2002 Jetta ALH does not restart after running for 15 minutes or longer

[rustman1984]

Have you tried to remove the solenoid shut valve from the IP, ground its outside with the control wire connected to see if it opens with the 9.7V? If it were to open at that voltage, would that rule out that as a culprit? Also, I wonder if that 9.7V at warmer Ts is normal?

 

[tryin2vw]

If the engine has run for about 15 minutes, the engine will not restart. If the 109 relay is immediately replaced with a spare, the engine will immediately restart. I have (3) 109 relays that can be swapped, but have only been using two for these tests.

I have cleaned the following grounds: On the battery, (2) under the battery, (1) on the manual transmission, (1) in front of the ECU, and (1) near the relays by the steering column.

This may be unrelated, but I also noticed the MAF requested at idle is ~270 and if the accelerator pedal has not been moved recently, it will say the actual is 450 on my VCDS. Press the accelerator pedal and the actual and requested go back to being approximately equal.

 

[oilhammer]

That MAF behavior is normal, because the EGR turns off after it idles for a few minutes. Then once you rev the engine, it goes back to being duty cycled on.

 

[jmodge]

If the engine has run for about 15 minutes, the engine will not restart. If the 109 relay is immediately replaced with a spare, the engine will immediately restart. I have (3) 109 relays that can be swapped, but have only been using two for these tests.

I have cleaned the following grounds: On the battery, (2) under the battery, (1) on the manual transmission, (1) in front of the ECU, and (1) near the relays by the steering column.

This may be unrelated, but I also noticed the MAF requested at idle is ~270 and if the accelerator pedal has not been moved recently, it will say the actual is 450 on my VCDS. Press the accelerator pedal and the actual and requested go back to being approximately equal.

I haven't read this whole thread, so if I missed it......Are you are reusing the same 109 relays, just rotating them? If so have you ever tried unplugging one and reinserting it?
I'm wondering if there is a bad connection in the relay socket. I've found the backside of one burnt in a truck once. The operator had continuous HVAC fan issues. When parts were replaced it took care of the issue temporarily.

 

[jmodge]

A loose connection was arcing, iirc, the tangs holding the female connecter in the socket had collapsed. It didn't push all the way hrough the back, so it still made a connection, just not fully.

 

[tryin2vw]

A loose connection was arcing, iirc, the tangs holding the female connecter in the socket had collapsed. It didn't push all the way hrough the back, so it still made a connection, just not fully.

I am agreeing on a bad connection. I can swap relays or reuse the same relay, just the act of removing and reseating the relay will allow the vehicle to restart when the problem is occurring.

I believe I have narrowed it down to the blue wire on the back of the 109 Relay. A jumper was used to run the vehicle connecting the 4.0 RO and BL wires, eliminating the 109 relay. When it would not start, I pulled and replaced the RO end, still no start. I pulled and replace the BL end and started up no problem.

I have removed the back of the purple relay base. How does one get the connector out of the base? ( I will either alter the connector or replace it if the problem is in the wire back from the female terminal.)

 

[T1MMBOJONES]

try unplugging the coolant temp sensor when the car is hot and see if it still has the issue

and be very carful to not undo the little retension clip in the process. it can be messy, i heard from a guy

 

[tryin2vw]

and be very carful to not undo the little retention clip in the process. it can be messy, i heard from a guy

The coolant temperature sensor seems to function correctly.

 

[jmodge]

I am agreeing on a bad connection. I can swap relays or reuse the same relay, just the act of removing and reseating the relay will allow the vehicle to restart when the problem is occurring.

I believe I have narrowed it down to the blue wire on the back of the 109 Relay. A jumper was used to run the vehicle connecting the 4.0 RO and BL wires, eliminating the 109 relay. When it would not start, I pulled and replaced the RO end, still no start. I pulled and replace the BL end and started up no problem.

I have removed the back of the purple relay base. How does one get the connector out of the base? ( I will either alter the connector or replace it if the problem is in the wire back from the female terminal.)

I think it would be like defining any type of connector, it was on the truck. The arcing was evident from the backside in that case.

 

[jmodge]

depinning, auto spell strikes again

 

[tryin2vw]

To close out this thread, the blue and red wire terminals to the 109 relay were marginal. It would be ok when the vehicle was first started, but after running, it would heat up and not make solid electrical contact causing the voltage drop seen. Once the connections were made secure, there have been no issues starting the vehicle since. The 109 relay is also not getting warm or hot.

 

[rustman1984]

To close out this thread, the blue and red wire terminals to the 109 relay were marginal. It would be ok when the vehicle was first started, but after running, it would heat up and not make solid electrical contact causing the voltage drop seen. Once the connections were made secure, there have been no issues starting the vehicle since. The 109 relay is also not getting warm or hot.

I am also having a crank no start. On my sedan while running, the voltage at the solenoid shut off valve is 13.3V. On the wagon no start while cranking, the voltage is at 8-9V. I am not sure if cranking volts is supposed to be different or not. Since you had a hot no start condition, I'm trying to see if anything you did could apply to my scenario.

 

[tryin2vw]

I am also having a crank no start. On my sedan while running, the voltage at the solenoid shut off valve is 13.3V. On the wagon no start while cranking, the voltage is at 8-9V. I am not sure if cranking volts is supposed to be different or not. Since you had a hot no start condition, I'm trying to see if anything you did could apply to my scenario.

Is Relay 109 getting warm or hot (if the wagon runs)? I ended up crimping/smashing the female spade connectors on the Relay to ensure good contact. Also, Relay 109 can become worn out, so for $23 it can easily be replaced first.

 

[P2B]

for $23 it can easily be replaced

Twice

Relay 109 (A4)(B4)(A3)

Relay 109 is the main power supply relay for A3/B4, and A4 TDIs with the ALH engine. When it fails the engine will crank but not start. Sometimes they fail intermittently. Most TDI owners like to k...

www.idparts.com

 

[rustman1984]

Is Relay 109 getting warm or hot (if the wagon runs)? I ended up crimping/smashing the female spade connectors on the Relay to ensure good contact. Also, Relay 109 can become worn out, so for $23 it can easily be replaced first.

Do you mean that you crimped down the relay 109 socket spade connectors?

 

[tryin2vw]

Do you mean that you crimped down the relay 109 socket spade connectors?

Testing:
A jumper can be connected from the battery +(positive) post to the fuel shutoff valve on the IP to test the problem. Please do not leave it installed after testing as it will run down your battery in about an hour. (An uninsulated ring terminal was put on the fuel cutoff connection to make this connection convenient during repeated testing)

If the vehicle starts, then try: A jumper can be run between the brown and blue wires which should energize the fuel shutoff valve and allow the IP to work. There is not much amperage required for the test, so an 18 gauge wire and (2) 1/4" male spade terminals were used for my test. Again, it is not recommended to leave the jumper in the long term, the fuel needs to turn off when the ignition is powered down.

This is what I did: First, the relay socket/base was removed from the holder, position 12. Then the female spade terminals were removed from the relay base for the blue and brown (large, 4.0mm2 diameter) wires. The wires were installed on a relay and then "smashed" male/female together to make a better connection that did not easily come apart. Then the system was reassembled.

 

[rustman1984]

Testing:
A jumper can be connected from the battery +(positive) post to the fuel shutoff valve on the IP to test the problem. Please do not leave it installed after testing as it will run down your battery in about an hour. (An uninsulated ring terminal was put on the fuel cutoff connection to make this connection convenient during repeated testing)

If the vehicle starts, then try: A jumper can be run between the brown and blue wires which should energize the fuel shutoff valve and allow the IP to work. There is not much amperage required for the test, so an 18 gauge wire and (2) 1/4" male spade terminals were used for my test. Again, it is not recommended to leave the jumper in the long term, the fuel needs to turn off when the ignition is powered down.

This is what I did: First, the relay socket/base was removed from the holder, position 12. Then the female spade terminals were removed from the relay base for the blue and brown (large, 4.0mm2 diameter) wires. The wires were installed on a relay and then "smashed" male/female together to make a better connection that did not easily come apart. Then the system was reassembled.

Thanks for the steps.
Just to clarify on the first point, you are saying to jump the pos battery terminal to the IP shutoff valve and then crank to see if it starts?
On the second point, after jumping, crank to see if it starts?

 

[dcjkrueger]

Just a wild guess, but replace the crankshaft position sensor. My 03' Jetta did the same thing. Drove me crazy for a year before I finally hit on it. Car would not send a code indicating the the CPS was acting up. Solved my problem. Not expensive or hard to do.

 

[tryin2vw]

Thanks for the steps.
Just to clarify on the first point, you are saying to jump the pos battery terminal to the IP shutoff valve and then crank to see if it starts?
On the second point, after jumping, crank to see if it starts?

Yes.

The crank position sensor on my car was functioning properly.

 

[rustman1984]

Yes.

The crank position sensor on my car was functioning properly.

After recharging the battery and rebleeding the injectors, I got it to start. It has a rough idle though so on that next. Thanks for your input.

 

[bennybenben]

Just a wild guess, but replace the crankshaft position sensor. My 03' Jetta did the same thing. Drove me crazy for a year before I finally hit on it. Car would not send a code indicating the the CPS was acting up. Solved my problem. Not expensive or hard to do.

So I'm getting ready to replace my Crankshaft Position Sensor but I know there are a few gaskets along the process that needs to be replaced. Do you or anyone know what gaskets needs replacing?

 

[tryin2vw]

So I'm getting ready to replace my Crankshaft Position Sensor but I know there are a few gaskets along the process that needs to be replaced. Do you or anyone know what gaskets needs replacing?

I am not sure where the CPS is on a 2015. Usually it is just an o-ring.

 

[bennybenben]

I am not sure where the CPS is on a 2015. Usually it is just an o-ring.

Thank you good sir