03' AWM. As the name implies on this thread. I have just replaced the fuel filter on this car, following the instructions provided in the information board. Following the installation of the new filter....
I started my car, stalled out (as expected), started up on the second go.
Drove it down the street, stopped and check for leaks, noticed it was leaking.
Went back and retightened the clamps.
Stopped leaking. Turn off car.
Restart car. Let it sit at idle for 20 minutes.
Checked for leaks, none present, drove it.
Car feels as though it dies on the road, brakes function as if there is no hydraulic pressure.
Stumble back home after driving around the block.
Try to start it, really rough idle, engine does not sound healthy. After a period of time, blinking CEL light.
I'm at a loss. The filter is facing the correct direction. It's the correct part number.
I'd suspect that somehow you dislodged a vacuum hose or broke a check valve somewhere. The rough idle, lack of power brakes suggests that. I doubt the filter has anything to do with it.
I haven't touched anything on the engine. Only the two lines that go into the filter and out of the filter. Getting a blinking CEL light. Is the engine running rich or something? The coil packs are from the 2.0t, they're brand new and worked flawlessly before. Spark plugs are new too. Shouldn't be a problem there. It also has a brand new MAF. Checked the vacuum lines and nothing is out of place. Upon start the engine feels shakey, like it's not firing correctly. I'm in fear of damaging the timing belt.
What kind of check valves am i looking for? I took the new filter off, checked for obstructions in the lines going in and out of the filter, both were clean. Would re pressurizing the fuel lines make the engine shake and throw a code as it tries to get fuel in? Gonna try putting the old one on in a second.
There are plastic check valves in your vacuum lines under the hood. They tend to crack and come apart as they get older. Seems to be more of an issue on the 1.8T than the V6, but that may be just because there are more 1.8T's.
Did you remove the "new" filter and put the old back on? Try blowing air through the "new" filter, maybe? (It'll likely taste like shit.)
If you didn't change or manipulate anything other than the fuel filter; then I would start there with troubleshooting. I can't imagine that 'at that second' your fuel pressure regulator would go bad. Unless you were having problems previously.
Is there a chance that when you re-tightened the hose it wasn't fully on the filter flange? This might cause the line to be collapsed and cut the fuel supply? I'm guessing this is unlikely, just trying to think through the problem.
Did you remove the "new" filter and put the old back on? Try blowing air through the "new" filter, maybe? (It'll likely taste like shit.)
If you didn't change or manipulate anything other than the fuel filter; then I would start there with troubleshooting. I can't imagine that 'at that second' your fuel pressure regulator would go bad. Unless you were having problems previously.
Took it off, blew the air through it, out comes the fuel.
Nothing was wrong with car before I changed it. I followed all the steps, cranked the engine with the fuse out, replaced the filter tightened the clamps, placed the fuse in and started the car.
Could there have been an airlock, or air bubbles in your fuel line? I think that's unlikely but I'm certainly no expert.
I know it's frustrating but I'd swap the new one back on and see if it works this time.
Put the old filter back on, same issue. I can't see this being an air pocket issue. The car operated fine the first time I did it. It was only after returning home and tightening the clamp and letting it idle and taking a second drive did it start all this crap.
Do you have the protective panel on the rear? (You would have had to remove it to put on the filter.) Is there a chance you've pinched the hose at some point away from the filter?
Checked the hoses running in and out with a alcohol dipped screw driver, there are no obstructions for the 6 inches that thing can go in either direction. At this point the problem is under the hood. I'll need to scan the codes but I don't have a device to do so.
I think everyone is missing the significant clue: the loss of brake assist. If true, that has nothing to do with which way the filter is installed, the N80, pressure regulator, etc. If the description is correct, there is an air leak somewhere in the vicinity of the brake booster hose.
Could be because the engine is dying while in neutral or coasting. That could indicate a failure of correct fuel flowing to the engine. Not to mention no tampering has been done to the engine. There is no reason that those lines could have popped off.
OP, you need to be more specific. Is the brake problem only when the engine stops turning ?
You have a CEL there are fault codes. Without the codes we can only guess, what are the codes ?
Many shops will scan it free, or you can get a cable under $10 and free VCDS-Lite.
OKAY. Breakthrough. I was closely inspected the vacuum lines again around the brake booster as YLWagon suggested. I easily missed it at first but noticed that this was slightly off. Tugged it a little and viola it came free without any effort. Does this piece snap back together? I can't get it to by itself, is there a clip or a clamp that I'm missing?
You need to buy a new suction jet pump. You can try super gluing or epoxying the halves together in the meantime to drive it. That is causing your major vacuum leak.
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