RAINBOW

Car is running great since sending the ECU off to ATE in Tenn.(1500 miles since the fix) It ended all of the starting, running,and idling problems. Only two things left that bug me. Trans mount (fixing this weekend) and high idle with the A/C on and in gear.Take it out of D into N and it idles around 700rpm.Put it back into D and it jumps up to about 800/850 rpm enough to have to firmly hold the brake (it's always done this) Engine idles 600/650 without A/C. Question: Is this totally ECU controlled, or is there a way to set the A/C idle step-up ?

seanriley

Im having the same exact problem in my Sc400 and would like to also c what the problem was??

thomashill

91 ls400, 238000 mi, high idle on & off a/c, had dealer top problem solver work on it for 5 days with no results (no charge too), w/a/c off it will idle down, but while i am breaking the idle is arround 1000rpm. TPS is new and not the problem.

vaughn37

your engine idle in neutral without a/c should be around 650rpm.....with a/c neutral 900rpm

my rpm at idle in drive with out a/c is about 240rpm.

Iam no expert but it sounds to me like a transmission problem maybe torque converter? or a sensor/solenoid?

keep in mind the power steering pump also has a idle up device... good luck finding your problems

vaughn37

maybe someone else can chime in on my post above....I am taking my info from the manual.But 650 rpm seems high while in neutral....when i shift to drive it drops to around 240 but it sounds like it is hard on the transmission ......so today i lowered my idle control.now im reading about 200 rpm in neutral and drive.maybe my rpm gauge isnt reading correctly?