Golf 3 TDI: Won't Start? Troubleshooting Guide

Hi.

It's about a friend's Volkswagen Golf.

Volkswagen Golf 3 TDI, engine 1Z, first registration 09/1994, mileage 240,000 km.

It also features a factory-installed anti-theft system (RDW) with an integrated immobilizer, located beneath the light switch. It does not use a transponder-based immobilizer.

The car ran perfectly for a distance of 100 km, then it simply stopped working. However, after a few minutes, it started again, allowing the remaining 50 km to be covered.

Then she parked the car, and three days later, when she wanted to drive home, it wouldn't start again; it just made a sputtering noise and then stopped.

"At the location, I tried to see if diesel was reaching the injectors when starting, but nothing came out. I used starting fluid in the intake manifold, and the engine started briefly but then died once the fluid was burned. I only tested that once, which isn't ideal."

We picked up the car yesterday, and today I checked and exchanged a few things.

Timing belt alignment is correct.

Diesel filter replaced, system bled using a hand pump connected in between.

In addition to trying to feed "rescue diesel" into the injection pump via infusion, nothing happened, and despite attempts to bleed the injectors, no diesel is reaching them.

The magnetic valve on the VP37 clicks when the ignition is turned on.

I bypassed the anti-theft alarm system.

Relay 109 is audibly clicking; it has been replaced with a new one, but there is no change.

Ignition switch replaced, no improvement.

Error memory (read with existing VAG 1551) is, of course, empty.

I'm a bit stuck right now. The girl who owns the Golf is in training, so she doesn't have much money. Buying something like a fuel injection pump or an engine control unit is simply beyond her budget.

Here's my question: Does the VP37 provide enough power to activate the energized magnetic valve, or does the engine control unit also send a signal to it?

What is the most effective way for me to proceed?

Thank you, Rüdi.

Hello Ruedi,

Quote:

Startpilot checked for proper installation in the intake manifold

.
Please don't, the engine might break.

Let's see if...
- the diesel injection pump receives...
- The return hose on the ESP should be transparent and filled with diesel. A small air bubble is acceptable, but larger bubbles or foam indicate a problem, as the pump is drawing in air instead of diesel.
- Diesel filter and connections checked?

Without control signals from the engine control unit (ECU), the engine will not start.

I would remove and inspect the control valve, and use a diagnostic tool to observe the starting process, specifically checking the fuel injection quantity in measurement block 1.

Does your diagnostic tool, "Autoscan," work properly?

Best regards, Rainer.

Quote:

First, a question from me: Is the VP37 sufficient to power the energized magnetic valve to start it, or does it also receive a signal from the engine control unit?

Sure, of course.

The anti-theft alarm system is a common problem in the Golf 3. Usually, the cause is cold solder joints. It's questionable whether they can be easily bypassed.

I would like to take a closer look at the anti-theft system.

Hello Rainer,

The thing with the starter pilot was an attempt to test it on-site, but it was only for a short time, and it didn't work properly. I'm aware that this approach can do more harm than good.

As I mentioned before, I filled the fuel injection pump with diesel using a container and a tube to eliminate any air pockets or leaks, while also trying to bleed the system, but no diesel reached the injectors.

I only have an old VAG 1551 available.

Best regards, Rüdi.

"@Autoservice: Firstly, the anti-theft system appears to be working correctly. Secondly, I have bridged the corresponding connections. I still had the wiring diagram from RDW, as I had previously worked on a Golf 3 gasoline car with RDW that had cold solder joints."

@Rainer: Did you add anything else? I will check the thing about the shut-off valve and the corresponding part as soon as the rain stops, but unfortunately, the Golf is parked outside .

I'll get back to you later, but probably tomorrow.

I would start by checking the diagnostic system to see if the MSG (Multi-Shot Generator) is even attempting to inject.

"If there's a broken cable, it will never start, and you'll be searching endlessly. Potential culprits include the solder joints in the VP37, especially if they've been tampered with and resoldered before. Alternatively, it could be the wiring between the MSG (Material Signaling Device) and the quantity interlocking system. However, there are still so many possible causes that reading the error codes is a much simpler approach."

I'm not familiar with the VAS 1551, but I'm sure it can be used to read error codes and data blocks, right?

Just to be sure, the simplest question: Does the pilot light even turn on? (Probably it does, since you mentioned that the shut-off valve clicks). The basic DWA system only interrupts three things:
- Fuel pump (not applicable, as it is already filled externally).
- Starter motor (you would have noticed).
- and ignition signal (in which case the cutoff relay wouldn't click and the preheating indicator wouldn't illuminate).
That effectively eliminates the DWA option, leaving only MSW, MSG, and cabling.

Greetings.
Guste.

Okay, I was just at the car again, and it's raining a little less now.

"@Guste: The preheating light is working as it should. I'm now ruling out the glow plug relay, as it's bridged. Nothing has been modified on the car. It's just been a long time since it was in a workshop, so there's a backlog of maintenance (like the timing belt...), but that will be addressed only after the engine starts running again."

I removed the shut-off valve, took out the piston, and reinstalled it (if it starts, I'll need to shut it off). I also attached the 1551.

Engine speed during the start attempt 260 RPM.

Injection amount 51.0 mg/H

Voltage adjustment slider 0.800 V

Coolant temperature 8.1 °C

The next planned step, when it's dry outside again, is for me to open the cable harness covering near the starter to see if any individual wires are broken. I've encountered this issue twice before on a Passat 35i TDI, although in those cases, the error memory contained confusing entries.

The VP37 is either completely disabled (set to zero) OR the "stopper" is engaged, preventing it from starting.

If one person doesn't want to, nothing will happen.

I would first remove the support and reinstall it without the Koblen.

Always leave a loose jam nut on the nozzles during initial startup attempts.
At least diesel fuel needs to be involved if anything is going to happen.

I'm just wondering if, with good hearing, one should even be able to hear the MSW (Main Switching Unit) working. Especially if the parking brake is engaged.

If that is the case, absolute silence is an indication of a dead MSW.


m;

@dieselmartin: Our posts overlapped.

As you can read above, I have already installed the fuel injector without the piston, and one fuel line is disconnected to see if anything happens when starting, but so far, there's not even a drop.

Unfortunately, my hearing is too damaged to hear anything from the MSW (presumably a radio signal). I need to check when my wife gets back to see what time it is transmitted, or if I can use the 1551 (likely a radio) to tune into it.

Hi,
Check MWB 019 when the ignition is on, and MWB 001 during the start-up attempt.
Do you see anything happening when you try to start it (values 2 and 3 need to increase in steps)?
hg
Herbert.

According to my information (1551), the MWB 019 does not exist; it stops at 013.

The value of 2 in MWB 1 jumps from 0 to 29.8 and then slowly increases to 51.0.

The value of 3 remains unchanged at 0.800V.

Edit: I've connected this 1551 times to my AFN, and it's showing the MWB 019 code there.
It's not due to my equipment.

When the value reaches 2, the quantity adjuster should be activated; this is the desired injection amount. Value 3 is the feedback from the control valve, and it seems to be stuck in the idle state.
It's a shame you can't read MWB 19, as it probably still has an MSA12 module installed (which is typical for 1994).
The most likely culprit would be the throttle valve. Listen to see if it moves from stop to stop when it's activated. Is there anything stored in the error memory (e.g., 00765)?
It's likely that you'll only be able to proceed by removing the cover of the ESP and taking a look inside.
The cable to the pump is fine, and so are the connectors?
hg
Herbert.

Error memory is empty.

I'm going to have someone with better hearing go on a listening tour tomorrow, first to compare with my own AFN (audiometer), and then to listen to Patient 1Z.

"And then I'll tackle the wiring harness in the engine compartment, all the way to the VP37. Hopefully, it won't rain, because I unfortunately don't have a dry place to store this unexpected item."

Thanks for getting this far. I'll get back to you tomorrow when I know more.

Here are some additional things you can do: check the resistance and power supply of the pump. On the round connector (on the pump side):
- Setting knobs (#4 and #7): 0.4 - 1.1 Ohms.
- Rule sliders (#1 and #3, #2 and #3): 4.9 - 7.5 Ohms;
dto, from the control unit, ignition on:
- #7 against mass: Battery voltage;
- Approximately 2.5V for both positive and negative terminals relative to ground.
hg
Herbert.

Quote:

The likely culprit would be the throttle valve. Listen to see if it moves from stop to stop when it's activated. Is there anything in the error memory (00765?)? Probably, you only make progress if you remove the cover of the ESP and take a look.

Remove the cover, turn on the ignition. The control slide must move from the zero position to the full position and back. Then, it is set to an intermediate value (starting amount).

If you're willing to risk a small amount of diesel leaking, you can start the engine while observing what the fuel regulator is doing. This is useful because the engine control unit (ECU) might not be receiving enough voltage during startup to set the fuel injection quantity to the starting level.

Hi.

I performed the measurements that Herbert recommended, and there were some discrepancies in the resistance measurements, specifically on my AFN. However, the values were roughly equivalent to those of the 1Z.

Okay, so my wife put her ear to the ESP (Electronic Stability Program module), and first on my AFN (engine code), she heard a humming sound when the ignition was turned on. On the 1Z (engine code), she only heard a short clicking sound.

I then examined the wiring harness and, lo and behold, a broken wire leading to the ESP system was staring back at me. It was corroded and broken, so I temporarily fixed it, and the engine is now running.

It was definitely a strong contender for me, right alongside the DWA and the Relais 109.

I will also examine the other wires and, if necessary, solder in sections and insulate them with heat-shrink tubing.

Thank you for your help so far.

Rüdi.

Great, thanks for the feedback!

What surprises me is: There is almost certainly a corresponding error code entry in the error memory in such a case. Are you sure that your diagnostic tool displays all errors?