What causes an engine surge when the ECU is off?
If closed TPS voltage changes, the ECU may assume that your foot is on the throttle, causing a richer fuel mixture to be delivered. This can also be caused by a faulty TPS, or even a poor ground. With the engine off, check TPS voltage with the accelerator pedal relaxed. Then work the pedal a few times and see if the voltage changes.
What does full operation mean on the O2 sensor?
5) Full operation means the engine is fully warmed up, O2 sensor above the 600 deg. F. operating temperature, and no fuel or mechanical problems present. 6) The O2 sensor must cycle at least once per second, which would show 3 cross counts on the scan tool PID. 7) Silicone is the leading cause of O2 contamination.
What does 0.450 volts mean on an O2 sensor?
After an engine has ran through its warm up period (O2 sensor has no effect on engine operation while the engine is cold), the ECM then looks for the O2 value. The 0.450 volts mark is considered almost universally as the midway point or crossover point for O2 sensor operation.
What causes an engine surge during fuel injection?
In combination with the camshaft position sensor (CMP), the CKP signals are used by the ECU to manage fuel injection and spark delivery. A faulty CKP (or CKP circuit) can easily cause an intermittent misfire, which naturally results in what the driver may perceive as a surging effect.
When does an O2 sensor cause a surge?
Normally, your computer will throw a check-engine light and an O2 sensor failure code when the sensor gets bad enough to surge. But this isn’t always the case; sometimes, the O2 sensor can trick the computer into thinking that everything’s fine. One quick way to diagnose O2 sensor surge is to unplug the O2 sensor’s wiring harness.
What should O2 reading be for idle surge?
Use pin 29 (left O2) or pin 43 (right O2) and the ground next to the computer ground. The individual O2 sensor should read between 0.20 to 0.90v at idle. The computer will throw codes 41 and/or 91 for possible O2 sensor failures.
Why does an O2 sensor slow down the computer?
But that loss of efficiency in the O2 sensor slows the sensor’s response time, so that it responds to changes in oxygen content in tenths of a second instead of thousandths of a second. Your computer very rarely settles on a set amount of air and fuel; it’s always making minor adjustments to the ratio using information from the O2 sensor.
Where is the O2 oxygen sensor in the engine?
Also, The (O2) Oxygen Sensor is not able to measure the air or the fuel entering the engine. Because, the (O2) Oxygen Sensor is located in the exhaust and that where it reads the actual oxygen content in the exhaust. Depending on the year; make and model of your vehicle you could have anywhere from one to four (O2) Oxygen Sensors.
What causes idle surges on a car ECM?
Idle surging can be caused due to other issues in the car, but if it happens in conjunction with other throttle position sensor symptoms, the culprit is often the TPS. At idle, the ECM will not get the correct information and the throttle will variate randomly causing idle surges.
What are the signs of a failing ECM?
Common signs of a failing PCM/ECM/ECU include the Check Engine Light coming on, engine performance issues, and the car not starting. 1. Check Engine Light Turns On 2. Engine Stalling or Misfiring 3. Engine Performance Issues 4. Car Not Starting
What are the signs of a failing ECU?
Common signs of a failing PCM/ECM/ECU include the Check Engine Light coming on, engine performance issues, and the car not starting. 1. Check Engine Light Turns On
What should I do if my Mercedes Benz won’t start?
Start the car and you should be able to get around 60 psi. When the engine is running and when you turn off the engine the pressure should stay steady. Always perform this test on a cold engine. Next, make sure that the fuel injector connections are secure and not loose. Check the fuel pump and the fuel pump relay.
Why does my Mercedes Benz make a clicking noise?
It requires electrical power to crank the engine. The car makes a clicking noise but won’t start. Hint: Starter Problem or Low Battery This may seem obvious, but an old battery is the root of many headaches and can cause all sorts of malfunctions on Mercedes-Benz cars.
What are the problems with a Mercedes Benz?
Top 5 Mercedes-Benz no start problems 1 Engine Click, No Start 2 Engine Dies Right After It Starts 3 Car turns over, but it won’t start 4 The car makes a clicking noise but won’t start. Hint: Starter Problem or Low Battery 5 Key will not turn the ignition More
Why is my Mercedes Benz gear shift stuck?
Gear shift stuck is one of the most common problems with Mercedes-Benz cars. Unfortunately, looking to see if the brake lights turns on while you press the brake pad, is not a good test to tell if the brake light switch is working properly.
If closed TPS voltage changes, the ECU may assume that your foot is on the throttle, causing a richer fuel mixture to be delivered. This can also be caused by a faulty TPS, or even a poor ground. With the engine off, check TPS voltage with the accelerator pedal relaxed. Then work the pedal a few times and see if the voltage changes.
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.
When does motor surging occur on a ski?
The surging makes it very difficult for them when they ski with their foot in the rope. No problem pulling two of them up, accelerates smoothly. We usually run at 25 mph when skiing. That’s when the surging occurs. Going to try changing spark plugs.
Why does my Sea Doo have a surging problem?
However, it does have a surging problem when I move the throttle just off of idle (the motor will constantly surge between 1,800rpm and 2,400rpm). If I keep increasing the throttle the surging will stop at 2,500rpm and run smooth again.
Is the 300ZX a good car to drive?
What a wonderful opportunity to take the old 300ZX out for a spin. T-tops off, sunglasses on, music locked in, and turbos spooling as you blast down the highway. The car is a mechanical beast in harmony with nature, and you’re present to orchestrate it all. “Life is good!”, you think.
How does a bad ECM affect fuel economy?
Poor Fuel Economy. A faulty ECM disallows your engine from knowing how much fuel to burn in the combustion process. Typically, the vehicle consumes more fuel than it should in this situation. You’ll end up paying more for gas than you would with a functioning ECM. The ECM plays a vital role in engine performance.
How to check the ECU on a Nissan 300ZX?
Connect the Consult cable to the Consult Port on your car, and plug it into your computer. c. Turn the key to “ON” (you can start the car if you want, but there’s really no point). d. Launch the program. e. Click “Self-Diagnostics.” f. The program will check the ECU for codes and display them and their meaning.
What’s the diagnostic mode on a Nissan 300ZX?
On the ECU itself is a red LED diagnostics mode light. Next to it is a small dial with a slot called a potentiometer. The dial has two positions: Mode I and Mode II. Mode I (all the way counter-clockwise) is normal operation. Mode II is diagnostics mode.
How to turn the potentiometer on a Nissan 300ZX?
Using a paperclip, or small wire, jump the connection between pins 8 and 9 on the Consult connector, as shown below: c. Hold the jump for three seconds, then remove the jump. This is essentially the same as turning the potentiometer on the ECU.
What does code 34 read on Nissan 300ZX?
For example, Code 34 (Detonation Sensor Circuit) would read like this: If you’re reading off the CEL, it would blink the same way. 54: Signal Circuit from A/T to Transmission Controller Unit. 55: No malfunction.