Vacuum leak help

[MEL744]

The PCV is integrated into the valve cover. See here for a diagram.
Membrane for valve cover VAG 06F103469D 2.0 FSI - Vanos BMW Repair kits for cars

[metako]

Thanks again MEL744. Wouldn't mind buying one of those PCV membranes - have you tried to buy one from their eBay store? Looks like they're in Russia.

[MEL744]

No problem, I haven't bought one, as far as I can tell the PCV system is operating normally on my car (could be wrong about that though). Have never tried to pry off the plastic cap either to have a look, might try it next time I am at the wreckers.

[metako]

Yes I think ours is still ok too but would be good to have as a spare in case it goes south in the future.Good idea to take one apart at the self-serve wreckers too.

[JustCruisn]

PCV is fed from crank up the hose on the left, and then back out the pipe on the right back to the intake.
If you wanted a catch can you would put in inline with either of those 2 lines.

[saabman]

Dont, I pulled my daughters out thinking it might be leaking. its REAL thin ended up putting my fat thumbs through the diaphragm. just looking at getting one from Vanos BMW at the moment - they are the only place I have seen them advertised

[metako]

Thanks for the info re the PCV valve routing Justcruisin. Well I've finally found the time to finish the repair and the hardest part was the crazy clic-R hose clips! I managed to reuse 5 but had to buy 3 new ones at $15 each bartered down from $20 each from VW (I could not find them anywhere else).

Turns out the clic-R pliers I bought were too thick (see attached pics) as I couldn't get them to close the clips, even though they opened the clips fine. These clips may be great for the robots assembling the car but for us humans they are a giant pain. I tried to find regular hose clamps to fit but all of them were too wide to fit the rubber hoses.

Anyway, reassembled the intake manifold and smoke tested it again and everything was ok. Runs great now and rough idle gone. Thanks to Justcruisin and MEL744 for your valuable assistance.

[MEL744]

No problem, happy to help out! That's very annoying about the pliers not workings, those clips really are a pain! Would you mind sharing the link to the pliers you bought so we can know which ones to avoid?

[metako]

Sure - these ones:

7"/180mm Clic-R Collar Pliers Spring Loaded Hose Clip Clamp Latch Lock | eBay

[metako]

Well the Golf was fine for a week or two but then one morning my wife drove off in it only to come back a few minutes later saying the poor idle was back and she just made it back home. I started it up and it sounded and felt different this time - more like an ignition problem than a leaking vacuum problem. It was so bad it was undrivable.

After checking all electrical plugs and vacuum hoses were intact, I plugged in the Vagcom and all the old "Leak in Air Intake System" and "Random/Multiple Cylinder Misfire Detected" error codes were there. Realising I hadn't cleared the old codes after I fixed the intake rubbers, I cleared all codes and started the car up to get new codes.

After clearing the codes it suddenly ran beautifully!!! What??? How could clearing codes change the engine from undrivable to running perfectly? Has anyone ever heard of this? It happened too suddenly to be co-incidental and we had started the car many times across multiple days prior to this trying to diagnose the problem.

After a few days of running well it now will not even start - turns fine but doesn't engage. Charged the battery up and ran another Vag com scan and there are NO errors at all except for drivers headlight bulb which we know is blown. I've got a fair bit of diagnosing ahead of me but I thought the "running well after clearing fault codes" may be a clue to the problem. Any ideas?

[metako]

Forgot to mention that I did another smoke test and no vacuum leaks apparent this time.

[metako]

I had some time today to do some more testing. There is no spark at the plugs when cranking and when I probe the coil pack electrical plug there are 2 earths, a constant 12V and a voltage of only 0.08V on the ECU pin when cranking. Should there be higher voltage than this on the ECU pin?

Also I was going to pull the fuel hose off where it meets the fuel rail to test for flow but I could feel that the fuel hose was hard with fuel pressure so decided I didn't need to go any further. When I pulled the plugs after cranking there was no sign or smell of any fuel on them, so looks like I have no spark and no injectors firing. What could cause this? Is there an auto trans inhibitor switch on the MkV FSI which inhibits both spark and injectors and might be malfunctioning (but I guess it would just inhibit cranking)?

When I tested the A1 engine control relay it worked fine but the resistance across pins 86 and 85 was 170 ohm and everything I've read says it should be half this value. Could this be the problem?

[metako]

After reading this article Coil-On-Plug Technology and Diagnostics Tips | 2018-02-16 | Auto Service Professional which says that some cars will shut off ALL coils and injectors if the ECU detects a major misfire in ONE cylinder, I disconnected Nr 1 coil connector and cranked the engine and it started and ran on 3 cylinders! I reconnected coil Nr 1 and cranked again and it started and ran on all cylinders. Strange. So I figure there might be an intermittant fault possibly on cylinder Nr 1 either in the spark plugs, coil, coil connector/wiring/ECU. I replaced all the spark plugs as a start and if the misfire returns I'll replace the coils one by one starting with Nr 1. Then I'll start replacing the coil connectors etc.

I tested Nr 1 and Nr 2 coils on the bench with a 5V trigger and they both fire ok but this doesn't mean they don't have an intermittant misfire under compression of course. At the moment the car is running great with the new plugs. I didn't think to replace the plugs earlier due to the fact that I've never had a car fail to start due to plugs - misfire yes but not totally fail to start. I have never heard of the ECU turning off all coils and injectors due to a misfire in one cylinder, but this will be one of the first things I check in the future. It also expalins why I had fuel pressure in the rail but the spark plugs were dry after cranking.

[BirdManFJ]

Then I'll start replacing the coil connectors etc.

How easy/hard is it to replace the coil connectors? I assume you're talking about the leads to the coil packs? Last time I replaced my coil packs, I noticed the brittle plastics of the connectors had broken off in several places, and may be the cause of some mis-firing I have experienced.

[metako]

Yes those ones. I haven't done this on a Golf yet but I imagine its just a case of pushing a fine jewelers screwdriver into the connector at the right spot and de-pinning the old connector and pushing the pins into the new connector.