I have a 2000 Chevy Prism (same as the Corolla) which has had the check engine light come on occasionally for over a year now. It started turning on more then normal about 2 months ago so we brought it to the dealer. They told us the car needed a new catalytic converter and O2 sensor. But because…

First, find what the error code(s) is(are). That will tell you what part of the system is having a problem, but not specifically what to replace/repair. Post the code back here for help. It will have an ID# like P0123. If it is an O2 sensor code a good mechanic will look at the signal coming out of …

You did not state how many miles are on the car but I don’t think the O2 sensor(s) have anything at all to do with the hard starting problem. By hard starting, do you mean it cranks over for a bit before finally starting? If so, this could be a loss of fuel pressure issue (leaking fuel pump, fuel p…

The Prism has 120K on it. And yes, instead of starting right up it cranks over for5-10 seconds before it starts up. Interestingly we have found that if we let it turn over for a few seconds and it won’t start, then we stop turning the key, then it will start up right away… most of the time. I sup…

Try this: Turn the key to "ON, wait 5 seconds, then turn the key to “START.” If the engine starts normally the problem is loss of pressure in the fuel line overnight or when the car sits for a time. There is a check valve in the fuel system to maintain fuel pressure at the injectors. If the valv…

Turning the ignition on for five seconds does nothing to reprime a leaked down fuel system. That’s because the fuel pump only runs once for 1-2 seconds each time the ignition is turned to the run position. To reprime a fuel system that has leaked down requires turning the ignition to the run positio…

I agree with mcparadise’s suggestion about how to test for loss of fuel pressure and about the fuel pump check valve. Loss of fuel pressure means air in the lines and it takes a bit to purge itself. (Think of a garden hose lying outside, turn the water on, open the nozzle, and water will sputter and…

It’s doubtful that the oxygen sensor is contributing to your hard starting problem. The O2 sensor doesn’t come into play until well after the engine is started. When you start your car, the computer is excluding some of the sensors from the mix, including the O2 sensor. After the engine has been …

I had issues with my Pontiac not wanting to start sometimes not at all but sometimes if I could get it revved up and hit the gas quick enough it would stay on but I have replaced a bad O2 sensor now and now it is cranking fine

Other than fouling the plugs I can’t imagine any reason that a bad O2 sensor could cause extended cranking to start. That diagnosis seems a real stretch.

Hard start due to bad O2 sensor?

Maintenance/Repairs

pleasedodgevan August 23, 2008, 4:49am 9

If you can fix the problem first, you can change the O2 sensor later. You may have to try changing the ignition switch first, seeing as no mechanic can do better at finding the problem. Somebody should read the codes.

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Hard start due to bad O2 sensor?

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