Skip the auto shop - Our mechanics make house calls

Q: Car only starts when I pump the gas pedal.

asked by on

I replaced the throttle body and now the car will only start when I pump the gas pedal. What do I need to have fixed?

A: From this description it seems that there c...

From this description it seems that there could be separate issues happening to your Mitsubishi Eclipse. The three most common reasons I see for a car unable to start without pushing the gas pedal include; the throttle body gasket may have been installed incorrectly, the idle speed control screw needs to be adjusted and finally the throttle position sensor may need to be adjusted.

Every car may be made up of the same parts but they all install and work slightly differently. Sometimes parts aren’t ready to install right out of the box so it is necessary to make certain vital adjustments to the part, in order to have the throttle body do its job properly. If this is the case, a trained professional can easily diagnose this concern on your car and determine if this is indeed the problem and will be able to make the adjustments necessary. While they are doing this, they can also inspect the idle speed control screw. The engine will need to be running, allowing the screw to be adjusted to run at the specified RPMs for that vehicle. Finally, with the throttle position sensor, a certified mechanic can adjust it by using the manufacture specs, it needs to be installed and clocked (turned a specific way) then a voltage meter is used to check the signal voltage (signal voltage is 5v and as you step on the gas pedal the voltage will vary from 1.5 up to 4.5 volts to tell the computer where the position of the throttle is and use his information along with other sensors to determine how much air and fuel are put in the engine) to ensure that the voltage specs are in the proper range.

As you can see, it is important to have a certified mechanic to look over this problem so they can diagnose which part may be failing and get you back on the road safely.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Why would I lose my brakes and power steering after changing my ball joint?

This should not have any effect on your power steering or power brakes as these are separately controlled systems and may be a part of a larger problem. I would suggest having a professional mechanic, such as one from YourMechanic,...

Q: Coolant leaking from exhaust manifold area (behind the engine)

Hi there. Before we condemn the head gasket or cylinder block, we need to consider that the coolant may be coming from another location. This could be a hose, throttle body, thermostat, water pump, heater hoses, or freeze plugs. A...

Q: Car tries to turn over, but doesn't start

It sounds like you may have had your fuel pump go bad. The sputtering could have been due to low fuel pressure. As the pump worsened, the symptoms worsened until it got so bad that your car would not start....

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...