Volkswagen puzzle


#1

New 2001 Beetle powered down as I was driving and stopped. Would start after a few minutes but kept doing the same thing. Shop changed out the fuel pump and catalytic converter (disintigrated). Paid $726.86 and drove away only to have the same thing happen within 15 minutes. Back to shop, who consulted VW. “Heat problem” pronounced and crank shaft sensor changed. No difference. Car drives or idles for about 10-15 minutes before shutting off. Please help.


#2

You need a new shop.

There’s not enough information here to guess what the problem is, but a fuel delivery problem is not rocket science to diagnose and resolve. Your car has OBDII, which should send the tech in the right direction.

The “heat problem” that probably caused your cat converter to disintegrate (the ceramic substrate, actually) may have been caused by lean operation. Lean operation = hot cylinders, and that could have got your cat substrate glowing. Lean operation couold also have led to the shutdown.

The root cause could be a bad sensor. The signals from every sensor on that car can be analyzed on a scope to find out what’s bad.

It’s also possible that your tank can’t breath. The gas tank draws in air through a charcoal bed to replace the gas as it’s pumped out. If that line is kinked or clogged, as soon as the airspace in the tank develops enough vacuum the pump may not be able t maintain fuel pressre against the vacuum. Again, that should have stored a fault code.

You may also have an ignition system component that’s become sensitive to underhood heat. Anything with a wire coil should be suspect. That includes relays and the igniter.

In short, a good shop should be able to diagnose this one. Everything I’ve mentioned can be tested for. Heck, the mechanic could simply let the engine die out and see if you’ve lost spark or fuel.


#3

I certainly appreciate the advice. I take it from what you have suggested that the shop should be able to run a diagnostic history from what is on the car’s “computer”. I do not know if this has been done. I am looking at taking it to another shop. Thank you.