Thursday, September 22, 2011

How do you check to see if the EGR valve is working?.?

I have a 93 Grand prix and my mpg has gone from about 22 mpg to around 15~16 ish the car isn't as quick as it once was their is no soot or anything at the exhaust tips. The O2 sensor is a year old and has about 12,000 miles on it the air filter is okay the fuel filter is okay I checked the spark plug gap and its fine. My car has the 3.1L MPFI engine it has the digital EGR valve with the three solenoids how do I test the solenoids to see if they are working and should I change the PCV valve as well?. the grommet is new but the valve is the original. I run 87 oct in the car the engine does not have anything wrong with it mechanically and the fuel injectors are working as they should the engine doesn't stumble or miss.How do you check to see if the EGR valve is working?.?
that is a linear egr valve. if it malfunctions it will throw a code for egr flow. but there is no way to check it without a 5 gas analyzer and a scanner that will command it to turn on and off. it sounds like the lower intake manifold is leaking that is what happens to almost every 3.1 put out by general motors. 15 years experience as a diagnostic tech. used to work at the chevy dealer as the lead tech.

the vacuum being fine and throttle body being ok still does not rule out an intake gasket leak. the lower intake on those leak oil and coolant into the combustion chamber and externally in small amounts. but another common problem is the ignition module which is under the coil packs. it could be getting hot and cutting out due to a short. you need to check the spark and if it is weak once warm then change the ignition module and coil packs. Another common problem is the fuel pump. how new is the fuel filter and what is your fuel pressure. it needs to be within spec. if it is even 2 lbs low it will cause drive ability problems.
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