Hey all....

Need a hand with something... I have an 05 S60 T5 that is having some trouble with cold starts. Cold is a loose term seeing as it's flippin hot in Phoenix, but more often than not when I start the car after it sits overnight or after sitting at my office all day, the motor sputters like crazy and shakes like it is misfiring on most cylinders. It will continue to idle like this for a while, so what I tend to do is turn off the ignition, and start it again. The second time around it fires right up like there is nothing wrong. I notice a raw fuel smell after it does this, but I think it's just because the motor is not firing correctly at first. I have had the car about 6 months or so, and have been having this issue for the last 2. The mileage is roughly 59k at this point. Anybody have any ideas? I'm thinking about swapping out the plugs, but I would be surprised if it was that easy.

Thank you in advance!

 

Howdy, I have this same problem. Sometimes is worse than others, but like you say it's only when the motor is cold; never after warmed up. It will sputter and shake and finally smooth out like nothing happened. I don't notice a fuel smell or anything.

 

Well, glad to see that it's not just me. I have read posts by others who are having similar issues, but none of them sound quite like what we are seeing. I really do hope that it's something pretty easy to fix, I really don't want to have to start throwing a bunch of money at this if it's something easy to handle.

 

Someone mentioned to me that it may be either that the fuel rail is not holding enough fuel pressure on cold starts to keep the motor idling correctly, or that maybe there is a cold start valve that I need to replace. Does any of this sounds like it may be a possibility? I got some fuel injector cleaner (gas additive) that I may try to see if the injectors are gunked up, but that's kind of a shot in the dark.

 

This isn't necessarily a diagnostic on your problem, but it could help. When cold (i.e. not at or near operating temp) fuel injection through the computer, acts like a carb's choke. It sprays additional fuel into the cylinder to enrichen it. The cold stumble sounds like an overly-lean cold mixture. The clue is that the problem disappears when the engine is warmed up. That's when the cold start enrichening shuts off. I do not know, however, why you smell raw fuel unless its via the exhausting of unburned fuel. An underhood leak is also possible, and that's likely to lead to a very hot running, albeit for only a short time, car.

Get it diagnosed and fixed as your catalytic converter isn't long for this world if raw, unburned fuel is entering it. A fuel leak can, and likely will, lead to an underhood fire which will cause no end of trouble.

 

So... my fierce stumbling issue has changed a little bit....

I swapped out my plugs, and just because I wanted to, I swapped in a K&N filter. I assume the filter would have nothing to do with it, but I wanted to make sure it was mentioned.

The really bad stumble pretty much went away after the plug swap, but it's doing something else now...

When I start the car when the motor is cold, it will pop and spit, and idle slightly rough until it warms up. Once the motor is warm, its all good.

Thoughts?

Thank you so much!

 

You're treating symptoms, I think. Fresh plugs probably gave improved spark with better chance of lighting off the too lean cold mixture. I still think you'd better get the engine scoped from a cold start so it just isn't stored codes being read, but an actual mechanic
seeing and hearing the problem.

 

You are probably right, but I am trying to exhaust all my options before dropping it off at the dealer or hunting down a mechanic. Trying to pinch a few pennies if I can.