Solenoid Valve N109 VP37

Hi,

I replaced the engine block in a 1Z and transferred all the attached components, including the ESP, from the defective block to the new one.
Unfortunately, the engine won't start, but that seems logical to me, as error code 1237 is displayed.

I directly connected the N109 to 12V, but I hear nothing.
Then I unscrewed the valve, but unfortunately, the plunger is still stuck in the ESP!
[Image]
The black valve stem on the left side of the image is what is being referred to.

I can't get the punch out of the ESP with my fingers, but I haven't used any tools (like pliers) yet.

Is it normal for the plunger to get stuck?

When the device is fully assembled and 12V is applied to the N109 (with the housing connected to ground), nothing happens. Is the N109 therefore defective?

Regards,
Jens.

Jens 16syncro wrote:

Is it normal for the plunger to get stuck?

No...

Jens 16syncro wrote:

When fully assembled, there are still no 12V at N109 (with the housing connected to ground), and nothing happens. Is N109 therefore defective?

Yes.

I just pulled the punch out with a pair of pliers; it wasn't really stuck in there that tightly, it came out pretty easily.

I left the impact wrench outside and reattached the N109 and reconnected the cable.

The engine actually started, but unfortunately, only twice for a second .

The immobilizer is working, so that's not the problem. VCDS would also report it.
Now, error code 1269 has appeared, which indicates a N108 interruption or short circuit.

Would the engine actually start, despite error code 1269?

Quote:

Is it normal for the plunger to get stuck?

This can happen when the O-ring is holding the valve stem in place. It's often difficult to remove it on your own, especially with greasy fingers.

Quote:

The immobilizer is working, so that's not the issue. VCDS would also report it. Now, error code 1269 has appeared, which indicates N108 - interruption/short circuit.

Valve for injection start. Check the wiring harness, especially the connector for the injection start valve. It's quite possible that you have a loose connection somewhere that causes problems when the engine starts.

Does the control unit reliably provide +12V on terminal 15?

The valve also has a 7.5A fuse next to the MSTG (presumably a motor starting device). You might be able to measure continuity from there to the pump and check if there is still voltage at the pump.
Best regards,

klahaui wrote:

The valve also has a 7.5A fuse next to the MSTG.

Do you mean the N109? I can take a look at that, yes.
However, I'm surprised that the N109 is supposed to be protected with a 7.5A fuse, considering that the cable in the car's wiring harness has a cross-sectional area of only 0.5mm² (Passat, year 1997).

When you turn on the ignition, should there always be 12V on the wire leading to the N109? I measured it, and unfortunately, there was no voltage present.

Looking at the components of the N109, it seems that when 12V is applied, the plunger should be pulled into the valve's tube, and when 12V is not present, the internal spring should push the plunger to the "closed" position.
When I was disassembling my N109, the plunger was still inside the ESP. That means my attempt to apply an external 12V and expect a reaction was probably futile.

So, if I apply 12V to the modified N109 with the plunger attached (with the housing connected to ground), the plunger should be drawn into the tube. I'll try that tonight.

vwSchrauber wrote:

Check the wiring harness and especially the connector for the VE. It's quite possible that you have a loose connection somewhere that causes problems when the engine starts.

I have an older ESP installed with the 8-pin round connector (for the interlocking system) and an additional 3-pin connector.
Both N108 and N109 run through the three-way connection.
However, I've examined the connector at least five times and measured the three cables, and I can't find any faults.
But you're right, this connection seems highly "suspicious." I'll re-evaluate the test scenario.

I mean the fuel injector, not the shut-off valve.
Best regards,

The problem isn't with the idle cut-off valve, as you've already removed it. A fault in the control of the injection timing would cause the injection timing to advance excessively after the engine starts (due to the missing 12V), but not within one second.
Is the valve properly installed and sealed?
hg
Herbert.

Well, at least it starts now...
Unfortunately, it doesn't run; it just briefly starts up and then shuts off after 1-2 seconds.

Quote:

Error 1269 N108: Interruption/Short circuit

is still there.

That probably matches the symptoms; it starts up, but the faulty connection to N108 causes it to shut down.

Can the N108 be measured? It only has two cables, are there any resistance values or similar?

By the way, I can't find the mentioned 7.5A fuse for the N108; where could it be located?
The cables in the car's wiring harness leading to the connector are all only 0.5 mm², while those leading to the ESP are 1.0 mm². That's quite a small cross-section if more than 5 amps are supposed to flow through them (7.5 amp fuse).

When I removed the engine, everything was fine, but now nothing works .

Quote:

Can the N108 be measured?

"The resistance value for an open circuit (cable disconnected) is infinite. A short circuit is 0 ohms (approximately 0.5 ohms with a cheap multimeter and connecting cables)."

"I don't have a 'correct' value for the resistance of the coil winding, but based on logic and how it works, I would expect something in the range of 10-30 ohms.

Quote:

That probably matches the symptoms; it starts up, but the faulty connection to N108 causes it to shut down.

No, that only creates an error entry on the 1Z.
The resistance value of N108 is 14-18 Ohms.
The N108 is protected, depending on the MSG, along with other valves and the mass flow meter.
Please check the following parameters with the ignition on and after the engine has started: MWB 1, 5, and 19.
Are you sure the immobilizer isn't interfering?
hg
Herbert.

Resistance value N108 is suitable, it's okay.
No through road to Masse.

I also tried connecting a different ESP (without installing it), but unfortunately, I got the same result: error codes 1237 and 1269.

"That tells me the problem isn't likely to be in the ESP (Electronic Stability Program) itself, but rather in the wiring harness or electrical system of the car body. However, I didn't touch anything in that area during the engine replacement."

I can access the immobilizer control unit using VCDS, and there are no error codes stored in the memory. Therefore, the problem is unlikely to be related to the immobilizer system.

Which pins on the MSG (Motor Steuergerät - Engine Control Unit) do the three cables for N108 and N109 connect to? I would disconnect the connector from the MSG and perform a continuity test to the connector in the engine compartment. (Assuming they actually connect directly to the MSG).

But somehow, I'm at the end of my rope .

Quote:

Which pins on the MSG do the three cables for N108 and N109 connect to?

It depends on the control unit. 1Z is not the same as 1Z. What kind of vehicle do you have, what is the year of manufacture, and what is the MSG part number?
It's possible that you damaged a cable during the renovation.
Was the fuel injection pump adjusted mechanically as specified?
Edit: Is the plunger of the shut-off valve still removed?
hg
Herbert.

Well, my MSG probably has a glitch .

It started with an old MSG (engine control unit) from an Audi 80 (without WFS). However, the MSG from the Audi cannot be used for driving; it's still a version intended for ESP (electronic stability program) with a potentiometer-based quantity control instead of HDK (hydraulic quantity control). The engine runs, but it's impossible to achieve anything other than a very irregular idle speed with it.
At least, this proves that the ESP (Electronic Stability Program) and the wiring harness are okay.

Let's see what happens next. I just lent out my spare MSG (monosodium glutamate), so I need to get it back first.

You shouldn't be surprised if you break something when you start swapping components like that. The pin assignments of one MSG (Module Control Unit) are often very different from another. How do you know what signals are supposed to go to the immobilizer contacts and what signals are supposed to go to the quantity control?
hg
Herbert.