G3 TDI: Power Loss Troubleshooting

Hello!

I'm having the following problem with my Golf 3 TDI, engine code: 1Z, year of manufacture: 1993, mileage: 156,000 km.
I believe he lost performance wearing the suit, but especially in terms of top speed!
'Maximum 2 weeks, ideally no more than 140. Lately, I've been up to 160 again on the weekends, but...'
Not exactly thrilling!

Error reading revealed:
fuel injection start regulation difference (sporadic)
- Error cleared, took the S-Bahn (suburban train), and I was back!
- Injection start timing adjusted, but nothing has changed!
- Tank and fuel lines cleaned, but no improvement!
- Needle penetration tested by tapping... okay!

Next week, I want to test the pre-lift pump by installing an additional pump between the fuel filter and the pump... Would that fix the problem if it's the pump that's causing it?

What else could I test/try? I'm so lost and don't know what to do anymore...

I've already swapped the LMM with a used one, but there wasn't a 'significant' change.
According to Bosch customer service, the current LMM (lambda measuring module) is providing the correct values.
Unfortunately, I won't be able to get the VAG-COM until the end of next week at the earliest.

TDI_Butze wrote:

Next week, I wanted to test the pre-lift pump by installing an additional pump between the fuel filter and the pump... would it fix the problem if it's the pump causing it???

"Pre-injection pump? On a 1Z? Well, my 1Z G3 from MJ96 didn't have a pre-injection pump, and I don't know of any 1Z that did. Or did the early 1Z models have one? The VP37 usually doesn't require a pre-injection pump either."

Hello,

Have you checked all of this already?
Search term: "Error codes" under "TDI Error/Knowledge Databases".

Error code: 550.
Injection start control, pressure difference.

Possible causes:
Fuel injection timing valve (N108) defective.
Needle feed mechanism (G80) malfunction.
Fuel tank emptied.
Fuel supply not working correctly.
Fuel shortage.
Air in the fuel system.
Funding start not as planned.
Fuel filter clogged.
Fuel leaks.

Hello,

Perhaps he is referring to the impeller in the electric water pump (ESP).
I suspect the issue might be related to air being sucked in, a clogged fuel filter, or a faulty fuel injector/wiring problem.

Best regards, Rainer.

He sucked in some air, but that seems to have disappeared with the fuel tank/fuel lines!
Is there still air pressure in the ESP? I have to drive a few kilometers before I can check!??
How can I test the fuel injector?

Genau die Pumpe meinte ich. Es hätte ja sein können das die Schaufeln verschlissen sind und so die Pumpe nicht mehr 'genug' Diesel zum einspritzen bekommt... !? Aok, ber.
The person who gave me the idea had already tested something similar on a TDI engine, and it worked for him...!?

@ Michael II
Yes, I have! Except for the fuel injection timing valve, I don't know how to test it.
And the needle movement was tested by tapping it; if it were defective, it should stop working, right?

TDI_Butze wrote:

Rainer K. wrote: ... maybe he's referring to the impeller in the ESP. ... That's exactly the pump I was talking about.

It could have been that the vanes were worn out, and therefore the pump wasn't getting "enough" diesel to inject... !?

Ah, that's good. So, if the ESP (wing cell pump) is defective, simply install a pre-feed pump and the problem is solved. } Well, that's a rather unusual repair method.

Okay, so...

Fuel injection start valve - N108, electrically test:

Disconnect the connector from the fuel injection pump.
Perform a resistance measurement between contacts 2 and 3.
Set Point: 12 ... 20 °C
If the target value is not reached, replace the fuel injection start valve (N108).

Check the voltage supply from the valve - N108.
Measure the voltage between contact 3 of the connector and the motor ground.
Set point: approximately equal to battery voltage.
If the target value is not reached, eliminate any line breaks or short circuits.

Check the control of valve N108.
Connect the diode test lamp to contacts 2 and 3 of the connector.
Perform actuator diagnosis and adjust the valve for injection timing.

When activating the valve for injection start, the LED test lamp should blink.
If the LED test lamp does not light up or remains constantly lit, the wiring connections should be checked for short circuits to either the positive or negative terminal, as well as for any breaks in the circuit.

Check the spray adjustment.

Perform actuator diagnosis and adjust the valve for injection timing.

When adjusting the injection timing valve, a noticeable change in the combustion sound should be audible (the injection timing adjuster will move back and forth between "late" and "early" settings).

Initiate the basic settings and select ad group 00.

The display in display field 2 must count up to 255.
40 255 0 20 90 201 64 153 127 83

If the target value is not reached, the injection restrictor in the injection pump is blocked.

Okay, thanks! @ michael II I'll test it out once I have the VAG-COM.
Okay, I'll measure the resistance and voltage tomorrow.

@ Bertil, the acquaintance who told me this apparently did it on a Passat TDI.
He just wanted to test it with me! He didn't want to repair it! I'm not going to install an extra pump on the train line!
The best thing to do would be to put a submersible pump in the tank *lol*.
No, that's not what I meant, it was just for testing!
If that had been the case, I would have had my ESP refurbished or replaced!

Hi,

It might still be okay for testing purposes.

Check the voltage supply from the valve - N108:

There are only 2.5V at terminal 3 relative to ground!
I once disconnected the connector from the control unit and measured the resistance of the cable... 0.14 ohms! So, there's no broken wire.

And what if there's a short circuit somewhere? Has something like this happened before?
If so, where...? It might save me some searching!

Thank you!

TDI_Butze wrote:

Check the voltage supply from the valve - N108: There are only 2.5V at terminal 3 relative to ground! I once unplugged the connector from the control unit and measured the resistance of the cable... 0.14 Ohms! So, there's no broken wire.

Hi.

Pin 3 of the 3-pin pump connector is the 12-volt wire, which is powered by relay 109 via an internal wiring harness splice.
If it's only receiving 2.5 volts, something is wrong.

Between which points did you measure the 0.14 Ohm resistance?

On the other hand, in this case, the tension is only used to delay the start of injection (at partial load and idle).
Under full load, the injection molding machine is usually almost current-free anyway, so this observation cannot initially explain the power loss.

It would be a different issue if the MSW also receives insufficient voltage (which is connected to the same wire/splice as the injection control valve).
Then, it may not be possible to raise the pump far enough, but this should, in my opinion, be reported as a serious error with a blinking indicator.

I measured the 0.14 ohms from the STG connector to pin 3 of the 8-pin pump connector.
According to the manual, pin 52 should be on the STG.

Well, I wanted to check if the cable had any defects... but it seems like it doesn't!
If the 2.5V is okay...

Okay, then I can't proceed until I have the interface set up.
Okay, I'll go through the other possible error scenarios now.

TDI_Butze wrote:

I measured the 0.14 ohms from the STG connector to pin 3 of the 8-pin pump connector. According to the documentation, pin 52 on the STG should be

.
Hi.
Okay, there are several things that are wrong here.
Pin 52 is the RWG input and has nothing to do with the injection volume adjuster.

Quote:

Well, I wanted to test if the cable had a defect somewhere... but apparently not! If the 2.5 V are okay...

2.5 volts instead of 12 volts are definitely not okay - if you measure at pin 3 of the 3-pin pump connector.
Pin 2 carries the injection timing signal, and a value of 2.5 volts is often considered normal for this signal (representing an effective or pulsed voltage).

Hmmm, according to my wiring diagram, the cable from pin 3 of the pump connector goes to pin 52 on the control unit... which also makes sense based on the 0.14 Ohm reading! I just wanted to check the cable! Here's my wiring diagram; I hope it's large enough!?

http://mitglied.lycos.de/butzesdiesel/golf/Schaltplan.jpg (The wire is marked 'red'.)

I measured at pin 3! I'll check it again just for fun...
Maybe I was wrong...

RWG-Eingang!? RWG = ?

'Sorry for asking what might seem like silly questions, but until a year ago, I only drove gasoline cars, and I find them to be much less complicated!'

TDI_Butze wrote:

Hmm, according to my wiring diagram, the cable from pin 3 of the pump connector goes to pin 52 on the control unit... which would also be consistent with the 0.14 Ohm reading! I just wanted to check the cable! Here's my wiring diagram; I hope it's large enough!?

Hi.
Your diagram shows the MSW (quantity setting device) and the RWG (regulating track selector).

If you write beforehand...

Quote:

Check the voltage supply from the valve - N108: There are only 2.5 V at terminal 3 with respect to ground!

. . . then you might have noticed that the N108 designation doesn't appear at all in this plan .

Quote:

Sorry for asking what might seem like silly questions, but until a year ago, I only drove gasoline cars, and I find them to be much less complicated!

Well, that's just the way it is with TDIs... but once you understand the basics, it gets easier .