My Golf 4 ALH won't start anymore.

Hello!

My Golf 4, ALH engine, manufactured in 1998, with 308,000 km on the odometer, stopped working today.

Background: I would describe the car as absolutely reliable and trouble-free so far, based on my experience of over 10 years and over 100,000 km.

There were some issues with the immobilizer, but that was probably due to a weak battery (causing the problem of difficulty starting when the engine is warm), and the reading coil seems to be weak. Once a week, I have to turn the ignition key and restart the engine, and then it works.

But this afternoon, the engine doesn't seem to want to start at all.
The engine doesn't make a single spark or any kind of noise.
Completely without warning, it was working perfectly normally yesterday.

What I have checked so far:

Oil and coolant levels are okay.
The timing belt is properly tensioned and is moving.
The tank is half full.
It doesn't appear to be the result of a weasel attack either.
I also have the impression that the engine is compressing, so it's not just spinning freely without any compression.

Then, get the laptop ready.
The engine control unit (ECU) indicates, as usual, "Engine control unit locked, intermittent."
Immobilizer problem.
The idle speed is being displayed, and after the numerous start attempts, it was 200 RPM, which was slightly higher before.

The immobilizer is located in the instrument cluster; the error message indicates a weak or intermittent key signal, and it has likely been there for a long time.

I deleted both errors, and they haven't reappeared.

Furthermore,
In the instrument cluster, the "start authorization" or "start permission" indicator sometimes flickered from 0 to 1 in increments of half a second.
I don't know if that's normal. I've never been that far before.

What I haven't done yet is disconnect a high-pressure fuel line to see if the injection pump is working.

I will do that first thing tomorrow.
I've also seen those electromechanical parking brakes, like the ones found in the Golf 1 and Golf 2.

It's been too long, I don't remember.
Can someone tell me how to test this device?

And I'd also appreciate any further suggestions you might have for what else I can do.

Has relay 109 already been replaced?

I experienced this in August with our 20-year-old Galaxy.

Hi,

The ALH is essentially a modern version of the 1Z engine. In my 1Z engine in my B4, the electric fuel shut-off valve failed after 315,000 km, while I was driving at 180 km/h on the highway. Deploying to the parking lot and troubleshooting.
You can quickly check the parking brake like this:

-Disconnect the connector from the parking brake actuator and, with the ignition turned on, use a test lamp to check if there is voltage present.
- Additionally, you can try inserting the plug into the flat contact of the power strip and see if you hear a click or if it switches.
Okay, bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

- To get it working again for now, you can disassemble it by removing the valve piston and spring, and then screwing the housing back on. Nothing else happens, but then it should start again.
So, I got it fixed and drove around like that for about a week.
You can still set the switch to the "stop" position, because the MSTG (Multiplex Signal Transmission Group) also retracts the point machine when the switch is set to the "stop" position.
The replacement part cost me about 40€ back then.
The adapter doesn't fit the older 1.6 diesel engines; they are smaller.

Regards, Mpire.

Hello!

Today, I spent some more time working on my problem child.

So, diesel fuel is not injected during the initial start-up attempt.
I once loosened a fitting on an injector.

I found relay 109, removed it, and took off the cap. Everything looks good, and it's also working.
I plugged it back in, but since this is a known issue, I'm going to install a new one on Monday.

Furthermore: Regarding the topic of "Absteller" (a German term, context needed for precise translation).
There is no voltage present when the ignition is on.
I didn't disconnect the cable, though. Simply measured the voltage against ground at the threaded connector.
That also worried me.
I didn't measure it during the startup attempt.

When I turn on the ignition, I notice something moving, clicking, or making a noise inside the fuel injection pump. It seems like that's the target.

The next step would be to figure out why nothing is arriving at the drop-off point.
I've traced the cable as far as I could, and there's continuity. The multi-plug also looks very verschandeln inside; I've opened it up before.

Sure, here's the translation:

"Addendum:"
I was just at the car again.
The cable from the dispenser has been disconnected.
When I apply 12V to the starter, it clicks loudly and the click is clearly felt.
However, when the ignition is turned on, nothing reaches the supply line.

Hi,
Let's try starting it with 12V at the cutoff point.
hg
Herbert.

Herbert wrote:

Hi, Let's try starting it with 12V at the cutoff point. hg Herbert

I just did that. No success.

Furthermore, I've checked all the fuses again, the ones that might be related to this issue, and everything seems to be fine.

Then I made some more room so I could get a better look at relay 109.
That definitely turns it on.


Okay, so I'll soon be nearing the end of my artistic endeavors.
I probably need to check if the road closure is working properly.
I think I saw something about a "start authorization" somewhere.
Can anyone give me some advice?
Sure, here's the translation:

"Any other suggestions?"

Hi,

If the diagnostic function for the engine control unit works during startup, the 109 also provides the necessary operating voltage for the engine control unit.
Based on my experience, WFS (Water Flow Sensor) problems are usually recorded in the engine control unit's fault memory.

Fuel injection must occur when the fuel shut-off valve is deactivated and the engine control unit grants the start signal, provided that fuel is actually being drawn in. It is possible that... Foam in the transparent hose leading to the ESP?

Best regards, Rainer.

Hi!

Sure, no problem.

I need to verschandeln the fuel hose properly first, but at first glance, I didn't see anything unusual.

Then, deactivate the locking mechanism, which means removing the spring and the striker, if I understand correctly .

And then I'll take another look at it calmly, using my laptop.

On the Sharan AFN '97, one out of two polarity pairs in the starter motor was defective, resulting in a starter motor speed that was too low for the starting release. Many years ago, there were increasingly more problems with warm starts, but it started up immediately when cold.

When it was completely failing, a new, inexpensive starter motor was installed, and it now starts perfectly again after 300,000 km, just like new.

A possible approach to pinpointing the error could be to initiate or start the process.

On the Sharan AFN '97, one out of two polarity pairs in the starter motor was defective, resulting in a starter motor speed that was too low for the starting release. Many years ago, there were increasingly more problems with cold starts, but it started up immediately when rolling or in a cold state.

When it was completely failing, a new, inexpensive starter motor was installed, and it now starts perfectly again after 300,000 km, despite the original injectors, and runs almost like new.

A possible approach to pinpointing the error could be to initiate or start the process.

Even if relay 109 switches, it doesn't necessarily mean that current is flowing through it. Usually, it has cold solder joints. In our case, they are barely visible with a magnifying glass. If this cold solder joint is in the area of the load contact, the relay can switch as much as it wants, but no current will flow through it.

The shut-off valve is only one component of the system that allows diesel to be released from the injection pump; the VP pump also receives a release signal from the engine control unit (ECU).

This whole situation reminds me of the Golf III TDI story, where there's a thread I started about it. In that case, there was a broken wire in the wiring harness leading to the VP37 pump, specifically in the starter motor area.

Hi!

Okay, there's some news from the workshop, although it's not good news:

So, I read the engine control unit and the instrument cluster again today, and yes, it indicates problems with the instrument cluster.
The same old mistakes are appearing again, the ones he's been making for the past 10 years. And yet, it still works. Therefore, I initially ignored all this electronics mumbo-jumbo and continued as the boss instructed.

Rainer mentioned that we should check the diesel line. I cleaned it, and normally you can always see an air bubble there.
It wasn't the case for me.
Okay, I checked the line, and it's empty. No diesel.

Then I started experimenting and put diesel into the ESP (Electrostatic Precipitator).
Regarding the influx, it's been quite a lot, and I've managed to process a good portion of it.

The engine then started after a bit of sputtering following the third attempt.
Then, when the engine started, I saw the misery.
The fuel injection pump is leaking badly; when the engine is running, diesel fuel is pouring out of it.
I didn't exactly see the leak, though.
However, it might be due to the connection between the steel part (where the high-pressure lines are screwed in) and the aluminum housing. Somewhere in the lower area that is not visible.
It must have happened on the day of the last trip, I didn't notice anything, and the car had been working perfectly fine up until that point.

That's when my ESP just ran out. Then, of course, it won't start.
Oh, what a mess.

The timing belt is less than a year old, and the car is otherwise in very good condition. I also have a long time left before the next vehicle inspection (TÜV).
I think I'll fix that.
I can install and remove the pump myself.
Also, I think it's also about the attitude. In case of an emergency, I may need to ask about this again.

In my opinion, it seems like it's going to be a used pump.

Or do you see a possibility of resealing it?
Or maybe just try tightening the screws?

Of course, this involves some work, but the gardening season is over, I can drive my T4 for now, I have all the necessary tools, and I can heat the garage.
Well, it's not a disaster for me. But it's also a bit of a nuisance.

Hi Steffen,
If the pump leaks externally, the leak is located in the low-pressure section.
Regardless, there's a Bosch gasket set that's supposed to contain (almost) everything.
The pump for my decommissioned 1Z had the part number 2 467 010 003-000.
You need to search for your pump's number on the Bosch website.
You can find the instructions here in the forum.
hg
Herbert.

There are two options at the back: either a triangular screw or a high-pressure block, where the fluid can leak out. The O-rings become hard and flattened.

In principle, you can replace it in the installed state. The ring of the triangular screw requires a special socket, and the HD part is tricky but doable. You need to pull it out far enough to remove the ring and then press in a new one. I successfully did this in the spring on an AFN, and it's been leak-proof ever since.

Hello!

I took a closer look at it today:
Okay, so first, I removed the injector pipes and the small bracket on the high-pressure side.
Everything was cleaned and observed. With a mirror and flashlight, as far as I could see.

Okay, if by "triangular screw" you mean the part in the middle of the fuel injection lines that connects to the pump, then yes, it's prone to leaking.
But it's not like large amounts of diesel are now leaking out of the engine when it's not running.
After 10 minutes, I could see it slowly seeping out from the inside of the threads.

If it says "160 bar" on it, then it looks different, of course.

But an explanation for why the pump ran dry in 24 hours, causing it not to start anymore, is probably not that. It wasn't even that much that would drip off in an hour.

I think I'll try to get the engine running again tomorrow, and then take a closer look. I'm now familiar with the suspicious areas.

The pump isn't drawing fuel properly; it's sucking in air, and the diesel is flowing back through the lines into the tank.

It's best to replace both seals at the same time. However, to install the HD part, you'll need longer screws so that the block can only be pulled back as far as necessary; two screws are sufficient.

Once it's too far out, the VP (vehicle) needs to be expanded and disassembled. With the AFN (family car), I had the advantage of having a VP37 stored away for any eventuality; it's not a mistake to have one for each of the 4 AFNs in the family.

Don't ask me about quantities; I have a vast and seemingly endless collection of screws and bolts from the automotive sector, and almost always something useful for improvising.