What did you do to your MKIV today?

[J_dude]

Car needs safety for new insurance, old car. Fine. Found cause of airbag light, was cut under passenger seat. Change a bunch of things. Almost done. Window doesn't go down. Motor good, switch good, regulator good. Must be the electrical motor control.

Where can i get one?

Seatbelt wire


what is the size of my computer screen

Nice Fluke btw

 

[burpod]

one interesting thing about n75 valves is they do actually need to be "upright". you can take it out of the bracket it's on, with car idling and vac gauge hooked up to the output barb. watch as the HG changes from upside to rightside up. if you shake it the readings will also bounce around

 

[Mozambiquer]

one interesting thing about n75 valves is they do actually need to be "upright". you can take it out of the bracket it's on, with car idling and vac gauge hooked up to the output barb. watch as the HG changes from upside to rightside up. if you shake it the readings will also bounce around

Thats good to know, especially for swaps.

 

[Taildragger03]

Replaced the oil cooler seals. The upper gave out yesterday some 365,000 miles and 20 years later. Replaced upper and lower. Highly recommend if you don’t know the history of yours.
VW part numbers:
038 117 070A Upper
038 117 070 Lower

 

[KrashDH]

20230131_145022.jpg

• Mozambiquer
• Feb 1, 2023

I don't have a mk4 right now, but here's what I did for an mk4 for a local vw shop. New 2 gauge alternator cable and I built a 120 amp alternator for them too.
Then not on a mk4, but very similar... was working on a b5.5 passat tdi and its been having boost problems for some time already. We replaced almost all of the hoses and replaced the camshaft, deleted balance shaft, just installed an almost new transmission and all... I took it for a drive after the transmission replacement and it didn't seem to boost right. I did the n75 test and it wasn't moving the actuator.
Okay, check vacuum, 30 in/hg so I pulled the n75 off... do you see what is wrong?

20230128_211930.jpg

• Mozambiquer
• Feb 1, 2023

why do people still use these Chinese pieces of junk! Not the first time I have seen this either. The n75 valve was really warm too. New pierburg on the way.

I've got 2 new Pierburgs sitting at my house that did not perform as well as the OEM N75 (Audi/VW). Wasn't stoked to find that out...

 

[Mozambiquer]

I've got 2 new Pierburgs sitting at my house that did not perform as well as the OEM N75 (Audi/VW). Wasn't stoked to find that out...

Interesting. Because the oem ones I have seen also are marked pierburg.

 

[KrashDH]

Interesting. Because the oem ones I have seen also are marked pierburg.

Mine has the Audi rings. But there was definitely a difference in performance when I hooked all 3 to a vac gauge and ran the VCDS tests (and on the car too logging)

 

[IndigoBlueWagon]

Not really surprising that a 20 year old N75 would perform differently than a new one. Whether it's better or worse, who knows?

 

[Zak99b5]

Started it up at 0*F. Glow time was the longest I have ever seen (this is my second winter with the car, all gassers before) at about 10 seconds or so.

Thought about doing the glow again, but decided to save the battery for the starter motor. Battery is about 2 years old and has never given me problems. However, I don’t know how much the glow plugs consume, nor did I know how long I was going to be cranking. Given a good battery, is glowing for that long twice an issue with cranking power?

Anywhoo, started cranking her over. After four or five revolutions she started showing signs of life. Kept her cranking counting to ten in my head so I could let the starter rest, and as I was reaching the end it was started. Let off the starter while it ran on three cylinders for a few moments, then it evened out.

So, it started on the first try, which is good, but I’m not sure it really should have struggled as much as it did. OE starter, 233000 miles, Howe's treated fuel, timing was between middle and upper line when I did the TB about 13,000 miles ago. Haven’t done a compression test, but I do get 47-50 mpg spring through fall, a little less in winter.

 

[Fix_Until_Broke]

Zak99b5 - That's a "normal" cold start. I wouldn't be shy of cranking for 15 seconds either when it's that cold, remember the starter is also at 0F initially .

The glow plugs draw ~10A each. When it's -20F, the light stays on a lot longer. I do a 2nd glow cycle when it's -10F and below because it reduces cranking time to showing signs of life. Each car will be a bit different depending on starter, battery, battery cables, injectors, timing of both injection pump and camshaft, etc. so figure out what works best for your setup.

There are a lot of things you can do to improve cold starting
- Ground wires from the back of the starter motor directly to the battery
- Advance injection timing to a bit above the upper line
- Advance cam timing 1 flywheel tooth

 

[Zak99b5]

Thanks good to know that this is normal starting behavior. I’ve just read here in posts by people who get 55 mpg just driving the car to church on Sunday with their fat aunt and uncle in the car pulling a trailer that at ten below they just touch The key and the car is purring like a kitten.

Next start this cold, I’ll try the double glow.

 

[Fix_Until_Broke]

Many of those posts may have been when the car had 33k miles on it instead of 233k too - remember the newest of these cars are 20 years old now .

 

[P2B]

After four or five revolutions she started showing signs of life.

I have read here that the ECU wants to see a cranking speed of ~300 rpm before it injects fuel. If that's true I reckon signs of life after four or five revolutions at 0F is pretty darn good.

My ALHs take at least that many, followed by another 8-10 seconds or so of help from the starter before they are firing consistently enough to run.

 

[TrashtruckTDI]

Needed some practice so measured, modeled and printed a PLA replacement for the center console latch. The hinge broke going in. Will give abs plastic a try next.

 

[norbert77]

Zak99b5 - That's a "normal" cold start. I wouldn't be shy of cranking for 15 seconds either when it's that cold, remember the starter is also at 0F initially .

The glow plugs draw ~10A each. When it's -20F, the light stays on a lot longer. I do a 2nd glow cycle when it's -10F and below because it reduces cranking time to showing signs of life. Each car will be a bit different depending on starter, battery, battery cables, injectors, timing of both injection pump and camshaft, etc. so figure out what works best for your setup.

There are a lot of things you can do to improve cold starting
- Ground wires from the back of the starter motor directly to the battery
- Advance injection timing to a bit above the upper line
- Advance cam timing 1 flywheel tooth

Advance cam? I just got the parts for a TB job, is advanced better year round?

Any list of pros and cons to cam or ip pump advance?

 

[Fix_Until_Broke]

In general terms - advancing cam to crank timing will favor lower RPM performance, below ~2500 RPM. Retarding will favor higher RPM performance.

Cranking compression is higher (therefore better cold starting) with the cam advanced as shown below. ALH is a stock ALH cam, C2 is the Colt Stage 2 Cam.

I'm told (no data) that the default injection timing is set mechanically within the pump (makes sense...). When the starter is turning the engine over, it's "at rest" position is what determines when fuel is injected during cranking since there isn't enough RPM yet for the internal pump inside the injection pump to control injection timing. Setting it a bit over the max line in VCDS may help cold starting. I've done it on my car and others and it doesn't seem to hurt anything, but can't say that it helps, but on the surface, the concept makes sense.

While looking for the above picture, I found the "Ground wires off the back of the starter" pictures...below is the most relevant one. You can see that the ground path within the starter has a lot of opportunity for poor connections. I added a pair of 10 AWG wires under each of the long screws that hold the back plate on and ran them directly to the ground side of the battery.

More details in this thread...

Battery seems dead, but isn't?

before you go buying parts, get a darn multimeter Please read the OP's description of what is happening. I believe that the battery is fine. Ours, with the same symptom, is fine after a new starter was installed...

forums.tdiclub.com

 

[braddies]

Pulled the rear lightbulb trays and found a bit of corrosion in the left side one, everything's been working except reverse lights (intermittently)
Gonna try cleaning this up enough to last a few more years

 

[JDSwan87]

Disconnect the tray from the wires prior to cleaning or you'll have a few blown fuses. Also, a battery terminal post cleaning tool works great for this task. Then a light coat of dielectric grease on the bulb upon installation...

 

[norbert77]

^^^ dremel with a carbon steel wire wheel

 

[braddies]

^^^ dremel with a carbon steel wire wheel

That's the next step, pencil erraser with mag/aluminum polish worked (a little bit) but only made it look like shiny corrosion

 

[norbert77]

That's the next step, pencil erraser with mag/aluminum polish worked but only made it look like shiny corrosion

I'd be worried about the film left behind

 

[Zak99b5]

Yesterday when I locked my car (key in the door), the alarm horn didn't sound. Blinking light came on, though. Made sure all the other doors were shut (which they were), but still no honk.

When I got to work the morning, I locked the car to test (never lock it at work). It honked just fine.

Fast forward to getting home this afternoon, and again no honk. Huh??

Micro switches all seem perfectly fine, as all the doors behave as they should with lights and whatnot.

 

[KrashDH]

Micro switches all seem perfectly fine

You sure about this?
The only time I didn't hear a honk when was these were bad ie the car computer thought the door was still open, so that's when it doesn't honk.

The only other time this happens is during the delay my Golf hatch stays unlocked for. There is a period of time it will stay unlocked before it auto locks.

 

[hey_allen]

I've had mine not honk when I've managed to unlock the trunk but it's still sitting closed, a couple of times.

Accidental trunk release button presses, I'm guessing.

 

[Vwkaferman]

Woot! Replaced the hood (alarm) switch. Alarm has progressively been randomly getting worse, going off at odd hours. Pretty sure I used VCDS correctly, was reading hood open when it was closed. So far so good!

Now I gotta replace the driver side switch and or the whole lock. Interior lights never come on with driver door, car arms.

James

 

[Zak99b5]

You sure about this?
The only time I didn't hear a honk when was these were bad ie the car computer thought the door was still open, so that's when it doesn't honk.

The only other time this happens is during the delay my Golf hatch stays unlocked for. There is a period of time it will stay unlocked before it auto locks.

Pretty sure.

This morning the lock behaved as expected--turned on the lights when I turned the key in the cylinder. Blinking alarm light went out. After I closed the door & put the key in the ignition, the interior lights went out. I opened the door as a test before starting, and the lights came on along with the door ajar light on the dash; both went out when I closed it.

After I arrived at work, I locked the car again as a test. No honk again. No other door or anything has been opened or shut since the alarm armed normally the last time--I'm the only one in and out of the car, and I didn't pop the hood, trunk, or gas lid even.

Would VCDS help with this? I'm not all that fluent in it.

 

[IndigoBlueWagon]

I had this problem in my Wagon a few years ago. I replaced the door lock module, didn't help. Turns out the comfort module was failing. Try and find a comfort module for an '02 Wagon with crank windows. Not easy. Dealer was willing to red label me one from Germany. I'm sure it's gone obsolete by now.

 

[Zak99b5]

Everything else is working, and it's not like I really need the honk lol, so I may just let this ride. It's just a weird thing. I'll be on the lookout for future problems.

Question--should the door ajar light be on when I open the door immediately after unlocking and before I insert the key into the ignition? I noticed today that I only got the door ajar light when the key was in, not before when I first got in.

 

[csstevej]

VCDS would definitely help you to figure out which switch is the issue.
On my car that’s how it works…..as soon as door is opened light is on before key is put into ignition.

 

[Zak99b5]

VCDS would definitely help you to figure out which switch is the issue.
On my car that’s how it works…..as soon as door is opened light is on before key is put into ignition.

Interior light, or interior light AND the door ajar light on the dash?