Well the XF almost left me stranded tonight. It tried to stall in the middle of the road when I was giving it some throttle turning at a green light. It missed really hard and almost died... but ran good enough to pull over/coast into a gas station and park. The car started bucking and going crazy and the CEL and Battery Light came on.

Oddly enough, the car cranks up just fine and all the lights work, a/c, radio etc, but when you try and rev up the car just a little in either neutral or park, it hesitates really bad and wants to stall. None of the lights dim when this happens though. If you try and drive it and take off too fast it will stall and the battery light will come on. It wouldn't crank for about 10 seconds, no clicking or anything, then it would slowly turn over things will go dim and then turn on. My battery is cracked on the top and corrodes pretty bad. Luckily I was able to slowly drive home. When your light on the throttle and go at a steady speed it's just fine.

I'm not thinking this is related to any of the no start issues (crank position sensor, fuel pump relay, modules etc) since it cranks just fine. I just wanted to make sure I'm not overlooking something, since my girlfriends mom has an SLK320 and has tons of the same problems. She said she thinks it sounds more like when her module went bad and it's not the battery.

Sadly I just payed almost $100 having the car looked at and they said it's just fine, it's been throwing no codes until tonight. The car has been having hesitation after it heats up and power surging when going with traffic (another post I made). The mechanic said I was getting unmetered air at the MAF and I just needed to tightened my intake. I'm thinking this is the problem I've been dealing with all along.

I'm getting a ride to work tomorrow then I'll be able to look more into things, any help at all would be much appreciated.

 

Did anyone bother to check fuel pressure...??? no codes will show up on a faulty pump..when the car is about to stall a battery light is normal ...as for a cracked battery..that can't be good if battery voltage is down your going to have all sorts or driveabilty problems, also under the battery tray is a major wire harness.. if you remove the battery your going see some corrosion on the wiring

 

Well, I know the battery will need replacement at some point because it's cracked, but if it's not causing the problem at the moment, I can't afford to replace it. I was going to pull it out tomorrow and have it checked at the auto part store. I'd think if it was a bad battery it wouldn't want to crank, but maybe it's just bad enough to where it can't handle any load from the motor? That sounds silly to me.

I had thought the car had a bad o2 sensor or cat from the symptoms it's been having, since I already replaced the MAF, but they said everything was fine. I don't know if they checked any of the fuel related stuff. Tonight just totally caught me off guard, it was running perfectly fine all day. I need to know how to check if that module is bad in the box beside the battery where the ECU is. I heard you have to open it up and look carefully at a certain part of it. Sounds very delicate and touchy to mess with. Perhaps it could be something with the fuel pump as well, just too many possibilities.

 

Search the forum for ...crossfire documentation collection...member mmz_timelord has several service manuals and other good stuff for download, most of the service manuals are pretty genric when it comes to basic even if they don't match your year..

 

I would start with the most obvious - replace the battery. A battery that is cracked and corroding can cause havic on electronic components causing them to do unexplainable things. I know this is a MB, but a few days before the battery in my Durango took a dive, I was getting all kind of weird things going on - stalling, hesitating, certain idiot lights coming on for no reason, trans not shifting properly. A new battery put everything back to normal.

James

 

Well I took it to the stealership and they said it's the MAF again, and my intake is the problem. The last shop I took it to said I had a vaccum leak and my intake was also the problem. Unfortunately, I don't have the stock airbox anymore, so I guess I'll have to replace the MAF again and go back to the stock setup. I'm pretty dissapointed considering I never hear people with the TVT or Needswings intake having problems, but the one I made is.

 

Sorry for the double post, but just to confirm... I held onto the original MAF, so when I got home I installed it, and they was right, it drives fine again (of course this ones bad too, but not nearly as much). The new MAF is completly dead, its no different then having the sensor unplugged. Maybe the NeedsWings intake will fix the problem with yet another new MAF / That's a good $700 down the drain.