Engine sputtering, not accelerating. Left for 20 mins and is now fine?

Question

The car is a Mk1 Golf (1993, 1.8lt, mechanical injection).

I was driving up a medium incline and suddenly my car starting sputtering and I lost acceleration. I pulled over and started the engine again to listen. I checked the air intake and boot for leaks, there were none. Fuses were fine. Fuel levels were OK - about 1/2 a tank. Tempreture was fine - its warm here and I had already been driving fro about 30 mins. There did seem to be a distinct whining coming from the fuel pump though. Every time I started the engine it would run for a little bit then sputter out.

I rang a friend who brought tools but when he arrived and started the car again it was fine. I was able to drive home (5 mins) with no issues. The fuel pump even sounded fine again.

The plugs and fuel filter are only about 6 months old, so I dont think its them.

Would anyone know what could have caused this?

A theory I have is that maybe some crap in the fuel tank got caught in the lifer pump filter and temporarily blocked the fuel lines. Possible?

Answer 1

Your Golf should have two fuel pumps: one for the injectors (high pressure) and one which feeds the injector pump (low pressure). The low pressure pump would reside in the fuel tank. I'm thinking the low pressure pump may be going bad, as in getting weak. If it were starting to overheat, it may not pump fuel like it is supposed to and would cause the loss of engine power and allow the car to start sputtering and behaving poorly. Once you let it sit for the 20 minutes, it cooled down completely and was able to work for the five minute drive home. The only way (I can think of) to check this is to put a fuel pressure gauge on the input fuel line to the injector pump and read the pressure while it is behaving as you described. You'd have to see what the pressure reading was prior to any problem, then what it was when acting up. This may be hard to accomplish, because a failing fuel pump may work just fine one minute, work intermittently (or poorly) the next, and may just fail outright some time near in the future after that.