CitiGolf keeps switching off
I DRIVE a VW CitiGolf Chico, 2002 model, with the 1,4-litre engine, carburettor-equipped. Lately I have noticed a few problems:
(1) Sometimes the car just "dies" on the road while I'm driving. I am not sure whether it cuts off petrol or if this is an electrical problem. If I wait a few minutes it will start again and I can continue with my journey. Two mechanics suggested that I change the petrol pump (in front), but the problem intermittently persists.
(2) Sometimes when I hit the clutch the rev counter goes up as though I am accelerating.
(3) The fan only emits hot air, even when the heater is switched off.
Any help in diagnosing these problems. And advice about fixing them, will be much appreciated. - Brian Mathato
BRIAN, in a way you are fortunate to have a car that uses older technology where everything is relatively straightforward and mostly fixable by the owner. Let's look at your problems one by one.
(1) The most likely explanation for the symptoms of mysteriously dying while you are driving and then restarting a few minutes later, is occasional fuel blockage, which clears by itself when the engine stalls.
This can be caused by a piece of dirt or foreign matter being sucked up against an opening, blocking fuel flow, and then, when the suction is off, gravitating away from the opening to allow fuel to go through again.
I suggest that you systematically check all the places in the fuel-supply path where this can happen - the jets inside the carburettor float chamber, the T-piece where the fuel return line branches off, the in-line fuel filter and the mesh strainer on the pick-up pipe inside the fuel tank.
Other possibilities are a blocked tank vent valve, which causes a partial vacuum to build up in the tank, and, as you mention, the spectre of an intermittent electrical fault, which can be the very devil to track down.
Years ago, my daily transport was a motorcycle which did exactly what your Chico is doing. What was more, it chose its random moments of sudden death to occur, often when I was turning into an intersection. This led to some hair-raising experiences.
Like you, I tried everything I could think of to find the problem. Eventually, after months of fruitless searching and probing, I called Derick, a pal of mine who was a motorcycle mechanic by trade and who owned the same make of bike. He took my bike to their workshop, where, a few days later, I found Derick seething with frustration because he couldn't find out why the bike was doing this. In the end, though, he did succeed: One of the electrical wires going from the handlebars to the ignition unit under the seat had a problem. The wire looked absolutely fine from the outside. No kink and the insulation in perfect condition, but it turned out there was a fracture in the thin strands of copper wire on the inside, probably from when the wire was manufactured.
Normally, with the handlebars in the straight-ahead position, the broken strands would still make enough contact for the current to go through. But when the handlebars were turned, the wiring loom would flex and inside this particular wire the copper strands would move slightly apart, enough to break the connection sometimes. I still have that 100mm length of white wire that Derick cut out to insert a good piece. I hung it above my workbench to remind me of the tricks that a motor vehicle can throw at you.
(2) This sounds like sticky accelerator linkage. Check that the butterfly valve in the carburettor snaps shut, promptly and quickly, as soon as you lift your foot from the accelerator.
(3) This is almost certainly a case of the valve in the hose bringing hot water to the heater's little radiator not shutting off the flow completely when you switch out the heater. It could be due to play in the valve's actuating linkage (I suggest you check that first) or encrusted debris/corrosion inside the valve. Either way, it shouldn't be difficult to put right.