Chevy 350 TBI bogs on acceleration due to the following reasons:
- Leaky vacuum lines
- Spark plugs get worn out
- Filter screens get gummed up
- The fuel pump gets defective
- Dirty fuel filter
- Fuel pressure issue
- Defective temp sensor
- A bag fuel pressure regulator
- A faulty ignition system
In this Chevy 350 TBI troubleshooting guide, we will break down each of these problems to let your engine operate smoothly. So, let’s get started right here.
Chevy 350 TBI Bogs On Acceleration [9 Easy Solutions]
This chapter will reveal every culprit that causes your engine to bog on acceleration.
01. Leaky Vacuum Lines
Chevy 350 hesitates on acceleration! Then, our suspicion goes to the vacuum lines or hoses of the car first. Vacuum lines or hoses are the power source of a car. They power up every type of component in your vehicle ranging from the brake booster to the windshield wiper motor and HVAC controls & others.
If these vacuum hoses get leaked or damaged, your vehicle will lose power. In the worst, you can’t even start the engine anymore. Bogs on acceleration, rough idle, and hissing noise coming out of the engine bay are some signs of leaky vacuum lines.
Vacuum hoses are vital for trouble-free component operation. If you notice any of the signs we mentioned above or find any leak, you must replace the vacuum line. To change the vacuum hoses, make sure you have the following accessories at your fingertips:
- Vacuum hose
Now, we recommend you wear safety gloves when working on your vehicle. Open your car hood and locate the vacuum hoses. Then, inspect for cracked or broken vacuum hoses throughout the engine compartment.
Next, pull the leaking vacuum hose from the plastic or metal connectors. Ensure to not damage the connector. Then, push and slide the new vacuum hose onto the plastic connector. Finally, start the engine to check the proper idle speed for verifying your repair.
02. Spark Plugs Get Worn Out
Damaged spark plugs are one of the culprits that cause the engine to bog on acceleration. Overheating (when the cooling system fails to work), carbon buildup, and improper spark plug gap are some reasons responsible for a worn-out spark plug. The following signs will indicate you about a bad spark plug:
- Poor mileage
- Poor acceleration
- Rough idling
- Engine misfire
As soon as you notice those signs when driving, you must replace the spark plug. You should spend $16 to $100 to get a set of spark plugs, depending on the plug type and the number of cylinders your vehicle has.
03. Filter Screens Get Gummed Up
An air filter or screen plays a vital role to keep the engine cool and maximize the engine performance. If your Chevy has a Mass Air Flow sensor, a gummed-up air filter by dirt & debris will reduce the amount of air entering the intake. When you drive with the clogged air filter, 350 TBI hesitation when accelerating is something you will experience.
Cleaning the air filter is an easy solution to the problem. Just open the car hood and ensure the engine bay is cool. Then, locate the air filter and use a screwdriver to remove it.
Afterward, shake the air screen a bit to loosen the debris. Next, use an air filter cleaner and soak the filter with the solution. And then, rinse your air filter with water. Continue to wash your filter until the water runs clear.
On the other hand, you should replace the air filter if you find it broken.
04. Fuel Pump Gets Defective
Engine bogs when given throttle! If you experience this issue, you can suspect the fuel pump. A fuel pump is an indispensable component of the fuel system that pumps oil to the engine. If the oil pump gets defective, your engine will not receive sufficient power. And guess what, your car won’t take throttle due to lack of oil. There are also other symptoms of a bad fuel pump, including:
- Loss of power or unresponsive acceleration
You must replace the fuel pump right off the bat if you notice any of the signs we mentioned above. Otherwise, it may bring severe damage to your car engine.
05. Dirty Fuel Filter
A clogged oil filter is what causes an engine to bog down when accelerating. It is because the fuel system fails to get sufficient oil it requires to operate the engine optimally. Consequently, the lack of oil in the fuel system will lead to rough idling.
Now, you may ask- how can I understand if the oil filter gets dirty? Well, metallic noises, low oil pressure, poor engine performance, and engine overheating are some symptoms of a bad fuel filter.
Replacing a fuel filter is the only solution to this issue. Just go underneath your car, place a pan right under the drain plug, and unplug the drain plug. Then, pull out the fuel filter and replace it with a new one.
06. Fuel Pressure Issue
You already know your engine will stall or bog on acceleration because of a lack of lubrication. There is a lot to blame when it comes to faulty fuel pressure. A dirty fuel filter, defective fuel pump, and gummed-up air filter are some culprits we already discussed above that cause fuel pressure issues. Sometimes a fuel gauge that gets defective is the caveat behind this issue. If the fuel gauge is at fault, it will show the wrong reading.
A fuel pressure test is the only solution you can perform to determine whether it’s a problem with fuel pressure or not. The correct Chevy 350 TBI fuel pressure is between 9 to 13 PSI.
If you don’t get the reading, you should inspect the fuel filter, fuel pump, and other potential things that cause low fuel pressure. Don’t forget to check the fuel gauge itself. Replace the gauge if needed.
Lastly, don’t hesitate to bring your Chevy to a mechanic if you fail to solve this problem by yourself.
07. Defective Temp Sensor
A faulty coolant temperature sensor can cause the engine to stall on acceleration. Modern cars like Chevy 350 TBI rely on a number of sensors to determine the engine temperature. If the temp sensor is at fault, the computer thinks the temperature is around -30 degrees. That’s why it increases the fuel making the mixture too rich.
Changing a coolant temperature sensor is not rocket science. Just follow the below step-by-step
guide to replace the temp sensor.
- Ensure the engine and coolant system get completely cooled. Then, disconnect the battery to ensure safety.
- Pull out the plastic engine cover and locate the temp sensor. You can find it near the thermostat housing. It would be best to check the manual diagram to locate the sensor.
- Once you find the temp sensor, we recommend you drain it partially. Then, pull out the electric connector from the sensor and remove the temp sensor.
- Unscrew the coolant sensor from the coolant passage by using a wrench.
- Finally, insert the new sensor and put everything back into its place.
08. A Bad Regulator
A fuel pressure regulator regulates the fuel pressure of your car. It ensures the fuel pressure doesn’t go higher than the recommended level. When the oil pressure goes high, the regulator stops the fuel flow and returns the excess oil to your fuel tank. You will experience the following issues if the regulator goes bad:
- Poor acceleration
- Engine misfires
- Black smoke coming out of the exhaust system
- Excessive fuel pump noise
There is no option except to change the regulator when it goes bad. We recommend you watch this tutorial to learn every procedure to replace the fuel pressure regulator. Alternatively, you can hire a car mechanic to do this task for you.
09. Defective Ignition System
A faulty ignition system can also cause your car engine to bog. Your engine will not get the power it needs for proper operation. if the spark plugs, rotors, or other wiring have problems. As a result, your engine will bog or hesitate on acceleration.
Start with inspecting the base timing of your chevy. Then, detach the EST bypass connector. The connector will have a brown wire with a black line and connector. Once you pull the connector, inspect the timing. We recommend you get a 0 base timing. However, it is allowable to add a bit more timing as per your requirements. Finally, put the EST connector back into its place.
What does 350 TBI mean?
The 35o indicates engine cc. On the other hand, TBI stands for Throttle Body Injected.
How much fuel pressure does a 350 TBI need?
A 350 TBI needs only 15 PSI of fuel pressure to run.
Can you put a carburetor on a TBI engine?
Yes, you can put a carburetor on a TBI engine.
Why does my car bog down at full throttle?
Your car will bog down at full throttle if the air filter or spark arrestor gets clogged up that won’t let your engine breathe.
Can spark plugs cause bogging?
Yes, a spark plug can cause bogging if it gets clogged or loosened. If the plug gets blocked, you engine can’t ignite all the fuel.
Chevy 350 TBI stumbles on acceleration because of leaky vacuum lines, worn-out plugs, and others that we mentioned above. What you need to do to solve this problem is to follow all the troubleshooting steps we described. If you fail to fix the bogging issue after trying out those steps, we bet there your car goes through a serious problem. In this regard, you should bring your car to a certified mechanic.