new bmw owner - 316 compact fuel starvation?

[Barwick]

What is the likely cause of this, fuel starvation is my guess - it's an M reg 316 compact and the engine seems to idle nice and pulls really well, it's actually farely nippy and a nice drive for a 1600 I think but now and then more often than not when giving it some welly it splutters really sharp like and you momentarily lose all throttle for a second and the car judders then.

If it was the air flow sensor it wouldn't idle well would it if that was on it's way out? It doesn't cut out and stall the engine at idle like the air flow sensor would cause it to do like on one thread I just read on here more like a fuel starvation feeling.

I figured it's likely to be the fuel filter? if not maybe the fuel pump (really don't want it to be that had enough fun changing an in tank pump for one lifetime on different car).

Could it be the fuel pressure regulator? Would low pressure cause that effect?

So far i've replaced the spark plugs, checked the compression (all consistent 8.2) and stuck a timing light on it.

It's also overheating at the moment but the compression is good and theirs no metal flakes in the oil so the internals are probably alright. Where is the thermostats on these things? only had the car a few days. I just read in the haynes manual a trick on how to test it with boiling water so I want to get it off see if its that causing it. Sounds farely simple to test. If that's fine what else could it be ? Checked the radiator and that's not blocked atall. Seemed like one half was hot and the other was cold the other day when it was overheating which made me think it was blocked but it seems fine after testing.

thanks sam

[Barwick]

the beast:

[thekid]

The first problem does sound like a fuel problem. Either injectors, filter or pump. Run some fuel treatment/injector cleaner through it. If that doesn't work, replace filter then pump, or both at the same time if you really want.

The second problem, assuming that your cars plastic propellor has already been changed to a metal one, it is most likely a faulty thermostat.

[Barwick]

I think it's plastic the viscous fan, do you lot advice taking metal ones from something else to use? how is that better than a plastic one at cooling?


I'll give that cleaner a go, i've already squirted wd40 and some carb vleaner whilst running the engine down the carbs which hasn't fixed it. Is that carb cleaner the stuff you mean?

fuel filters are pretty cheap ain't they? seem to only be around 7 quid on eBay.

[thekid]

I was reffering to the plastic fan in your water pump. Depending on what year your car is (I can't remember the cutoff date for the plastic fan) you will either have a plastic or metal fan in your water pump. The plastic fan blade will break thereby causing your car to over heat. Also pieces of plastic might make their way through to other parts if left alone. However, I think it is most likely a broken thermostat. It is the first thing any mechanic replaces when a car comes in over heating. I think pelican parts might have a DIY for replacing the thermostat. Also chances are, that the plastic propellor if your car had one, has already broken and been repalced hopefully with a metal one.

For the cleaner, I am not sure what brands you have on your side of the big puddle, but 44k is a great fuel injector/fuel system cleaner. It comes in a can and you just pour it in. They have another that you direct inject into you r fuel injectors, you don't want that one. If the cleaner doesn't work, then you would want to start looking at your fuel filter and pump.