What should the upshift point be on an automatic transmission?
For quick shifting, the upshift points should be close to the maximum RPM of the engine. In this example, that is 2100 RPM. The downshift point is also raised, but cannot be higher than RPM after shifting. It is possible for an automatic transmission to cycle between gears in certain situations.
What should the shift point be at idle?
Shift up below the maximum RPM. Shift down above the idle RPM. The up and downshift points must be far enough apart that the new RPM after shifting up is not lower than the downshift point (and vice versa). The first two rules are fairly obvious.
What causes a car to shift to the up shift point?
Once in the lower gear, the vehicle might have enough torque to accelerate to the up-shift point, causing the transmission to shift back into the higher gear again. This is normal behavior and there is no way to completely avoid it in a vehicle that shifts automatically.
When to set DTC for engine surge maintenance?
• After driving at 6.25 mph or more, the actual engine idling speed varies from the target idling speed by between 100 and 200 rpm, five times or more during a drive cycle. • If the actual idling speed varies from the target idling speed by more than 200 rpm five times or more during a drive cycle, the ECM illuminates the MIL and sets the DTC.
Why is my engine surging at low rpm?
The fuel pressure regulator may be operating at, low pressure. Check fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. Your ignition timing may be set incorrectly. Check and adjust, ignition timing. Ignition system problem causing a, weak spark.
What causes an engine to surge during a tune up?
Step 2 – An engine’s tune up is a regularly scheduled service, when this service is neglected it can cause the engine to surge. Learn more Step 3 – If a fuel pump or regulator is failing is can cause an unsteady volume or pressure for the fuel system causing the engine to surge. Learn more
• After driving at 6.25 mph or more, the actual engine idling speed varies from the target idling speed by between 100 and 200 rpm, five times or more during a drive cycle. • If the actual idling speed varies from the target idling speed by more than 200 rpm five times or more during a drive cycle, the ECM illuminates the MIL and sets the DTC.
What happens if your engine surging or misfiring?
Engine surging, can affect drivability but; can also cause error codes to appear in your, OBD-II system. Furthermore, these codes can cause you to fail your local vehicle inspection; or at the very least can result in that very annoying, Check Engine Light coming on.