Cold start problem/surging idle
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Junior Member
Joined: Mar 2006
Posts: 4
Likes: 0
Car: 1988 Firebird
Engine: 5.7 TPI
Cold start problem/surging idle
Facts: 1988 Firebird: 5.7 TPI: Cold start problem.
Help!
<O
Problem: When the vehicle is cold, the car cannot maintain an idle unless I hold the rpms around 1.5 or 2 until the car heats up. Then the idle maintains itself. The idle does hunt and surge sometimes between 500 and 1000 rpms. The car will start up nice and maintain an idle only while the engine is hot! Otherwise, the same game of warming the vehicle up again occurs.
<O
When I unplug the MAF sensor the Firebird starts up great when it is cold. When the vehicle gets hot, the engine does not want to produce power, so I plug the MAF sensor back in and the car runs great.
I have pulled codes and it gave me a low tps voltage code. I checked the wiring harness and it is good.
<O
Replaced: spark plugs, wires, cleaned distributor, submergible fuel pump, fuel filter, TPS (reset to .56V closed throttle), idle air control (cleaned passageways), both temperature sensors (one for the gauge), EGR valve, EGR solenoid, EGR temp. sensor.
<O
I am suspecting a bad MAF sensor. Can anyone confirm this or give me some direction? Could it be a faulty cold start switch used for the brief 8 second operation which operates only during starting? Thanks.
Help!
<O
Problem: When the vehicle is cold, the car cannot maintain an idle unless I hold the rpms around 1.5 or 2 until the car heats up. Then the idle maintains itself. The idle does hunt and surge sometimes between 500 and 1000 rpms. The car will start up nice and maintain an idle only while the engine is hot! Otherwise, the same game of warming the vehicle up again occurs.
<O
When I unplug the MAF sensor the Firebird starts up great when it is cold. When the vehicle gets hot, the engine does not want to produce power, so I plug the MAF sensor back in and the car runs great.
I have pulled codes and it gave me a low tps voltage code. I checked the wiring harness and it is good.
<O
Replaced: spark plugs, wires, cleaned distributor, submergible fuel pump, fuel filter, TPS (reset to .56V closed throttle), idle air control (cleaned passageways), both temperature sensors (one for the gauge), EGR valve, EGR solenoid, EGR temp. sensor.
<O
I am suspecting a bad MAF sensor. Can anyone confirm this or give me some direction? Could it be a faulty cold start switch used for the brief 8 second operation which operates only during starting? Thanks.
Senior Member
iTrader: (4)
Joined: Mar 2006
Posts: 683
Likes: 2
From: Florida
Car: '87 Trans-Am
Engine: LB9 (305 TPI)
Transmission: 700R4
Axle/Gears: 3.42 or 3.73..figuring it out still
Unless it is below 40 degrees, that cold start injector shouldnt even be operating. IS the check engine light still on once you reset your TPS?
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nhra-trans-am
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Sep 17, 2015 10:16 PM
