While puittin the plenum back on - I may have twisted the nuts on the throttle cables - not even sure if I got the right on on the right side.
In parking gear, the car is doing around 11-12 hundred RPM.
In "D" gear the rpm drops to 650-700 rpm.
Are these correct value?
Thanks again
Correct RPM at idle?
Since it is doing about 1K in park (warmed up) - how can I bring it down to the 650+/- 50 RPM?
Can the throttle cables adjusted to lower the RPM? If so - which one - there are 3 of them (one that loops the secondary throttle to the main one and the other two that directly go to the driver side throttle pulleys?
Or is it more involved?
Thanks
Can the throttle cables adjusted to lower the RPM? If so - which one - there are 3 of them (one that loops the secondary throttle to the main one and the other two that directly go to the driver side throttle pulleys?
Or is it more involved?
Thanks
-
Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Make sure there is some slack in the cable at the throttle body [1/8-1/4"] HOT.
When you clean the throttle body, the IAC bypass valve may have been adjusted outwards [in the past] to raise the dirty idle by letting additional air bypass [around the throttle body] into the engine.
Turn the bypass screw inwards till it bottoms then outward 3-3.5 turns this is the correct position IF everything is CLEAN AS NEW!!!!!!!
You really need a Consult to set the idle correctly by setting the IAC to 10-12% extra air [the duty cycle of the solenoid driven by ecu][warm no ac no lights or electrical load]. It will go up to 20-25% in drive and 30-35% when AC on in drive brakes applied.
Important because the IAC acts like the daskpots of OLD, when you get off the throttle it progressively drops the rpms to avoid engine stalls and immediate severe deceleration......the IAC may be 89% at 60 mph cruise AC on [engine 2000 rpm].So if misadjusted to compensate for dirt things on the highway may be strange [loss of dynamic range of cruise control].
Remember the idle speed is controlled by coolant temperature [during the crank warmup phase] so all bets are off until the coolant warms to 176F! 1400 rpm in Park is normal upon crank then for 2-10 minutes it declines down to 750 rpm.In drive the idle should be 650-675 rpm no matter what load is applied IF the IAC has enough range to compensate for load.
DON"T SET THE CABLE STOPS COLD!
About 95% of the Q have idle problems because some tech set the IAC, cable stops, etc wrong to compensate for a dirty intake system instead of requiring a cleaning and the proper rest proceedure.Worse are the idiots that fiddle with the NON FIELD ADJUSTABLE THROTTLE BODY SCREWS/stops.....warm up offsets......it takes hours and days to reset them correctly because one is set at 32F and the other at 176F plus the heated [by coolant] wax expansion device.....................a 1/4 of a turn will cause problems!
The above points out that the system was designed not to be driven or recranked untill warm [short cold start and a 1 minute drive....Street to garage] will give the ecu fits.
Many temperature sensors try to protect things from owners who abuse this proceedure but a 5 minute warm [then at least a 10 minute drive] is the minimum to achieve design life.
When you clean the throttle body, the IAC bypass valve may have been adjusted outwards [in the past] to raise the dirty idle by letting additional air bypass [around the throttle body] into the engine.
Turn the bypass screw inwards till it bottoms then outward 3-3.5 turns this is the correct position IF everything is CLEAN AS NEW!!!!!!!
You really need a Consult to set the idle correctly by setting the IAC to 10-12% extra air [the duty cycle of the solenoid driven by ecu][warm no ac no lights or electrical load]. It will go up to 20-25% in drive and 30-35% when AC on in drive brakes applied.
Important because the IAC acts like the daskpots of OLD, when you get off the throttle it progressively drops the rpms to avoid engine stalls and immediate severe deceleration......the IAC may be 89% at 60 mph cruise AC on [engine 2000 rpm].So if misadjusted to compensate for dirt things on the highway may be strange [loss of dynamic range of cruise control].
Remember the idle speed is controlled by coolant temperature [during the crank warmup phase] so all bets are off until the coolant warms to 176F! 1400 rpm in Park is normal upon crank then for 2-10 minutes it declines down to 750 rpm.In drive the idle should be 650-675 rpm no matter what load is applied IF the IAC has enough range to compensate for load.
DON"T SET THE CABLE STOPS COLD!
About 95% of the Q have idle problems because some tech set the IAC, cable stops, etc wrong to compensate for a dirty intake system instead of requiring a cleaning and the proper rest proceedure.Worse are the idiots that fiddle with the NON FIELD ADJUSTABLE THROTTLE BODY SCREWS/stops.....warm up offsets......it takes hours and days to reset them correctly because one is set at 32F and the other at 176F plus the heated [by coolant] wax expansion device.....................a 1/4 of a turn will cause problems!
The above points out that the system was designed not to be driven or recranked untill warm [short cold start and a 1 minute drive....Street to garage] will give the ecu fits.
Many temperature sensors try to protect things from owners who abuse this proceedure but a 5 minute warm [then at least a 10 minute drive] is the minimum to achieve design life.
Dennis - thanks for the reply. Following your recommendation, I was able to bring down the idle back to 750 rpm (or close abouts)
One thing I think I have messed up during putting the plenum back - is the order of the throttle cables. The throttle pad is not going all the way down when I apply depress the pedal - leads me to believe that I have misplaced the throttle cables on the throttle pulleys.
Can anyone be kind enough to let me know which throttle cable goes where (there are 3 of them). I think I am not sure which cable goes on which pulley on the passenger side end point.
Thanks
One thing I think I have messed up during putting the plenum back - is the order of the throttle cables. The throttle pad is not going all the way down when I apply depress the pedal - leads me to believe that I have misplaced the throttle cables on the throttle pulleys.
Can anyone be kind enough to let me know which throttle cable goes where (there are 3 of them). I think I am not sure which cable goes on which pulley on the passenger side end point.
Thanks