Why is my intake camshaft lobe worn on my Corvette?

If an intake camshaft lobe is worn it will not allow fuel and air to be drawn into the cylinder, which will make the engine have a steady miss. From 1972-1981 worn camshaft lobes were a frequent occurrence on small block Chevrolet engines.

What causes a steady miss at idle and under load?

If you have an unexplained miss at idle and under load there are two possible causes that can be difficult to find in some situations. A worn camshaft will cause a steady miss. A slightly worn camshaft lobe will possibly have only a minor tapping noise occur.

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.

Are there any problems with the first Corvette?

The first Corvette experience nagging problems: doors that wouldn’t stay shut, water leaks, and shoddy workmanship of the otherwise innovative fiberglass body. These issues negatively impacted customer impressions caused sales to plummet.

Why does my Corvette have a misfiring engine?

That’s because a misfiring engine can be caused by many mechanical problems. One way to detect a misfiring engine is by sensing the Corvette’s engine stumbling momentarily before regaining power. The engine can jerk or run rough as a result. This happens because the engine has skipped a process in the combustion cycle.

When does the idle air control valve change?

When the engine is running but the vehicle is not moving, this means the engine is idling. During this time, the number of revolutions per minute (RPM) inside the engine will change. The idle air control valve is responsible for managing the engine idle speed.

What happens to your car when you idle?

A rough idle will result in intense vibrations forming whenever your vehicle is stopped with the engine running. Since less air will be going into the engine during its idle state, the car will react by shaking profusely.

What causes the idle speed to randomly fluctuate?

It will cause the idle speed to randomly fluctuate to different speeds rather than stay at one constant speed. The idle speed may be too high at one moment and then too low at other moments.

Why is the EGR not working on my 1975 Corvette?

If you have a 1975-1981 car the EGR valve is most likely not functioning. The 1975-1981 cars had the EGR system removed or plugged because they caused hesitation and stalling. When EGR systems are disabled, the exhaust passages have a tendency to build up carbon, blocking EGR flow. If the EGR valve is stuck open the engine will not idle.

What should the pressure be on a C3 Corvette?

Sometimes a torch is required to heat the A.I.R. check valve during removal. An adapter can be put together to connect the vacuum gauge to the A.I.R. tube. Three pounds of exhaust system pressure is acceptable. Any pressure greater than three pounds indicates a clogged exhaust system.

How to troubleshoot an automotive engine high idle?

The troubleshooting procedure for high and low idle conditions are similar, which are included in the following: Step 1 – If the check engine or service engine light soon has illuminated retrieving the diagnostic trouble codes could lead you in the right direction of what the problem is, or is related too.

How can I keep my car at idle?

Step 3 – Engine vacuum is a sealed system and must hold a specific amount to maintain proper idle conditions, inspect the engine vacuum hoses and intake gaskets. Step 4 – The air intake boot or tube is used to deliver air to the intake system of the engine.

How can I check the idle air control?

To perform a rough check of the idle air control, remove the valve while reconnecting the wiring harness. While observing the valve with a flashlight, turn the key to the “ON” position, (DO NOT START ENGINE.) the valve should move slightly.

When to remove an idle air control valve?

Because of the nature of this valve (large air volume processed) it should be serviced when a tune up is performed to remove “coking” which will hinder the valve’s performance. To perform a rough check of the idle air control, remove the valve while reconnecting the wiring harness.

Why is the PCV valve important in a corvette?

PCV (Positive Crankcase Ventilation) valves are very important for proper engine performance. The PCV valve allows a pressure drop (vacuum) in the engine’s crankcase; this helps piston rings seal. The engine oil stays cleaner because moisture and oil vapors are burned off.

Why is the Corvette fuel tank higher than the carburetor?

The Corvette fuel tank is slightly higher than the carburetor to allow fuel to be gravity-fed to the carburetor. The fuel tank position will allow idling and low speed performance even with a failed fuel pump.

What causes a compression test on a C3 Corvette?

If you have lifter that starts to tap and you adjust it and it requires adjustment again and again, this usually indicates that the camshaft lobe is wearing away. A compression test will show a slightly lower than normal reading if the intake camshaft lobe is worn badly. A broken valve spring can cause a steady miss also.

How is cylinder pressure tested on a corvette?

Cylinder pressure testing is accomplished with a supply of compressed air. First the valve cover should be removed and the valve adjustment backed off on the cylinder being tested. Now compressed air is introduced into the cylinder with an air-hold.

What kind of oil does a 1982 corvette use?

1982 Corvette Specs Oil Pump Type: Gear Crankcase Oil Capacity 4.0 Quarts, Less Filter Recommended Oil Grade Above 20°F: SAE 20W-20, SAE 10W-30, 10W- Fuel Filter Mesh Strainer in Gasoline Tank and Paper

What causes intermittent stalling in a car engine?

More Causes. One of the more unusual causes of intermittent stalling we’ve heard about is a defective vehicle speed sensor. When the vehicle stops moving, the PCM may not engage the idle speed motor (carbureted engines) or idle air bypass motor (fuel injected engines) so the engine will idle normally.

Why does my PCM stall when I Turn on the engine?

The MAP sensor senses intake vacuum, which the PCM uses to estimate load so it can adjust the air/fuel mixture accordingly. If the MAP sensor isn’t reading right, the PCM will receive bad information and possibly add or subtract more fuel than it should causing the engine to stall.

Why does the engine stall when the a / C is on?

Normally, the PCM should increase the idle speed to compensate for the added load on the engine when the A/C is on. But if the A/C signal fails to reach the PCM because of a communications glitch between the A/C module and PCM, the PCM may fail to increase idle speed causing the engine to lug or stall.

What causes an engine to stall at idle?

If the ISC valve is gummed up with fuel varnish or dirt, it may stick, preventing the engine from maintaining the proper idle speed when the throttle closes. A faulty idle speed control circuit may also allow the engine to stall when idling if it fails to compensate for idle loads placed on the engine by the charging system or A/C compressor.

Why does my car stall at low rpm?

The will likely force your computer to stall the engine and only allow it to run at low RPMs, which means the car will only move at slow speeds. This is a safety feature enforced by the computer so that your engine doesn’t get too damaged.

What is the diagnostic code for engine stall?

Diagnostic trouble codes P0120, P0121, P0122, P0123, and P0124 are what will commonly appear. The engine can stall for no reason and without any warning. This happens when the TPS gives incorrect information to the ECM. The engine can stall at high speed, at low speed, or even at idle.

Why is my intake camshaft lobe worn on my Corvette?