Engine Mechanical problem
1990 Chevy Lumina 6 cyl Front Wheel Drive Automatic 220000 miles
I submitted a question several days ago. 1990 lumina hard to start cold or hot. Your response was to test the fuel pressure first, if that checks out, then change the ECT sensor, TPS, and the ingnition switch.
I tested the fuel pressure and not sure what to make of it. First I tested the fuel pump by applying 12 volts to the test terminal. All is well, I hear the whinning sound. Now connecting the gauge to the schrader valve, key in the on position, the pressure is low, 10 psi. I started the car, pressure jumped to specs, 32 psi. From there all checks out OK. I tapped the throttle, pressure jumps about 5psi. Removed the pressure regulator vacuum, pressure jumps about 10 psi. I did change the ECT, no effect on starting, however I believe the idle is improved and the exhaust smells better. I believe it was a little rich before.
I did notice when tapping the throttle, there is a very slight hesitation. Very slight! What should I do at this point? Why is the fuel pressure low when the key is in the ON position?
have the same problem?
Thursday, July 29th, 2010 AT 5:32 PM