What causes bouncing RPM?
If your RPM fluctuates while accelerating, it could be because your spark plugs have gone bad on you. Worn-out spark plugs can cause misfires to occur within your engine, and those misfires can lead to your engine vibrating a whole lot. Those vibrations can lead to the RPM in your engine going haywire on you.
How does hard starting work on a Saab 900?
First, the hard starting. To start the car, it would require several cranking sessions of about 5 seconds or longer to turn over. Then, the stalling. Once turned over, the car would idle normally for a few seconds, hanging around the 1K RPM mark. After that, it was start to stagger and begin stalling.
What is the AMM on a Saab 900?
The AMM is the Air Mass Meter, also known as the Air Flow Meter, the unit that snaps on between the air filter and the intake manifold. The fuel for any CIS system is controled by the position of a rod inside the fuel control head.
Is the fuel pump on the bottom of the Saab 900?
For what it’s worth, I did find an ’89 SAAB 900 n/a fuel pump and after checking eeuroparts.com, it appears that’s on the same compatibility list as my 900. It looks like it’s complete, except for possibly a fitting that’s on the bottom of the assembly.
Why does my idle bounce?
An idle surge can be caused by multiple phenomena. The idle air controller is simply a computer-controlled motor that controls idle. There could also be another sensor that is telling the computer to compensate, and in turn, this causes the idle to surge as it looks for the correct RPM level.
Why do cars idle high when Started?
When a cold engine is started, a component called the auxiliary fuel injector sprays additional fuel into the intake manifold. The extra fuel helps the engine start faster. So, the throttle valve opens to raise the engine’s idle speed. That’s why you see the engine idling at 1500rpm or even higher.
Where should my RPM be at idle?
Wrong Idle Speed – Most cars have a proper idle speed, usually between 600 and 1000 RPMs. Idle car speed can change due to wear and tear. Fortunately, an adequate tune-up can restore the correct idle speed.
What causes a car to idle at 1500 rpm?
The idle control circuit is very common to have problems. Pull the ecu and check the board for damage. Vacuum leaks, TPS settings, BISS settings, throttle cable adjustment, stop screw adjustment. All of these have cause idle issues on my car at one point or another.
Why does my car vibrate at 1000 rpm?
Between 1000 & 2000 rpm Shaking or vibration may be caused by many different things such as faulty spark plugs, poor fuel pressure or misfires. Other things such as a faulty idle air control valve may cause the engine idle to drop below the normal idling RPM which may also cause the motor to shake or vibrate more than normal.
Why do the RPMs go up when I accelerate?
Also when I accelerate sometimes the rpms wont go up, they will actually slowly drift down, then when I release the accelerator pedal, they jump up quick then fall back down. I have already changed the ignition coils. The spark plugs have maybe 10000 miles on them, theyre ac delco iridium plugs, it has taylor spiro cables on it.
What causes the tachometer needle to bounce while driving?
The bounce of the tachometer needle happens when speed is constant under little to no torque, anywhere between 30-58 km/h, the RPM ranges 1300-1800-ish {if I press or release the accelerator slightly the RPMs stay steady, and the bouncing tach needle stays steady}.