The 4.3 TBI (Throttle Body Injection) system uses a computer to control the amount of fuel that is injected into the engine. The timing of the injection is controlled by the computer and can be adjusted to match the needs of the engine. The timing can be set to meet the requirements of different types of driving, such as stop-and-go city traffic or high-speed highway driving.
- Open the hood of your vehicle and locate the four bolts that hold the timing cover in place
- Remove the bolts with a ratchet and pull the timing cover off to expose the timing belt
- Locate the crankshaft pulley and align the TDC mark on the pulley with the pointer on the timing cover
- Rotate the distributor clockwise until it reaches its correct position according to your engine’s firing order
- Insert a dowel pin into hole in distributor shaft to hold it in place while you install the rotor and cap back on
- Reconnect all of your vehicle’s electrical components, close up the hood and start up your engine to check that everything is working properly
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How Do I Know If My Ignition Timing is Correct?
If your engine is running too slowly, it may be because the ignition timing is set too far retarded. You can check this by disconnecting the vacuum advance hose from the distributor and starting the engine. The engine should idle at about 700-900 RPM.
If it doesn’t, adjust the timing by turning the distributor until you achieve this RPM range.
Once you have the correct RPM, reconnect the vacuum advance hose and drive the car around for a bit to see how it feels. If the car seems to lack power or stalls easily, your timing may be too advanced.
Conversely, if your engine pings or knocks under load, it may be because your timing is set too far advanced.
How Do You Set the Correct Timing?
There are a few things you need to take into account when setting the timing on your car. The first is the type of engine you have. If you have a standard engine, the timing should be set at 8 BTDC (Before Top Dead Center).
If you have a performance engine, the timing should be set at 12 BTDC. The second thing to consider is what octane fuel you’re using. If you’re using 87 octane fuel, the timing should be set at 8 BTDC.
If you’re using 93 octane fuel, the timing should be set at 10 BTDC. Finally, if you live in a cold climate, it’s recommended that you set the timing at 4 BTDC to help prevent pre-ignition and knocking.
How Do I Set the Timing on My Electronic Ignition?
Assuming you would like tips on how to set the timing for an electronic ignition:
One method is to use a timing light. This process will require another person to help you.
Have your helper start the engine and hold it at about 1,500 RPMs. Attach the timing light according to the manufacturer’s instructions and aim it at the harmonic balancer. The harmonic balancer is located at the front of the engine and has a pulley that turns with the crankshaft.
There should be a mark on the pulley that lines up with a mark on the engine block when the engine is at top dead center (TDC). When you see this alignment, note what position the distributor rotor is pointing in. This is your starting point.
Now, have your helper slowly increase the RPMs while you watch the timing marks through the little window in the housing where you attached the lead from the timing light. As long as everything looks good and steady, don’t make any adjustments yet. If things start moving too quickly or erratically, it means something isn’t right and you should shut offthe engine immediately to avoid damaging anything.
What is the Correct Ignition Timing for a Chevy 350?
The correct ignition timing setting for a Chevy 350 engine is 10 degrees BTDC (Before Top Dead Center). This means that when the crankshaft is at the 10 degree mark, the spark plugs will fire. This gives the cylinders enough time to fill with fuel and air before combustion happens.
setting ignition timing on a Chevy TBI 87-93
4.3 Vortec Timing at Idle
If your 4.3 Vortec engine is idling too high, it may be due to the timing being off. To check the timing, you’ll need to use a timing light. First, find the number one cylinder on your engine (it’s usually at the front of the engine on the driver’s side).
Then, attach the red lead of the timing light to the positive terminal of the battery and clip the black lead onto a solid ground. Finally, aim the beam of light at the harmonic balancer and observe where it hits in relation to the TDC mark on the pulley.
If your engine is idling too high, it’s likely that your timing is off by a few degrees.
To fix this, you’ll need to adjust the distributor. Loosen up the distributor hold-down clamp and rotate it slightly until you achieve proper timing. Once you’ve got it set correctly, retighten down the clamp and test drive your vehicle to see if that did indeed fix your problem!
Conclusion
If you own a 4.3 Tbi engine, setting the timing can be tricky. However, it is possible to do it yourself with the right tools and a little bit of know-how. The first thing you need to do is locate the timing marks on the flywheel.
Once you have found them, attach a timing light to the number one spark plug wire and point it at the marks. Next, find the correct position for the distributor on the engine and install it. Make sure that the rotor is pointing at the correct mark on the flywheel before tightening down the distributor clamp.
