Fuel economy poor - 2001 S40, 250 per tank

BomTillington · Post by **BomTillington** » 12 May 2013, 16:33

Hey everyone thus fuel economy is killing me. I have already done the headgasket other gaskets and a cat and o2 sensors I also did the full pcv system I do plugs and oil religously have a new air filter but have a k an n filter fan decide whether to put it on its a 2001 s 40 and I only get 250 miles to the tank I was curious if the aftermarket cat is choking out the exhaust its a turbo please help

BomTillington · Post by **BomTillington** » 12 May 2013, 19:34

Can someone please help

Post by **matthew1** » 12 May 2013, 20:36

No codes, Check Engine light? When did the poor fuel economy start?

BomTillington · Post by **BomTillington** » 12 May 2013, 22:50

I have intermittent o2 sensor codes but I replaced them with Volvo sensors so that what I don't understand and its been going on for a long time I think it was about time that I did the catalytic converter it seems as though the cat is choking it out also I seem to have a coolant leak but I can not seem to find where its coming from but it's getting on the exhaust and you can smell on start up and the mixture is super rich cause my exhaust pipe is full of soot and I haven't burned a drop of oil

Post by **matthew1** » 12 May 2013, 23:42

"The easiest test for converter plugging is done with a vacuum gauge. Connect the gauge to a source of intake vacuum on the intake manifold, carburetor or throttle body. Note the reading at idle, then raise and hold engine speed at 2,500. The needle will drop when you first open the throttle, but should then rise and stabilize. If the vacuum reading starts to drop, pressure may be backing up in the exhaust system." - http://autos.yahoo.com/maintain/repairq ... 083_0.html

Additionally, if the vac gauge needle gradually drops as the engine is running or as rpms increase, it's a clog. Clogged exhausts are usually the cat.

BomTillington · Post by **BomTillington** » 12 May 2013, 23:47

I'll give that a try I don't think it's clogged I just thing its smaller that the or and I believe it's restricting my exhaust cause I feel a performance decrease mpg decrease and the o2 code

BomTillington · Post by **BomTillington** » 12 May 2013, 23:53

do you happen to know the normal idiling vaccum reading with an oe cat and at rpm so I have something to compare it to?

Post by **matthew1** » 13 May 2013, 00:07

I don't, sorry.

BomTillington · Post by **BomTillington** » 13 May 2013, 18:06

Mine come on at about 230 and takes the same amount to fill it up