after start up the black smoke goes away
2007-09-06 02:48:40 · 5 answers · asked by ford f 1 in Cars & Transportation ➔ Car Makes ➔ Chevrolet
check your EGR valve.
2007-09-07 19:00:01 · answer #1 · answered by Anonymous · 0⤊ 0⤋
You are experiencing excess fuel being burned on start up and most likely you are also experiencing a long crank before start up as well as poor fuel economy. This is most likely a case of the CPI system leaking inside the intake and upper plenum. When you first start the motor there will be pools of gas inside the intake from where the CPI has leaked it and that gets gulped and burned by the motor which pukes it out the exhaust. The hard start is because the motor is choking and the fuel pump is trying to catch up with pressure to make up for the loss. The economy issue is the same as the motor is recieving unmetered gas which the PCM attempts to correct for. The PCM will normally set a code or two if this gets bad. Check the fuel pressure with a guage while it is running and then turned off. It should not leak pressure away very fast and actually should hold around 50 psi.
2007-09-06 14:12:11 · answer #2 · answered by Deano 7 · 0⤊ 1⤋
The black smoke means it is running rich. Running rich on cold start is normal because the oxygen sensors do not start working until it reaches operating tempature. In most cases you should not see black smoke, but if your vehicle has high mileage, this could be caused by leaky fuel injectors.
It is not oil in the cylinders at all. Oil burning is a bluish/whitish smoke.
2007-09-06 10:27:02 · answer #3 · answered by Anonymous · 1⤊ 0⤋
Black smoke - running rich
Bluish smoke - burning oil
You could also be getting some blow by from worn piston rings.
2007-09-06 10:32:44 · answer #4 · answered by twinturbo1994 4 · 0⤊ 1⤋
OR WORN PISTON RINGS?
2007-09-06 10:00:47 · answer #5 · answered by Anonymous · 0⤊ 2⤋