I adjusted the tps to where its supposed to be. between .98 to 1 volt. The problem with that is i doubt the meter is that accurate. That is a pretty tight window. I've heard people talking about the computer needs to re-adjust itself and it takes time. If so how much time? The idle is about 1200 but the hanging rpms is what really sucks. any suggestions?
new throttle body-high idle,and hanging rpm's
- Thread starter swl987
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Unhooking the battery does not effect the tune, it only erases the KAM (Keep Alive Memory) which is basically a set of baseline values for sensors emissions controls etc.
Assuming nothing is sticking, double check this real good, it could be anything.
The TPS does not have to be adjusted although it's happy at .98v so leave it there.
If you read the thread I posted, my car never settled down so I returned the unit.
You may need a tune to fix it or it may fix itself after a week or so of driving.
thanks alot for the link. That shop manual said to learn the longer values you have to have the brake on, but it does not indicate exactly how long that could actually be. Accufab said to measure the voltage you should pierce the wire insulation with a small safety pin and put your leads on them. I wonder if i'm getting some noise now on the signal. what a pain in the ash. I figured this would be some nice pain free extra HP. Now my car runs like crap.
TPS voltage didnt matter to me, mine was hanging really bad when i se the idle to 800 rpm with the IAC dissconnected. I read a post from Randy Stinchcomb stating that with the iac disconnected the car should just die or barely run ( ~550 rpm for me)
I ignored TPS voltage and set the trottle body lower and lower till the car just stumbled and died. since then the car is idleing perfect again.
Essentially, with a higher un assisted idle ( from the IAC valve) the car acts like it has a vaccum leak.
I ignored TPS voltage and set the trottle body lower and lower till the car just stumbled and died. since then the car is idleing perfect again.
Essentially, with a higher un assisted idle ( from the IAC valve) the car acts like it has a vaccum leak.
So are you saying I should turn the idle screw down or disconnecting the iac will fix it. I'm kinda slow help me out here. Tim from MPH told me to back the idle screw all the way out. I would assume that is the screw on the top left that acts like the stop for the linkage.right? I tried that and it did'nt work.I backed the screw out a couple threads and there was a gap between the screw and linkage. It really won't let me turn the idle down from there. Accufab's website says you only adjust the idle with the tps. I'm confused.
Don 95Vert
Founding Member
Since idle is a 'learned' function, that answer is partially correct - you need to clear the KAM -a nd messing with the stop screw throws the TPS off - normally the TPS value is reset in the PCM at key-on, but if it is off by too much, you need to readjust it to 0.9-0.99. Here is the procedure we give out to customers who get chips from us...
You probably will need a helper for this procedure.
1)With the motor running unplug the idle air control valve (IAC).
2)The motor may stall or flare at this point.
3)If it stalls, start it again still with the IAC unplugged – have a helper keep the revs up – if it flares go to the next step.
4)Using the throttle stop screw, adjust the idle to where it was commanded – if you do not know, then just pick 800-850 – most tunes are 850. It should idle OK like that.
5)Shut the motor off and disconnect the negative battery cable and step on the brake 3-4 times. Turn the headlight switch on – this drains any excess voltage. Wait 5 minutes or so.
6)Reconnect the battery, plug in the IAC again and start the motor. Should idle better.
7)Shut it off and re-check the TPS voltage. Try to get it back to under 1.0. If it’s too far out of whack, you may have adjusted the throttle stop screw too much. Or if you did not, you have a throttle body that’s a mess. In that case try to come to a happy medium of throttle body stop screw to TPS setting.
8)Sometimes with a BIG cam drilling a small hole in the throttle blade will help get things right, but you do this at your own risk as you can REALLY mess things up if this wasn’t the problem or you made too big a hole.
Be SURE there are no vacuum leaks if it will not hold idle – do a smoke test if necessary.
You probably will need a helper for this procedure.
1)With the motor running unplug the idle air control valve (IAC).
2)The motor may stall or flare at this point.
3)If it stalls, start it again still with the IAC unplugged – have a helper keep the revs up – if it flares go to the next step.
4)Using the throttle stop screw, adjust the idle to where it was commanded – if you do not know, then just pick 800-850 – most tunes are 850. It should idle OK like that.
5)Shut the motor off and disconnect the negative battery cable and step on the brake 3-4 times. Turn the headlight switch on – this drains any excess voltage. Wait 5 minutes or so.
6)Reconnect the battery, plug in the IAC again and start the motor. Should idle better.
7)Shut it off and re-check the TPS voltage. Try to get it back to under 1.0. If it’s too far out of whack, you may have adjusted the throttle stop screw too much. Or if you did not, you have a throttle body that’s a mess. In that case try to come to a happy medium of throttle body stop screw to TPS setting.
8)Sometimes with a BIG cam drilling a small hole in the throttle blade will help get things right, but you do this at your own risk as you can REALLY mess things up if this wasn’t the problem or you made too big a hole.
Be SURE there are no vacuum leaks if it will not hold idle – do a smoke test if necessary.
I tried this method and it did'nt work. I did not re-check the tps voltage because I had to go back to work But I did have it set to .99 before I started. I will check the voltage again tomorrow. Any other suggestions?
Well I tried all of the suggestions and it's a little better but still not right. I got it to idle at 1000 rpm now which is better. Also when I'm driving and I push in the clutch it jumps to 1300 rpm and holds for a couple of seconds. I will keep messing with it until I get it or I rip the throttle body off and smash it. I noticed when I first put my blower on and loaded the tune it had a bit of a high idle and then it just eventually came down. So maybe that will happen again. Thanks for the help and please chime in if you have any more ideas.
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