BMW 525i e34 - starting problems if car not driven for a day

[AltaVDM]

Basically if the car is not driven for approximately one day then it has severe starting problems. Car will initially start but does not quite feel right - engine sounds flooded, car backfires and jerks.

Once parked and engine switched off, there is absolutely no way I can get that engine to start for at least an hour afterwards. The engine does not even attempt to turn when the key is turned.

After an hour, sometimes a little bit longer, then engine allows me to turn it on and I am able to drive. Sometimes the engine still feels a bit strained with the flooding and backfiring, but it is not as bad as the initial start-up and this usually goes away after it has stood for that hour.

When driven every day, the car is fine. It is only when it has stood for a while that it does this.

I would also like to mention that this car did stand for a few years before I bought it. And even after the purchase it was not an every-day car. Recently (I'd say for about a year now) I have had no option but to use it every day to work and that is how I have noticed the problem.

I am really stumped as to what it could be - any tips or advice? Anyone else experience this problem?

PS: 1989 model

Thanks guys,

 

[Donovan2412]

Have you given it a proper service since it's been standing?

 

[Fordkoppie]

Sounds like FPR
Or the non return valve of the pump
Or leaky injectors

 

[JayDrft]

Hi There,

Is the car by any chance using anything, like water or oil?

Also, could you mention which motor you have - I would assume an M20 motor due to year model, but you do get the newer type multivalve engines(Wide tappet cover).

Im speculating here - but it might even be a corroded water port in the head, that may be seaping water into the combustion chambers/cylinders, hence the back firing and battling to start, cause we all know water doesnt burn well at all.

Where are you based, there are a couple of spot checks you can do to try and narrow the search down.

Give us more info, and we can take it from there.