Is dry gas fixing my car's starting problem?

Dear Car Talk

Dear Car Talk | Jun 01, 2001

Dear Tom and Ray:

I have had some problems starting my '95 BMW 325i on cold, damp winter days. Both times, the problem disappeared IMMEDIATELY after adding a container of "dry gas." When I discussed this with my dealer service representative and asked if I should add dry gas prophylactically (no, this is not a dirty word), he said it wouldn't hurt, but it's not necessary. He said there's already a desiccator that dries the air before it enters the tank. Is this true? -- Steve

RAY: No, it's not true, Steve. Our representative at BMW says that none of the BMWs have dessicators. Although when we suggested that he introduce an optional, gold-plated aluminum-alloy dessicator with a BMW emblem on it for $379.95, he sounded interested.

TOM: I doubt the dry gas had anything to do with solving your problem, Steve. I think that was just coincidence. It could have been the TIME you spent adding the dry gas ... or just dumb luck.

RAY: It could be any number of things. But since it happened twice in damp weather, I'd probably suspect an electrical component first. It could be something as simple as a weak battery that just didn't crank fast enough the first time you tried to start the car.

TOM: It could also be a bad crank-angle sensor, a bad coolant-temperature sensor, or some other ignition or fuel-injector component.

RAY: So if this starts to happen regularly and you want to take care of it, you'll need to go in for a "complete workup." Ask them to start by "scanning" the vehicle for stored codes.

TOM: The computer keeps track of any faulty signals it receives from individual components. And when your mechanic hooks your car up to his scanner, he can read the codes and get some very good hints as to what might be wrong.

RAY: For instance, if he sees a "code 1223" he knows the coolant-temperature sensor is out of specification.

TOM: Or, if he sees a "code 1491" he knows your dessicator is missing.

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