I have a problem with my rpms. I have a 99si w/ a 99gsr motor that runs great. however sometimes when I down shift and reduce my speed to come to a stop my car tends to drop the rpms way below 500. I set the rpms around 900 and they either go up to 1500 when I stop at a light or drop too low when I down shift and come to a stop. In a few occations shutting off completely due to the low rpms.
My brother said it could be a sensor, or vaccum line... any suggestions?
I used my si harness with it and I remember having an extra plug on the gsr harness that I thought was for the secondary butterfly that I dont need. correct?
The secondary butterfly has a line hooked up to it that comes from the back of the motor. could that be the problem? should I unplug it?
I'm not a mechanic so please give me names of the sensors or whatever... thanks for the help!


Modified by denali99si at 12:58 PM 11/14/2006


Modified by denali99si at 6:17 AM 11/15/2006


Modified by denali99si at 6:18 AM 11/15/2006

 

You should run the correct ECU for the motor, GSR fuel and timing maps are different from b16.

Also could be IACV (idle air control valve), does it stall only when you stop and does the bouncing idle go away sometimes or is it always there.

You shouldn't have any open vaccum lines so if you see one, at the very least you should plug it, see if it solves the problem. If so then find out where to run it.

 

I'm using a b16 computer. The car doesn't stall at all when running or park.
The rpms only drop when I go fast and come to a complete stop, but only if I press the clutch all the way in before stopping. If I down shift my way to a complete stop the rpms dont drop at all but if I throw it into 2nd and leave the clutch down while the car is still moving the rpms shoot down.
When I'm at a light ready to take off they always go up to 1500. I noticed that when I easy off the clutch a little bit right before taking off the rpms go back down to 900 so I usually do that to control the rpms from going up. Basically the problem gets solve by pressing or easing off the clutch.
Thanks for ur help MotorMouth!


Modified by denali99si at 6:27 AM 11/15/2006

 

I think I found my problem...
There's 2 sensors on top of the intake manifold, one in the middle of it and one off to the left. What's the one off to the left for? I dont have a plug for it. Now that's definetly a problem!

 

I still need help!
I talked to a friend and he said that the other smaller plug on the intake manifold that's not plugeed in is for the secondary butterfly, and that I don't need it. I checked the vaccum lines and the one that goes to the secondary butterfly was not working. So I T-fitted the line from the fuel pressure regulator and it works now. It looks like the problem w/ the rpms going up stopped but as I took it for a test drive and pulled around the courner the rpms dropped shutting off on me again.
Any other suggestions?