Idle rises steadily to 1500 then falls till it dies??
09-21-2011, 03:09 PM
#1
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Car: 85 chevy k5
Engine: TBI 350 H.O.
Transmission: 700r4
Axle/Gears: 4.10
Idle rises steadily to 1500 then falls till it dies??
just wanted to get peoples thoughts on why it might be doing this...
in open loop, no real issues with idle. the real problem's in closed loop. in gear it idles around the 700 mark failry steady. but throw it in park, it will idle around 1100 for about 30 seconds then start to rise steadily till the 1500 mark, then it will try to bring the idle back down and not catch itself and just falls till it dies. any ideas what could be causing this?
in open loop, no real issues with idle. the real problem's in closed loop. in gear it idles around the 700 mark failry steady. but throw it in park, it will idle around 1100 for about 30 seconds then start to rise steadily till the 1500 mark, then it will try to bring the idle back down and not catch itself and just falls till it dies. any ideas what could be causing this?
09-21-2011, 03:31 PM
#2
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Car: 95 9C1,99 Sierra,90Sierra,00 sierra
Engine: TBI350,LM7,LT1,Vortec 350
Transmission: 700r4,4L60e,4L60e,4L80e
Axle/Gears: 10 bolt,14bolt,3:42,3:73,3:08,3:73.
Re: Idle rises steadily to 1500 then falls till it dies??
tps or iac valve.
09-21-2011, 03:35 PM
#3
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Car: 85 chevy k5
Engine: TBI 350 H.O.
Transmission: 700r4
Axle/Gears: 4.10
10-07-2011, 03:32 PM
#4
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Car: 1989 Firebird
Engine: 5.7 LS1
Transmission: T56
Re: Idle rises steadily to 1500 then falls till it dies??
Probably bad IAC but testing the TPS is easy, could also be the MAP sensor. But with what you are describing if it was me I would replace the IAC and go from there.
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