rough idle and hard to start when hot

bimmer1990325i · 03-24-2004, 05:20 AM

I have a 1990 325i with 130,000 miles. Recently tuned car and replaced wires, rotor and cap. Also replaced timing belt and tensioner. Bought this car used last year; no maintenance record was provided.
At traffic light stops there is a slightly rough idle and once the car is warmed up enough it seems as though it might stall but it doesn’t. After driving for a while, around 1 hour, if I park the car and turn it off and go to start it back up again, it is very hard to start. Reminds me of the old flooded carburetor days. Any ideas, recommendations would be appreciated.

Jared at Pelican Parts · 03-24-2004, 06:21 AM

I would check either the fuel injectors, fuel pressure regulator or the fuel filter.

In fact I'd replace the fuel filter and see if it makes ant difference..

bimmer1990325i · 03-24-2004, 07:37 AM

Thanks for responding.

Is the fuel filter easy to replace and easy to get to in order to replace?

wludavid · wludavid's Garage

The fuel filter is near the driver's side rear wheelwell. Really easy to get to and change - don't even have to remove anything (except maybe a wheel) to get to it! I'd recommend aslo getting the proper size hose and some OEM hose clamps from your local dealer. The filter itself is cheap:

http://www.pelicanparts.com/bmw/catalog/shopcart/BE30/POR_BE30_fuelij_pg4.htm#item25

rgarling · 03-29-2004, 07:13 AM

"Reminds me of the old flooded carburetor days. Any ideas, recommendations would be appreciated."

I think that is exactly what is happening to you. One (or more) of your injectors is not closing all the way, and fuel is leaking down into your intake manifold flooding the engine. Since this leakdown is a function of time (more time, more fuel), you can make sure this is the problem fairly easily by getting your engine warmed up and running correctly, then turning it off. Try to restart immediately. It should restart easily. Wait longer, the problem should manifest. If so, leakdown is the problem. You can try fuel injector cleaner, but it probably won't work.

if the car can sit for a while, remove the injectors and send them off for a rebuild. Take a look at www.cruizinperformance.com. Otherwise, buy new ones and sell off the old ones to someone for cheap.