Engine Performance problem
1993 Saturn SL1 4 cyl Front Wheel Drive Manual
I have a misfire or hesitation at small throttle openings, the problem goes away if I disconnect the vacuum line to the EGR valve. I have replaced the valve, the solenoid and substituted the PCM all to no effect. There are no codes. I can read the output from the PCM but I do not know the exact conditions under which the valve is supposed to open. If the valve is opened manually the engine stalls. The valve I have and a replacement valve (from Saturn) are both negative back pressure valves, that is, vacuum on the pintle opens the internal valve preventing the solenoid vacuum from opening the valve. But the pintle is exposed to exhaust gas so I am wondering if the valve should be a positive back pressure valve. The valve part # is 21008566 and it is marked with the GM number 21000122 which is identical to the part number of the valve fitted to the car.
have the same problem?
Tuesday, March 10th, 2009 AT 4:52 PM