austinado16

When we bought the car in June '06 the CEL was on for "EGR low flow." Of course this and 10 other major expense items had just been "taken care of" by the previous owner. Like everything else on the laundry list it was another job screwed up.

When I took the EGR Valve off the first time, the passage into the intake was packed solid and the compression fitting down where the EGR pipe meets the exhaust manifold was just missing...nice exhaust leak. I augered out and cleaned the passage, blasted out the intake with cans of carb cleaner, etc. Confirmed I had a working EGR valve and open passage, etc.

Still the EGR CEL has been plaging us. Today I took it all apart again. EGR valve still working and passage in the intake still clean and open. Even looking inside the intake through the throttle body looked pretty good (not that the runners aren't all gummed up, I'm sure.

What I did find during testing was a cloth braided vacuum hose up at the top of the intake, just next to the idle stabilizer valve, was rotted and had a hole completely through the side. Nice vacuum leak, right at the source of vacuum.

It took 7' of 3mm cloth braided vacuum hose to replace all of it. But now when I rev the hot engine the EGR solenoid ticks loud at first, and then tapers off to being quiet. Before, it would just sit and tick. With as much underhood work as I've done to this thing, you'd think I would have been smart enough to replace all of the ratty or marginal looking vacuum lines. Doh!

Waiting on an opportunity to go test drive on the freeway, and I'll report back on whether the CEL stays off.

Bmthorn

It's funny how much can go wrong with these cars because of the vacuum lines.

austinado16

Got no one to blame but myself on this one!

quattroaudi

Could you post some pictures of what lines you replaced? Where did you get the braided cloth vacuumm line from?

austinado16

3mm cloth braided vacuum line has been used on German cars for decades, so any shop that works on anything German will have a roll of it. It comes in a couple versions: Vacuum rated, and diesel fuel rated(with a yellow stripe).

I don't have any photos right now, but there are 3 main places.

1) Look under the Mass Air Flow Sensor (MAF) and you'll see the big bundle of them there that feed the EGR soleniod(tan one) and a black switching solenoid below it.

2) Take off the top engine plastic cover. Back in the right (passenger side) corner, right at the top.....in other words, just under the plastic cover.....you'll see a "Y" of 3 braided vacuum lines there.

3) With the engine cover off, back at the left rear (driver's side) of the engine you'll see 3 or 4 more long ones there.

4) There's one hidden one that comes out of the round plastic vacuum storage ball that's down below and to the right(passenger side) of the power steering pump. This one is sort of a bitch to do.

A word of warning!! Don't attempt to pull old vacuum lines off of old plastic fittings. You'll snap the fittings right off. Instead, take a sharp box cutter knife and slice the old vacuum line length-wise right where it's slipped onto the fitting. Once you've cut through, it will release and you can sort of bend it away from your cut. It'll open up at the cut, and come right off.

To install new vacuum lines, spray the fitting, and inside the end of the line with WD-40 and then slip the new vacuum line onto the fitting. This will keep you from using force.....and snapping off a fitting.

vespascuta

Yep. . .

On mine, vacuum lines were culprit of non-working cruise control & egr cel (coupled with the solenoid).

You gotta figure these lines are in most cases 10+ years old and subjected to high temps--tricky thing is they can look perfectly OK and still be leaky.

islingtonaudi

The BMW hose is cheap and good, 3 ft. for $6. At your friendly dealer.

Bmthorn

Do you still have the part number?

austinado16

^Agreed!

austinado16

Then I popped the lines off at the manifold and fuel rail, put my fingers over them and blew again. Bingo.....there was my leaking rotted line.