Injector leaking ?

Hi,

My 318i E30 from 1989 suffers from very poor mileage (MPG).
My 530i is even driving more miles per gallon.

I think it might be a leaking injector, but I thought I'd first ask you.
These are the symptoms:

* Very rough idling like it's running on 3 cylinders
* Cylinder 1 (front of car side) seems to be the culprit, if I remove the high tension cable from cylinder 1's spark plug I don't notice any change in idling, while removing any of the other cables from the spark plugs makes a major difference
* The spark from the high tension cable for cylinder 1 is good enough
* Very poor MPG
* Above 2000 RPM there is no more sign of bad running, below there is
* Power output is very close to what a 318i should do

Could it be as simple as a leaking injector for cylinder 1 ? Or do these symptoms make you think it's something else.

If it's a leaking injector, is the problem in the injector itself or might it be caused by some broken seal ?

Thanks,

Ed,
The Netherlands

Ed,
Check the wires leading to the injectors, the copper inside tends to break due to wear and vibrations during the years. Had the same problem with my 325 i E30. Try to move the wires, if the engine picks up while moving them, you've found your problem.

Good luck.

Thanks Jose, I'll give it a try. But could that also be the cause of the low MPG ?

If the 1 st cilinder only picks up from 2000 rpm on, this could very well be the causing the low mpg as the other three cilinder are operating under much more strain to compensate the powerloss under 2000 rpm of the 1st cilinder, which means lower mpg as the other three need more fuel to obtain simialar bhp output as with four full functional cilinders. I guess the fuel milage will be oke after sorting out the first injector.

i'd take a sniff of the exhaust once your car is up to operating temperature, and see if you smell gas. also, feel your dipstick oil as well as smelling it. from my personal experience, even a short period of incomplete combustion (3 or 4 minutes) dumps a notable amount of gas in my oil.

sparkplug lead could be breaking down under load try another lead u know is good