on the suggestion of a fellow f'chatter that i post this in the 328 section here goes: i recently had the oil analyzed from my 328 by blackstone labs. my sample was 10w-30 brad penn partial synthetic racing oil with <3000mi. there findings were measurable copper wear and significant fuel dilution along with viscosity thinning. last year i used castrol 10w-40 syntec with no issues and the same number of miles. any thoughts on the fuel dilution?
. If 'fuel dilution' means rich, then maybe, as the cold start injector's function in life is to squirt fuel into a cold engine for x seconds during start. If it squirts into hot engine or for longer than it's supposed to, the mixture will be rich. A malfunction results in warm start issues.
Bill, if they have never been updated, you probably still have the original Bosch steel injectors. Rather than fix them, go ahead and update/replace them with the current Bosch brass ones. The are not terribly expensive, perhaps $35 each or so. I did this on my 328 (many years ago, when you could pick up the injectors for $19 each!) and noticed significantly improved performance above 5000rpm. When later tested, my tech told me (if I remember correctly) that one injector was leaking, and at least two or three had poor patterns.
Forgive me if this sounds overly simplistic, but could he not have shown a fuel dilution problem if the shop had not run the car long enough before draining the oil? Say they started it to move it to the lift and then shut it off....... George
thanks guys for the response. gabriella is scheduled for her 3yr. majori this month. my plans were to change the injectors and cohine hose as well. btw the shop that changes my oil is also in my basement.(no lift either) and yes, i just ran her long enough to check out a few items before i changed the oil. i ran her to just bring the fans on and then shut her off. listen after the horrible winter we had, i couldn't wait to start her up. a bad temptation i know.
Probably not. 90% of the time if there is fuel dilution it is from one or more cylinders getting fuel but not firing or fuel being introduced when the motor is not running. CIS maintains considerable fuel pressure after shut down with a substantial quantity of fuel. The injectors are supposed to shut and maintain an absolute seal at shut down. Bad injectors often leak and allow that fuel to dribble into the motor. It eventually makes its way past the rings into the crankcase.
