ok on the battery , max charge voltage should be 14.2 volts , no more , the EGR valve is bolted to the carb adaptor plate , a steel tube about 5/8 inch goes into it , the other end goes to an elbow on the exhaust manifold , to bypass the valve you can unscrew the two bolts on each side of the EGR valve just enough so it can move , make a shim out of a beer can to slide behind the valve and cover up the hole there , tighten the bolts back up , the EGR should be blanked off by doing that so you can test , or leave it that way if it runs well or better ,, and on the smell again you have a wagon , the tail pipe does not go straight out the back of the car , it suppose to make a 90 degree turn to the side of the car , if you have bad seals in the back of the lift gate you will get a draft of exhaust gas that will be pulled in from that area , like I said you have a leak from the exhaust or a place the fumes will get in , if it is very bad you just might fall asleep driving down the road ,