Changing idle speed; GM tech 2.... '98 ls1........Come in Tech 2 gurus
08-28-2008, 08:29 PM
#1
Changing idle speed; GM tech 2.... '98 ls1........Come in Tech 2 gurus I'm trying to change the idle speed on a 98 camro m6, ls1, with a big cam for a friend of mine.
Can anyone enlighten me as to the proper procedure to adjust it with a GM tech 2? He wants it specifically set with the ecm.
I thought to change it you had to go into the engine data section and raise the "desired idle speed" in 25-50rpm increments, But I tried changing before on another slightly newer GM vehicle but it didn't seem to work for some reason (it didn't permanently raise the idle speed). Now I haven't tried it with this exact vehicle yet but I didn't know if there was another part to this procedure that I was unaware of, or If I was somehow in the wrong area. I'm trying to find out now because I only have a very limited amount of time with the car.
Can anyone help me out?
Ps, He is specifically looking to change the desired idle speed setting in the ecm, doesn't want to adjust the screw or drill a hole in the Tb
edit:
forgot to mention, its a trex cam, but I don't know the specs. The pcm was already tuned for the cam, but the idle speed is still a tad too, and occasionally will stall.
Can anyone enlighten me as to the proper procedure to adjust it with a GM tech 2? He wants it specifically set with the ecm.
I thought to change it you had to go into the engine data section and raise the "desired idle speed" in 25-50rpm increments, But I tried changing before on another slightly newer GM vehicle but it didn't seem to work for some reason (it didn't permanently raise the idle speed). Now I haven't tried it with this exact vehicle yet but I didn't know if there was another part to this procedure that I was unaware of, or If I was somehow in the wrong area. I'm trying to find out now because I only have a very limited amount of time with the car.
Can anyone help me out?
Ps, He is specifically looking to change the desired idle speed setting in the ecm, doesn't want to adjust the screw or drill a hole in the Tb
edit:
forgot to mention, its a trex cam, but I don't know the specs. The pcm was already tuned for the cam, but the idle speed is still a tad too, and occasionally will stall.
Last edited by j498; 08-28-2008 at 08:42 PM.
08-28-2008, 08:50 PM
#2
You cannot do it with a TECHII. Simple as that. What you want to do is considered editing, and you cannot edit with a TECHII. Period.
Only thing you can do with a TECHII is upload GM specific files, tunes, updates, whatever you want to call them.
Raising of the idle can be done using the bi-di controls in the scanner function, but it does not burn it to the memory.
Drilling a hole in the T-body does you no good, because without raising the idle in the tune, the IAC will just close up more, trying to get the idle back down to the desired speed.
Only thing you can do with a TECHII is upload GM specific files, tunes, updates, whatever you want to call them.
Raising of the idle can be done using the bi-di controls in the scanner function, but it does not burn it to the memory.
Drilling a hole in the T-body does you no good, because without raising the idle in the tune, the IAC will just close up more, trying to get the idle back down to the desired speed.
08-28-2008, 09:58 PM
#3
I see, I was wondering why I was able to only temporary change with the tech 2 hooked up. I thought I was in the wrong area or was doing something wrong.
I could of sworn I changed my tire size with the tech2 before?
From what i read in the service manual I figured the ecm would do something like that with the IAC (close it to compensate for a high idle from a moded tb plate), that's why I wanted to attempt this.
I was reading in some bulletin that there is a "highe idle" parameter in some of the newer software but this is a tech 2 with the older 10mb pcmcia card, I dont have the 32mb card.
I assume the same is true for changing the rear gear ratio?
I could of sworn I changed my tire size with the tech2 before?
From what i read in the service manual I figured the ecm would do something like that with the IAC (close it to compensate for a high idle from a moded tb plate), that's why I wanted to attempt this.
I was reading in some bulletin that there is a "highe idle" parameter in some of the newer software but this is a tech 2 with the older 10mb pcmcia card, I dont have the 32mb card.
I assume the same is true for changing the rear gear ratio?
08-28-2008, 10:26 PM
#4
You can change gear ratios by changing RPOs. Totally different thing. Thats still not editing. It's changing what the computer thinks the car came with from the factory.
You cannot tell the computer the car has a 4.56. You cannot change the idle.
To correctly change the idle, you need to increase the base idle airflow, as well as the idle speed. You need to purchase a tuner suite. HPtuners or EFIlive.
You cannot tell the computer the car has a 4.56. You cannot change the idle.
To correctly change the idle, you need to increase the base idle airflow, as well as the idle speed. You need to purchase a tuner suite. HPtuners or EFIlive.
08-28-2008, 10:37 PM
#5
I see, that's logical.
For future reference, where/how buried are the RPO settings for the gear ratio?
I don't remember seeing it anywhere(although I wasn't looking at the time), that's essentially what I would wanna do. Im not making any drastic changes, being able to change from gu4-gu6 etc would be one of the things I might need to do.
While I'm at it, what about the tires? I could of sworn I changed the tire size from 235. 75r15 to 235 70r15 on my one blazer... and I don't believe it was a false memory either.. lol
For future reference, where/how buried are the RPO settings for the gear ratio?
I don't remember seeing it anywhere(although I wasn't looking at the time), that's essentially what I would wanna do. Im not making any drastic changes, being able to change from gu4-gu6 etc would be one of the things I might need to do.
While I'm at it, what about the tires? I could of sworn I changed the tire size from 235. 75r15 to 235 70r15 on my one blazer... and I don't believe it was a false memory either.. lol
