1998 Chevrolet Malibu hard start and burning rich

LWADE214

MEMBER
1998 CHEVROLET MALIBU
2.4L
4 CYL
FWD
AUTOMATIC
140,000 MILES

Replaced catalytic converter that was completely torn up inside. Replaced fuel filter, cleaned throttle body, cleaned MAF and MAP sensors checked spark plugs for build up as well as reset gaps. Tested oxygen sensor and it seems to be reading fine. Hard start 95% of the time now and especially worse when the temperature outside is hotter. Burning rich and strong smell of gasoline every start. Not sure what to try next, maybe replace oxygen sensor as another cheaper option?

3 Replies

JDL

MECHANIC
16,098 POSTS

Can you check fuel pressure? Does the pressure drop like a rock when you turn off the key? If so, you could have a fuel leak, fuel injector or pressure regulator leaking. The coolant temp sensor could also cause the engine to run rich.

Can you check for applicable trouble codes? To check codes yourself, at the least you need an obd2 code reader. Some of the national brand auto stores will check codes for free.

Smell of the oil on your crankcase dipstick, does it smell like gas?

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Sunday, June 8th, 2014 AT 1:09 PM

LWADE214

MEMBER
3 POSTS

No way of checking the fuel pressure myself. Any idea of where the coolant temp sensor is? Also there is no check engine light, so the computer is not throwing any applicable codes to check. Crankcase oil does not smell exactly normal, what could this suggest?

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Sunday, June 8th, 2014 AT 7:23 PM

JDL

MECHANIC
16,098 POSTS

Throwing parts at it isn't the way to go. In the past, I've had inactive codes point me in the right direction, no lite.

Evidently, you have no Schrader valve on this vehicle. There is a kit you can use to tee into supply line, has the proper connectors. If your going to work on your own vehicle, you certainly need to be able to check your fuel pressure.

Also, check the vacuum line at the pressure regulator. The pressure regulator is on the end of fuel rail. Take the line loose, if gas in the line, fuel regulator is faulty.

As far as the coolant temp sensor, no way from here can I be sure it is faulty? Should be located on the end of engine, the end is opposite from the drive belt end. The drive belt end is the front.

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