What causes...
04-09-2003, 01:37 PM
#1
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What causes...
...the RPM to drop on the auto trannies when you shift from Park to Drive? Is it the IAC or some other sensor? Just checking, as m,y car will idle at 1100 rpm in Park but when I shift to Drive or Reverse, the rpm's drop to about 300 and bounce around for a coupke od seconds and then setlle in at about 900rpm. I don't want to through money at a new IAC if it is not the cause. It also has a somewhat erratic idle, but only around 50-100 rpm when settled in. Any idea? Thanks,
Kyle
Kyle
Thanks,
04-09-2003, 06:51 PM
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Originally posted by scoobysnax83
I'm stumped at the simple fact that you can get your car to idle at 50-100rpm.
I'm stumped at the simple fact that you can get your car to idle at 50-100rpm.
Kyle
I get it.....
04-10-2003, 04:50 AM
#7
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So you have an auto and your idle in park is 1100? I think it should be more like 950 and 750-800 in gear someone correct me if I'm mistaken. you MIGHT have an air leak somewhere or did you have your PCM flashed? With my Lunati cam and manual my idle did not change its still at 850-900rpm's. the sudden drop in rpm's can be contributed to a vacuum leak.
04-10-2003, 10:20 AM
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Originally posted by grygst76
So you have an auto and your idle in park is 1100? I think it should be more like 950 and 750-800 in gear someone correct me if I'm mistaken. you MIGHT have an air leak somewhere or did you have your PCM flashed? With my Lunati cam and manual my idle did not change its still at 850-900rpm's. the sudden drop in rpm's can be contributed to a vacuum leak.
So you have an auto and your idle in park is 1100? I think it should be more like 950 and 750-800 in gear someone correct me if I'm mistaken. you MIGHT have an air leak somewhere or did you have your PCM flashed? With my Lunati cam and manual my idle did not change its still at 850-900rpm's. the sudden drop in rpm's can be contributed to a vacuum leak.
Kyle
04-10-2003, 12:37 PM
#11
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Originally posted by vodoo-chile
When I originally flashed the PCM with the new cam/heads program, it did idle at stock rpms. The reason I had the rpm's raised was due to the drop in rpm's when I shifted from park to drive. The car would almost die. I would rather have it idle at stock rpm's and fix the drop. That is why I am asking what causes the rpm to drop when shifted. Thanks,
Kyle
When I originally flashed the PCM with the new cam/heads program, it did idle at stock rpms. The reason I had the rpm's raised was due to the drop in rpm's when I shifted from park to drive. The car would almost die. I would rather have it idle at stock rpm's and fix the drop. That is why I am asking what causes the rpm to drop when shifted. Thanks,
Kyle
04-10-2003, 02:39 PM
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Originally posted by grygst76
Like I said do a check around your engine bay and listen for any whistling or check your intake gaskets, TB gasket,.. If it used to idle perfect and then acted stupid, you could have had something either come loose or the heat cycle created an air leak. check your bolts and make sure every one of them is tight.
Like I said do a check around your engine bay and listen for any whistling or check your intake gaskets, TB gasket,.. If it used to idle perfect and then acted stupid, you could have had something either come loose or the heat cycle created an air leak. check your bolts and make sure every one of them is tight.
Kyle
04-10-2003, 03:10 PM
#13
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To answer your question, the idle speeds are programmed into the PCM, as you have already noted. With the A4, there is a place to program one value for "in neutral" (650rpm stock) and another place to program a value for "in gear" (550rpm stock). It is supposed to drop 100rpm when you put it in gear, at least with stock programming.
The "IAC" is not a sensor... it is an "actuator"... its the valve that opens and closes to set idle speed.
The "IAC" is not a sensor... it is an "actuator"... its the valve that opens and closes to set idle speed.
04-10-2003, 08:35 PM
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Originally posted by Injuneer
To answer your question, the idle speeds are programmed into the PCM, as you have already noted. With the A4, there is a place to program one value for "in neutral" (650rpm stock) and another place to program a value for "in gear" (550rpm stock). It is supposed to drop 100rpm when you put it in gear, at least with stock programming.
The "IAC" is not a sensor... it is an "actuator"... its the valve that opens and closes to set idle speed.
To answer your question, the idle speeds are programmed into the PCM, as you have already noted. With the A4, there is a place to program one value for "in neutral" (650rpm stock) and another place to program a value for "in gear" (550rpm stock). It is supposed to drop 100rpm when you put it in gear, at least with stock programming.
The "IAC" is not a sensor... it is an "actuator"... its the valve that opens and closes to set idle speed.
Kyle