The truck has just short of 200,000 miles. It's making black smoke when I accelerate. The Air filter is clean.
2007-01-24 20:09:40 · 5 answers · asked by djm749 6 in Cars & Transportation ➔ Maintenance & Repairs
The EGR valve allows exhaust gases to circulate through a passage in the intake manifold to heat up the intake air to allow for better cold start combustion. If it is bad it can either stay open or stay closed if it stays closed then it would result in poor cold operation and black smoke during the first few minutes of operation in cold weather. if it stays open then it would result in slightly worse fuel economy. IT SHOULD BE REPLACED when you replace your spark plugs or during a tune up every 50,000 miles or whenever your owner's manual says a tune up is due
Take your truck to an Auto Zone or another car parts store and get it's trouble codes scanned. Sounds to me like you truck is running rich like the other guys have said. this means your engine is getting too much fuel and carbon(black smoke) results. this is a problem with your fuel system thinking it needs more fuel than it actually needs. This is usually the default setting for engines when there is a problem, since putting too little fuel makes the engine run hot and can ruin it where as running the engine rich just leads to carbon build up which can be reversed when the engine is running correctly. The O2 sensor is probably bad, and maybe there is a vacuum leak around the throttle body or the manifold. To easily check this spray WD-40 around the base of the Throttle body and where the manifold meets the heads if the engine suddenly surges or increases in idle then there is a gasket leak. Also check any vacuum lines for deterioration, which would allow extra air to enter into the combustion process which the O2 sensor picks up and increases the amount of fuel as a result.... so either the O2 sensor is bad or there is an vacuum leak.
2007-01-24 21:34:09 · answer #1 · answered by mister_e79 3 · 0⤊ 0⤋
I had a 91 Suburban with 350 and had many emission issues with it. First you need to do a compression test on your engine, black smoke ad 200,000 miles would lead me to believe the rings are shot and you are burning oil. if your compression test shows your cylinders around 170 to 210psi and are within 10 to 15% of each other than I would get the trucks ECM scanned, if there are no codes chances are your computer is bad, this was an issue with 91 trucks, the computer are know to fail. if there are codes then replace the equipment associated with the codes.
2007-01-24 20:40:08 · answer #2 · answered by furyguy 2 · 0⤊ 1⤋
The black smoke means it is running rich on fuel. Also check the wires and plugs. It might help to replace the o2 sensor as well
2007-01-24 20:20:22 · answer #3 · answered by tripled2099 2 · 1⤊ 0⤋
As long as you can suck on the end that faces toward the intake and you feel a vibrating partial vacuum resistance the valve will work fine.
2016-03-29 01:37:18 · answer #4 · answered by Anonymous · 0⤊ 0⤋
you should consider replacing it along with your ecm
2007-01-24 20:15:00 · answer #5 · answered by mercury_marsh 2 · 0⤊ 0⤋