hey guys just wondering the y pipe gaskets went bad on my 90 gmc jimmy 4.3 it gets loud and lights up check engine light indicating a lean condition im having these done wed im just curious do u lose power when these go bad because this truck has lost some power even after complete tuneup and new filters im just hoping this may be the reason
y pipe gaskets
- Thread starter jc1990
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I had them go in our 1993 Chevy 1/2ton at work with the 305. It lost a lot of power, because there is no backpressure. Didn't have a Check Engine Light, but I could see it happening, because all the exhaust is leaking out before the O2 sensors, therefore, it thinks it is running lean. If the O2's read lean the computer might also richen the mixture to compensate, so you probably lost some gas mileage too.
Are they gaskets or donuts? If they are donuts they need to have a metal sleeve inside of them. W/o the metal sleeve they will burn out.
You could have a clogged catalytic converter. I've had donut gaskets leak due to high backpressure with a clogged converter. The symptoms went something like this:
At idle, the engine ran normally.
At part throttle, the engine had very little power, still ran quiet.
At full throttle, the engine had ok power... and I could hear the donut gaskets leaking at full throttle- due to high backpressure.
At idle, the engine ran normally.
At part throttle, the engine had very little power, still ran quiet.
At full throttle, the engine had ok power... and I could hear the donut gaskets leaking at full throttle- due to high backpressure.
im hoping the cat converter is not bad ive got so much into this truck i know 1 thing though i went thru 18 gallons of gas in 200 miles 70 highway 30 city after a full tuneup so im hoping it solves that prob.
i would say with that horrible of fuel mileage that your cats are plugged
Originally Posted By: mechjames
I had them go in our 1993 Chevy 1/2ton at work with the 305. It lost a lot of power, because there is no backpressure. Didn't have a Check Engine Light, but I could see it happening, because all the exhaust is leaking out before the O2 sensors, therefore, it thinks it is running lean. If the O2's read lean the computer might also richen the mixture to compensate, so you probably lost some gas mileage too.
Except there's only one O2 sensor and it's before the y-pipe gaskets.
I had them go in our 1993 Chevy 1/2ton at work with the 305. It lost a lot of power, because there is no backpressure. Didn't have a Check Engine Light, but I could see it happening, because all the exhaust is leaking out before the O2 sensors, therefore, it thinks it is running lean. If the O2's read lean the computer might also richen the mixture to compensate, so you probably lost some gas mileage too.
Except there's only one O2 sensor and it's before the y-pipe gaskets.
I've replaced these "Y pipe gaskets" on all of my cars, they all leaks after a while, but not enough to cause a CEL or fail emissions. Are you sure it is not from somewhere else like a crack? Have you tried spraying soap water (diluted dish soap works great) to see if it is really a leak?
the place i took it to told me this they replaced them said check engine light went off so ill see when i get back tommowrow i know it was pretty loud though
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