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Disable EGR valve

I have a '95 SW2 twin cam (is this redundant?) and it is showing symptoms of the sticking EGR valve problem for the second time in a year. The first time, I cleaned out the EGR as well as I could manage. This time around I am wondering if I could simply disable the EGR function by replacing the gasket with a piece of gasket material with no holes in it, so the EGR is simply blocked.

For the record, this is the electrical EGR valve. I think Saturn changed from vacuum to electric for this valve sometime around the '95 model year.

What impact will this have on performance? Mileage? Safety? My understanding of the EGR is that it simply lets the engine run a bit cooler under certain conditions, to reduce NOx emissions. Honestly, I don't drive the car under those conditions (high speed) very often, but I don't want my car to stall out on me any more either.

Reply to
Detector195
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The Check Engine light will be on due to no EGR flow being detected (depending on the specific engine, it detects this either by looking for the increase in MAP when the valve opens, or the mixture change from the O2 sensor).

The EGR doesn't make the engine itself run cooler, it dilutes the air-fuel mixture with inert exhaust gas during part-throttle operation. This reduces the peak combustion temperature, which in turn reduces NOx formation.

As well, the engine may be hitting the knock sensor more often, since EGR operation tends to inhibit spark knock, and the spark advance is set assuming there will be EGR flow.

That, and the fact that what you propose would violate federal and most state laws in the US.. ;-)

Reply to
Robert Hancock

Just an update -- I confirmed code 32, which is the generic EGR failure code. Being familiar with the routine, I pulled the EGR, which is quite accessible, and indeed it sticks open if I push it open. Following the routine, I got it freed up and cleaned out as well as I could with carb cleaner. This time I got a better look inside with a flashlight, and saw actual chunks of carbon. The entire inside of the air system of this car is coated with this stuff. I am leaning towards not disturbing any of this, since it seems happy where it is.

Reply to
Detector195

Hi, I have had similar issues with my '91 s10 blazer. Go to a chevy dealer (a saturn dealer might have it as well)and pick yourself up a can of GM top engine cleaner. Follow the directions on the can your problem should go away. And it will clean all that carbon out. My '91 s10 it has a throtle body so it was easy enough just to pour the stuff in there. my '93 s10 blazer and '02 saturn sl1 have multi port so I poured it through the power brake booster hose. They do not tell you this step in the directions but after you let it sit for 15 minutes then pour the rest in while it is running take it on the hi-way and run at 70-75 mph. You will see all the carbon come out of the tail pipe in the form of nasty and I mean nasty smoke. Do not worry it will go away after your run on the hi-way.

Paul

Reply to
Paul Dougherty

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