Direct Injection question

eh? where'd you get this idea?

i think you need to get your facts straight before pursuing underinformed speculative tangents.

Reply to
jim beam
Loading thread data ...

Oil dilution seems to be inherent to some D.I. engines. My question is this. What path does the gas take to get to the oil pan? Through the cylinders as unburied gas, or leakage around the high pressure pump, or something I'm not considering?

Reply to
Fred

It's not inherent, it's a side effect of more than one manufacturer running their system much too rich in an an attempt to meet US NOx emission requirements.

For at least one model engine I know of, using the European version of the ECU software with their fuel map causes the oil diution issues to go away (and the gas mileage and performance are probably improved as well).

--scott (who drove the car with the Solex carbs to work this morning)

Reply to
Scott Dorsey

The real issue w/ DI cars that I've seen - and I have one, and am thinking that I may need to address this - is that because there's no fuel washing the back of the intake valves, the backsides of the intake valves are far more likely to get all sorts of carbon deposits on them, and there's no "pour it in the tank" cleaner that will get rid of them. The fix is to pull the intake and walnut blast the valves and ports. The "real" fix is to install a catch can in the PCV line to limit the oil in the intake to the amount that seeps past the valve seals.

nate

Reply to
Nate Nagel

The issue with _your_ DI car is that the high pressure DI pump fails prematurely because it was underengineered.

The fix is to go to BMW Excluservice in Rockville and buy the poor lonely E28 that they have for sale.

--scott

Reply to
Scott Dorsey

Nate Nagel wrote in news: snipped-for-privacy@news4.newsguy.com:

So? Why does that matter?

In the continuous pursuit of ever-vanishingly-tiny gains in safety, mileage, and emissions, cars are increasingly becoming laboratory experiments rather than practical utensils.

Direct-injection is just one more angels-on-the-head-of-a-pin theory brought to life. It's expensive, it's complicated, it's impractical. And...so what? It allows the politicans, activists, and bureaucrats to indulge their onanistic fantasies of doing nice things for Mother Gaia, and at /your/ expense. What more is required?

Reply to
Tegger

you're right that it's political, but you're wrong [as usual] about the [real] activists and their intent - in this case, they're working /for/ the oilco's, not against them.

back in the 70's, car manufacturers were [successfully] introducing lean burn vehicles [remember the honda cvcc tegger?] that offered considerably better fuel consumption, and this was a big business model threat that the oilco's took personally, and set out to kill. by [brilliantly] getting NOx emissions onto the environmental statute books, car manufacturers have been stuck with stoichiometric combustion and thus much higher gas consumption than lean burn.

the battle continues. NOx emissions statues aren't going to get repealed any time soon. but with d.i., you can burn a region of stoichiometric mixture within the cylinder where the fuel is delivered and richest, and the rest is basically just fresh air and doesn't contribute to excess NOx in the way that a full cylinder of lean mixture would. it's a very smart [and low cost to manufacture] means by which to achieve better economy while still complying with the convoluted and unrealistic emissions regulations that are designed to keep cars sucking gas like the behemoths of yesteryear.

Reply to
jim beam

as usual, you're full of it. #1 cause of intake valve deposits are hot valves causing the fuel that is directly sprayed onto them [and its heavier constituents] to carbonize. just like that black crust on your cast iron frying pan is caused by carbonization. "washing" only works if there is a gross excess of fuel, which there isn't after the engine has warmed up, and a high detergent content.

for you to be getting deposits means:

  1. your engine is "puffing" back because of valve timing overlap and a motor being used with too wide throttle at too low rpm,
  2. you're using cheap crappy fuel,
  3. because it's just a worn out piece of crap.

since 2 and 3 are right in your wheelhouse, and we know you're generally incompetent, i'd say you're "lugging" the vehicle, and having a problem with 1 as well.

3/3's not bad for an idiot monday.
Reply to
jim beam

I've heard that but it seems that either a) I got a good one or b) it was mostly resolved by 2009 as mine as of today now has something like

73K miles on it on the original HPFP and still pulls like a freight train (I put something like 700 miles on it over the past few days, and I can't count the number of times I hit and blew past the 80 MPH warning chime that I set - primarily to keep me pork friendly in VA - while passing other motorists on 2-lane roads. A simple tip of the right foot and it gets to Ludicrous Speed quite smartly, even in top gear...) I do have a Cobb AccessPort and can therefore check for "shadow codes" and will keep an eye on them, but so far (touch wood)

Ah, but then I'd have to Work On It Myself, which would defeat the purpose of buying the thing in the first place. I just wanted a car that I could enjoy driving that I didn't actually have to build myself for once. I think that I've already knocked out all the required maintenance save for I probably ought to replace the spark plugs (just got the special thinwall deep socket in the mail the other day) go ahead and add the catch can, and change the gear oil in the transmixer and rear end. And the navigation needs to be updated, but I was waiting for the 2013 updates to come out (they just did.) Other than that, it's, well, 100% functional. I suppose I could wax it.

That, and I'm fundamentally a coupe sort of guy. I would trade the new hauler in a second for a nice 3.0CS(whatever) as bad an idea as that would be from a practicality standpoint.

nate

Reply to
Nate Nagel

That describes the vague nagging feeling I've had looking for a used rig that I couldn't put my finger on; every newer make and model seems to be a beta version.

Thanks. -----

- gpsman.

Reply to
gpsman

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.