funny idle problem
02-25-04, 07:56 PM
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funny idle problem
ok my car will idle just fine usually, but it seems that when im at stop lights and i press the brake down the car bogs and drops to like 500 rpms and then if i keep on the brakes it will make its way back up to about 700-800. and sometimes when im just crusing around and i press in the clutch the rpms will bounce off 500 and then get back up to 800 or so, (normal idle) also if i have the heat on, or the fan at least that will also bring my idle down, any suggestions on why this could be happening?
02-26-04, 10:39 AM
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all those wires are new, i have a good new ground, cuz i just put in the motor like 6-7 moths ago, ill check it, but i know the cables are new, i have good grounds and powers and the connections should be a grade.
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02-26-04, 10:49 AM
#8
84SE-EGI helpy-helperton
It is perfectly normal for the idle to drop when you apply braking pressure, since you're essentially 'creating' a temporary vacuum leak as the vacuum assist routes intake vacuum to the brake diaphragm. This is what gives power brakes their power.
As the vacuum stabilizes (diaphragm gets expanded in the brake booster), then the volume flow is fixed once again, and the idle should be compensated. This will mean that the idle comes back up again to where it was before you pressed the brake pedal. Then, when you let off the brakes, there is a one-way valve that prevents air flow going back to the intake, so the idle should NOT change.
During high electrical load conditions, such as running headlights, pressing brake lights, stereo, electric fan, etc. - you may notice a drop in idle speed because the alternator has more resistance to generate the current necessary to run these additional accesories, again - perfectly normal.
The only way to reduce this idle drop would be to get a super-sized (current) battery, go with a higher amperage alternator installation (custom), or don't use your brakes. HTH,
As the vacuum stabilizes (diaphragm gets expanded in the brake booster), then the volume flow is fixed once again, and the idle should be compensated. This will mean that the idle comes back up again to where it was before you pressed the brake pedal. Then, when you let off the brakes, there is a one-way valve that prevents air flow going back to the intake, so the idle should NOT change.
During high electrical load conditions, such as running headlights, pressing brake lights, stereo, electric fan, etc. - you may notice a drop in idle speed because the alternator has more resistance to generate the current necessary to run these additional accesories, again - perfectly normal.
The only way to reduce this idle drop would be to get a super-sized (current) battery, go with a higher amperage alternator installation (custom), or don't use your brakes. HTH,
Last edited by LongDuck; 02-26-04 at 10:55 AM.
06-02-04, 01:21 AM
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all I can say is it sux when ur brap brap turns into a brbrrbrbrbrbrbrbrbrbrbrbrbrbrb put brbrbrbr bput coz ur idle drops due to lights being on or stereo, etc. New alternator coming my way 
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