help Car stalls
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Joined: Jun 2001
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From: Canada QC.
help Car stalls
Hi I got a 1986 Berlinetta v6 2.8 lt. mpfi
When i start the car every thing is okay it's after 10 min or so that the car idles lower then it starts to miss and stalls.
It's like a cylinder doesnt work and if i give it a lot of gas or not enough it stalls.
I chaged the oil change spark plugs
Need help thanx
When i start the car every thing is okay it's after 10 min or so that the car idles lower then it starts to miss and stalls.
It's like a cylinder doesnt work and if i give it a lot of gas or not enough it stalls.
I chaged the oil change spark plugs
Need help thanx
Moderator
Joined: Jan 2000
Posts: 19,656
Likes: 310
C/B,
Your MPFI still uses an idle air control. Try cleaning the throttle body and IAC air passages with spray carburetor cleaner.
Check the TPS sensor for voltage at the idle position (0.50-0.61 VDC on a V-6 MPFI).
Check the minimum air position adjustment AFTER the IAC and throttle body are cleaned.
Your MPFI still uses an idle air control. Try cleaning the throttle body and IAC air passages with spray carburetor cleaner.
Check the TPS sensor for voltage at the idle position (0.50-0.61 VDC on a V-6 MPFI).
Check the minimum air position adjustment AFTER the IAC and throttle body are cleaned.
Moderator
Joined: Jan 2000
Posts: 19,656
Likes: 310
C/B,
I know it could be that because all EFI engines rely on the Engine Control Module (ECM) to maintain the idle speed based on various inputs from the engine sensors. This is accomplished by a small stepper motor (Idle Air Control motor, or IAC) that regulates the amount of air admitted to the engine, along with the length of the electrical pulses to the fuel injectors to regulate the amount of fuel admitted. The IAC is operated by the ECM based on inputs from coolant temperature, throttle position, and manifold air pressure sensors. For all this to work correctly, the ECM has to presume that the air passages are clean and clear, and the throttle plate must close correctly. For this to happen, the throttle body needs to be clean.
Since all air entering the engine passes through the throttle body, and most idle air passes through the IAC air passages, these areas tend to get dirty over time. It's a common problem, and can be a variable in diagnosing any idle quality issues. It's easy to clean the throttle body and eliminate these variables, and is a general good preventive maintenance procedure.
Aside from that, I'm just guessing....
I know it could be that because all EFI engines rely on the Engine Control Module (ECM) to maintain the idle speed based on various inputs from the engine sensors. This is accomplished by a small stepper motor (Idle Air Control motor, or IAC) that regulates the amount of air admitted to the engine, along with the length of the electrical pulses to the fuel injectors to regulate the amount of fuel admitted. The IAC is operated by the ECM based on inputs from coolant temperature, throttle position, and manifold air pressure sensors. For all this to work correctly, the ECM has to presume that the air passages are clean and clear, and the throttle plate must close correctly. For this to happen, the throttle body needs to be clean.
Since all air entering the engine passes through the throttle body, and most idle air passes through the IAC air passages, these areas tend to get dirty over time. It's a common problem, and can be a variable in diagnosing any idle quality issues. It's easy to clean the throttle body and eliminate these variables, and is a general good preventive maintenance procedure.
Aside from that, I'm just guessing....
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