RPM drops down and jumps up
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RPM drops down and jumps up
My car rpms jump when the car idles and its trippy. Im not sure if this is a major must fix or if its just because of its age. Its a 2000 ls 400 and I have no warranty.
#4
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vacuum leak, engine coolant temperature sensor or ECU capacitors are the most likely
Last edited by LScowboyLS; 07-07-13 at 09:56 AM.
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vacuum leak, engine coolant temperature switch or ECU capacitors are the most likely
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The posted image is somewhat misleading: there are two "engine coolant temperature switches" on these engines, and none are in that image. The two that are there are "Engine coolant temperature SENSOR" and another one with one wire I believe is correctly described as "the coolant temperature gauge sensor" (which is the gauge we see on our display).
I only came upon this posting because I am looking for this elusive "engine coolant temperature switch" of which there should be two, one mounted on the bottom of the radiator, and the other, somewhere else... which all influences the electric cooling fans, which in my case do not work right now, even though they are ok... apparently those switches are not sending a signal to turn on the fans.
Sorry that this does not answer the OP question, but if I had to venture a guess, for a 13 yr old LS, I would first check the ICV and then the caps on the ECM (or ECU - same thing).
I only came upon this posting because I am looking for this elusive "engine coolant temperature switch" of which there should be two, one mounted on the bottom of the radiator, and the other, somewhere else... which all influences the electric cooling fans, which in my case do not work right now, even though they are ok... apparently those switches are not sending a signal to turn on the fans.
Sorry that this does not answer the OP question, but if I had to venture a guess, for a 13 yr old LS, I would first check the ICV and then the caps on the ECM (or ECU - same thing).
#12
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I only came upon this posting because I am looking for this elusive "engine coolant temperature switch" of which there should be two, one mounted on the bottom of the radiator, and the other, somewhere else... which all influences the electric cooling fans, which in my case do not work right now, even though they are ok... apparently those switches are not sending a signal to turn on the fans.
there is also a cooling fan relay that needs to be working right for the fan to come on
this table may be helpful, keep in mind that "A/C switch" in this table refers to pushbutton switch inside car on climate control panel
also, you can test the motor itself easily, hook up in series with an ammeter, directly to battery, motor should come on at the HIGH speed and pull between 4.2 - 4.4 amps
Last edited by LScowboyLS; 07-07-13 at 10:20 AM.
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