I have a 2001 S40 1.9T. We took it out last night, drove about 35 miles and shut it off for an hour. When we went to start it, it wouldn't stay running. Without giving it gas the RPMs would drop drastically then it would stall. We were able to make it home, it just stalled as soon as you let off the gas. My initial thought was bad gas and maybe there was water in it so we put dry gas in, but it didn't work. The check engine light has been on for about two weeks now but have not retrieved the codes yet. From reading other forums, it sounds like it could be a vacuum leak, o2 sensor, etc., is there an easy way to see if I have a leak prior to bringing it to my dealer? Any other ideas what may be causing it?

 

Look on the front of the engine there is a hose that goes from the engine to the intercooler. It is part of the idle circuit. That hose is known to break. Also have someone start it and keep it running and look for a vaccum leak.

 

I had intention of trading in my S40 for an S60 tonight...As stated earlier, I have the wonderful stalling problem going on. I was upfront with the dealer and told them what was going on prior to going to the dealership. When I arrived they pulled the fault codes (which I didn't write actual codes down) but they consisted of 02 sensor, MAP sensor, MAF sensor and cam shaft sensor. All intermittant codes. Is it possible that all these codes are related to the stalling problem? I have had the cam shaft code come on in the past and with computer download and reset it never came back on til this stall problem started. Dealer came back with estimate of 1500-3000 of repairs so we had to nullify the deal. If I knew that fixing the obvious problem (02 sensor) would clear the other codes I would feel much better but just can't imagine having to fix all items.

 

If it stalls and doesn't start right up unplug the Mass flow and see if it starts if it does then the MassFlow is bad.

Could be the Cam sensor.

Could also be the Map.

I would look at the O2 sensor last. (usually won't make it stall)

 

Tech,

Thanks for the quick responses, do you have a diagram of the 2001 s40 engine or can you tell us exactly where the mass flow is and what we are looking for to try this out?

Thanks!

 

The Mass flow sensor is in the Air filter Box. Where the Hose attaches to it.

 

Here's the scoop, I have to give it gas to keep it running once it starts or else it will stall. We unplugged the mass flow sensor and started it and it did start however i still had to give it gas to keep it running. We have checked hoses and cannot find any apprarent leaks...Dealer offered to settle for $750 to fix...do you think it would be worth eating the $750 in case it does end up being a cam shaft sensor (I assume that would be the most expensive problem)? Also what is the difference between the mass flow and the map sensors?

 

One more thing I just remembered Check all the fuses in the Fuse box under the Hood.
See if any are Blown.

There is a Valve in the induction Hose that goes bad soemtimes and causes the same problem.

 

Just to be an ***, What is "dry gas" I dont know of this.

 

Dry gas is a term used for a fuel supplement (Example would be HEET) that you add to your gas tank to remove water from the gas. It is alcohol based.

 

So the term gas is used incorrectly, it is actually alchol?

so water mix with alchol so it can burn off in combutstion.

I guess the term dry is used incorrectly as well then as alchol is actually a liquid.

I guess if it were me I would have called with wet alchol.