Golf 4 TDI won't start? No error codes!

Hello everyone,

I drive a Golf 4 TDI, 66 kW, first registration 02/1999, with an ALH engine, and it has approximately 95,000 km on the odometer.
In April 2003, I had my 90,000-mile service.
I use biodiesel from May to November, and regular diesel for the other half of the year.

On Saturday, September 27th, I tried to start my car, but it wouldn't start.

I have observed the following:
- The car starts normally, with the engine making its usual sound.
- The tank is half full.
- The idle speed is just reaching 200 RPM.
- The battery is sufficiently charged, but jump-starting didn't work.
- Replacing the fuel filter didn't solve the problem. Before replacing it, there was no fuel in the return hose (which is transparent)!
- Accelerating does not produce any engine noise; the engine remains at its 200 RPM.
- Despite multiple attempts (at least five or six times), no success.

The car had been parked unused in the carport for two days. Before the last trip, it exhibited the symptoms described above, but it started normally on the third attempt. During the trip, nothing unusual was observed. The warm start before the drive home (city driving) was normal, just like the drive itself.

Since Tuesday morning, a certified automotive mechanic has been searching for the cause of the problem. When he checked the error memory, he found no entries. According to him, the battery and fuel filter are in good condition after his inspection.

He is checking to see if there is a defect in the common rail injection pump caused by the use of biodiesel. This has not yet been confirmed.

I would appreciate any further suggestions or experiences regarding what the possible cause might be!

Sure, here's the translation:

'Thank you in advance.'
Danny9

1. Search function, and there's a troubleshooting guide available.

2. If a mechanic needs 2 days to figure out why a TDI engine won't start, they don't deserve the title of "master."

3. I hope you filled the new diesel filter with fuel before installation?

4. When starting the engine/if it's misfiring, does fuel leak out from the loosened retaining nuts on the fuel injectors? (Caution: Please hold the injector securely with a wrench and avoid twisting the fuel line when tightening.)

Yes:
- Are the valve timings, timing belt, tensioner, etc. all in good condition?
- Does the engine have compression?

No:
- Voltage at the shut-off valve of the fuel injection pump?
- When playing the organ, does the fuel come directly from the return line of the injection pump (the return line between the injection pump and the diesel filter)?

Okay, let's hear it...

Best regards, Rainer.

Hello C.C.K!

There should be a solenoid valve on your fuel pump that controls whether fuel enters the pump or not. Try to determine if this valve is working properly.

2. Check if your fuel pump relay is receiving power.



I hope this helps you.

2. Check if your fuel pump relay is receiving power.


VP37 engines (including the ALH) don't have that.


- Replacing the fuel filter didn't solve the problem. Before replacing it, there was no fuel in the return hose (which is transparent)!

This is giving me something to think about.

One argument against using biodiesel is that RME (Rapeseed Methyl Ester) can damage seals on the one hand, and on the other hand, its solvency can clog pipes and filters. This can then cause the pump to draw in air and fail.
Therefore, this could be a potential cause of the error. In addition to all the other issues that using RME can bring about...

CU Gremlin.

So, I can tell you that I've driven approximately 70,000 km using biodiesel, and I haven't had any problems.

'No leaks detected, but the fuel consumption was about 0.2 liters higher, and the performance was slightly reduced. However, the fact that I would pay €0.69 for diesel versus €0.45 for biodiesel gives me pause, aside from the environmental considerations.'

Best regards, Mike.



-
One argument against using biodiesel is that RME (Rapeseed Methyl Ester) can damage seals on the one hand, and on the other hand, its solvency can clog pipes and filters. This can then cause the pump to draw in air and fail.
Therefore, this could be a potential cause of the error. In addition to all the other issues that using RME can bring about...

CU Gremlin

Hi,

Then I should probably move somewhere else, as the price of a liter of diesel in the Hamburg area ranges from €0.79 to €0.85.

Ja das ist richtig... nicht nur Diesel, auch ersatzteile... LMM approximately 130 euros.

However, the cars themselves cost at least 10-20% more than they do in Germany.

Best regards, Mike.



Hi,

Then I should probably move somewhere else; in the Hamburg area, a liter of diesel costs between €0.79 and €0.85.

My colleague Mike is from Austria, that's why diesel is so cheap there!

Hello,

'I have a neighbor who, after 20,000 km using RME fuel in their AFN engine, needed new seals for the ESP (Exhaust Gas Recirculation) system. The seals themselves are relatively inexpensive, but the removal, installation, and replacement of the seals at Bosch cost a total of €900 (unfortunately, the car has over 100,000 km, so there was no warranty coverage).'

Bosch has confirmed in writing that the RME was the cause, and Audi has also given its approval, but still, no payment has been made.

I have the old seals, which are porous on one side, as well as the invoices and responses from Audi.

She called me back then because her car wouldn't start either. However, the reason was that the pump couldn't build up any pressure internally because the fuel was leaking out of the pump as it was being drawn in. The car had to be towed to the workshop.

According to their own statements, the Bosch service center here seals approximately 1 ESP (Electronic Stability Program) module per week.

Incidentally, one of the reasons given for rejecting the goodwill request was the claim that we had the ESP repaired at an external workshop (i.e., a Bosch service center).
My subsequent letter, in which I stated that Audi workshops are not capable of repairing the pump due to a lack of know-how and equipment, has not received a response.

@Ulf & Rainer, would you like a copy of the invoices for the forum?

Bertil wrote:

My colleague Mike is from Austria, that's why diesel is so cheap there!

I somehow probably deleted my post instead of editing it -- sorry .

... thank you for your answers!

I'll keep you updated on what the error was!

@ Rainer K.
I filled the fuel filter with diesel after installing it!

See you soon.
Danny9

garth.brooks wrote:

@Ulf & Rainer, would you like a copy of the invoices for the forum?

Hi Garth,

I leave the decision to Rainer, as the host .

Hello Garth,

Thanks for the offer, but it's nothing really new, which is typical for biodiesel production...

Best regards, Rainer.

Rainer K. wrote:

Thank you for the offer, but it's not really anything new, as is often the case with biodiesel...

Hi Rainer,

That is, of course, correct.

But for most people, "documents" make a stronger impression than texts that "simply appear somewhere in a forum."

In other words: If we could display something here, with a description like this...
"You too could receive such bills and letters if you drive a car powered by biodiesel and something goes wrong"
... then, in my opinion, it would have a greater impact and likely trigger more "preventive discussions" between customers, Bosch, and VAG.

Therefore, I would support the publication.
But of course, I also respect it if you don't want to get involved in any trouble.

Hello fellow thinkers,

I am mobile again!

The suspicion of a faulty fuel distribution pump has been confirmed!

The repair was carried out by a VW workshop.

Volkswagen subsequently received invoices and complaints, with urgent requests for full coverage of costs – otherwise, they risk losing me as a customer.

Today I received a reply stating that they will process the case as quickly as possible.

I will keep you updated.

Your Danny9.

Hmm, as far as I know, the return hose isn't transparent. The transparent one is the supply hose.
If diesel fuel is not reaching that location, then the cause could be leaks or the need to replace the fuel filter.
Furthermore, I'm surprised by the 200 RPM reading; the engine doesn't even start at that speed. I suspect the starter motor is failing (possibly the brushes), or more likely, the battery has lost its capacity and the starter can only manage around 200 RPM. However, the ALH engine needs at least 300 RPM. Have the battery capacity checked.