the SAFC-II, which has a few more features, which I got on eBay for $265.
03-04-04, 07:09 AM
#27
Lead Lap
Join Date: Feb 2001
Location: Dallas
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My car mimics your RPM behvaior EXACTLY. To the number and circumstance. And remember, folks, he's blown and all I'm not.
I am convinced this has NOTHING to do with modifications.
I am convinced this has NOTHING to do with modifications.
Originally posted by Mr Johnson
I don't fall into the predefined categories but I would vote for some combination of ECU programming and "issues" with the TB/MAF.
If I leave my AC on (say auto mode) I will never have a problem with low idle and my car will idle at ~750-800 RPM. If I turn off the AC while sitting at a stop (car warmed up) idle will drop to 250-350 RPM and the car will either die or else the ECU "learns" something and idle comes up to ~500 RPM. After that first "learn" my car will then always idle at ~500 RPM with no further problems. This only happens once the car is warmed up and in closed-loop mode. While "cold" no problems with idle at all.
I've been eyeing a TEC3 unit given all the great buzz around it, maybe I'll take the plunge and see if I can program it to control our cars in a "stock" manner (time is my only enemy).
I don't fall into the predefined categories but I would vote for some combination of ECU programming and "issues" with the TB/MAF.
If I leave my AC on (say auto mode) I will never have a problem with low idle and my car will idle at ~750-800 RPM. If I turn off the AC while sitting at a stop (car warmed up) idle will drop to 250-350 RPM and the car will either die or else the ECU "learns" something and idle comes up to ~500 RPM. After that first "learn" my car will then always idle at ~500 RPM with no further problems. This only happens once the car is warmed up and in closed-loop mode. While "cold" no problems with idle at all.
I've been eyeing a TEC3 unit given all the great buzz around it, maybe I'll take the plunge and see if I can program it to control our cars in a "stock" manner (time is my only enemy).
03-05-04, 10:20 PM
#28
Driver School Candidate
Join Date: Jan 2002
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Unfortunately, it seems like I am having the same issues with my newly acquired GS. I changed the plugs and found that the car now turned off at stops. I figured the plugs might be fowled a bit causing the car to idle a bit lower from time to time but that didn't change it. I am going to try and raise the idle of the car while in drive. We'll see how that helps. Let me know if anyone finds out anything.
04-03-05, 09:27 AM
#29
Pole Position
Newbie here.... just curious, has anyone changed their O2 sensors? I hear that they typically start to decline after 60k.
Also is there a milage similarity amongst problematic cars? ie, it happens after to 50k or is it a age issue, '98-'00 or something like that.
I just bought a '98 and I think I may have the problem, but it has never stopped.
Also is there a milage similarity amongst problematic cars? ie, it happens after to 50k or is it a age issue, '98-'00 or something like that.
I just bought a '98 and I think I may have the problem, but it has never stopped.
06-30-05, 02:12 PM
#30
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What is the current update of this?
I have a 93 SC4 and I'm having the a/c off idle issue, car peaks and drops, peaks and drops. When tweaking with the wires and the MAF the issue goes away, it's easy to mimic with the computer hooked up.
I have purchased another MAF, the lexus tech mentioned those are computer aligned and I'm reading people cleaned their MAF, but I don't see how they cleaned it and kept it aligned. These parts are very pricy from the dealer to replace, but I got another "said" working one for testing.
I have a 93 SC4 and I'm having the a/c off idle issue, car peaks and drops, peaks and drops. When tweaking with the wires and the MAF the issue goes away, it's easy to mimic with the computer hooked up.
I have purchased another MAF, the lexus tech mentioned those are computer aligned and I'm reading people cleaned their MAF, but I don't see how they cleaned it and kept it aligned. These parts are very pricy from the dealer to replace, but I got another "said" working one for testing.