Car won't start troubleshooting

[delvey]

Is this correct?
I've cleared a load of fault codes and the car is trying to start.


Also, within VCDS when I try option 035 to test the fuel pump, I get an error

 

[AgentSpencer]

2011 Golf TDI M/T w/ 154K

Hard to start and will not idle; must idle up to 1000+ RPM in order for it to smooth out. Once you remove foot from gas, it dies. I bought the car from a guy who stated it ran fine till it did not. It threw a Cylinder 3 misfire code, so he replaced injector with new OEM. Did not fix the issue. Smokes slightly when running.

I have double checked the timing which is dead on (he replaced the timing belt approx 3 months prior to issues starting). Fuel delivery from tank and supplemental pump is strong. All injectors are coded correctly per OBDeleven module. There is no metal in filter or HPFP.

What's crazy is how smooth it runs above 1000 RPM. Running out of ideas as to what the culprit might be. Thanks in advance for any help!

 

[Mark G]

Is the fuel filter fairly new?

 

[AgentSpencer]

Is the fuel filter fairly new?

Brand new...

 

[danielru]

Hey, im a sort of a newbie but interested in fixing some things myself. I have a 2008 vw passat b6 1.9tdi 77kw and the engine when engine is cold (after a night, temperature at night between 10°C and 20°C) does not start.
A bit more details about not starting:

• In the morning, when I want to start the car, it often times starts and then imediatly (runs for like a second or two) shuts off, unless I give it a quick rev.
• When trying to start again, engine cranks, but doesnt start.
• After cranking for about 3-5 seconds, on dashboard pops up a warning smth like this: "Engine off! Oil pressure" and it beeps constantly.
• If I ignore the warning and keep cranking, eventually, after like 10-15 seconds engine starts.
• I put in a new battery recently (like last week), it got rid of the problem for a week, but today this stuff happened again.
• When the engine warms up a bit, after driving, if I shut the engine off, later in the day, this does not happen, unless engine cools off again and sits for a longer period of time.
• I got the computer scanned, it showed me a P0642 Sensor Reference Voltage A Circuit Low and P161A and P161B - glow plug cylinder 1 and 2, open circuit.

Hoping someone can help me figure out this problem. Thanks!

 

[Pieman44]

Hi everyone, hopefully as a collective group, I will be able to get some area to fault find. We have a 2011 2.0tdi 125 Passat. It was running fine with no issues, sat for about 6 weeks & no it will not crank at all. I’ve carbon load tested various batteries that I’m using which check fine, changed the starter motor( the code & all previous suggestions pointed to a possible issue), have a 12v signal to the starter, have cleaned the negative connection to the motor (transmission) & this thing still won’t start, both keys seem fine , car unlocks , all electrical components turn on when I try to start . At a loss where to look from here, we can’t move the car & am desperate need of some direction, I’m heading back to it now to rip the new starter out , hang it , then try the starter again, positive it will run but need to rule it out. TIA guy

 

[SilverGhost]

Sounds like something in Park Neutral safety switch, or Alarm/Immobilizer is prevent a start. More leaning to relay related to P/N interloc.

Obviously a 2011 Passat is more complicated than simple switch and relay with its smart key system, but that's the general idea.

I would switch ignition to on (15 power), then jump 12v to starter SOLENOID terminal 50 - that's the signal wire, not the battery wire. See if it cranks the engine, maybe lucky and starts. I think ECM won't let it start when you try to bypass the computer.

Jason

 

[Pieman44]

Sounds like something in Park Neutral safety switch, or Alarm/Immobilizer is prevent a start. More leaning to relay related to P/N interloc.

Obviously a 2011 Passat is more complicated than simple switch and relay with its smart key system, but that's the general idea.

I would switch ignition to on (15 power), then jump 12v to starter SOLENOID terminal 50 - that's the signal wire, not the battery wire. See if it cranks the engine, maybe lucky and starts. I think ECM won't let it start when you try to bypass the computer.

Jason

Thanks SilverGhost, I can see when I hook the meter up there is substantial drain on the battery (no matter what battery) I’m positive the starter is trying to do its thing. I’ve got to the point where I’m trying to move the crankshaft with a 19mm socket & it won’t budge. I simply am finding the t hard to fathom a engine which was perfectly fine & well kept with spontaneous crap itself because it wasn’t started for 6 weeks, this fault is blowing my mind, currently removing the glow plugs to see if there is any pressure build up that may be stopping it but I’m probably clucking at straws

 

[SilverGhost]

Maybe some time during those 6 weeks water leaking in or some "critter" moved in and something non-compressible is now jamming engine, preventing it from turning. Oh, and don't forget to make sure transmission is not jammed either.

Jason

 

[Pieman44]

Maybe some time during those 6 weeks water leaking in or some "critter" moved in and something non-compressible is now jamming engine, preventing it from turning. Oh, and don't forget to make sure transmission is not jammed either.

Jason

Hey SilverGhoust, have since ripped the glow plugs out to see if that relieved the pressure it did, found water in the head, eventually got the car started & had exhaust gasses in the coolant, thought the head had spontaneously gone but more probable is the egr cooler, will replace the cooler & see how much damage has been done

 

[SilverGhost]

Hey, at least this happened when starting instead of running at full speed. Less chance of bent conrods or such.

Jason

 

[B100]

In this case, the engine not turning over was a feature, not a bug. If there's a leak, maybe it's slow enough that no real effect when driving (anyone else ever use water mist to remove carbon?), or even sitting for a couple days. But six weeks let enough moisture seep into a combustion chamber to lock it up.

 

[karoliskark]

I have vw passat 1.9l tdi.

I borrowed my car for a few days and when i came back it couldnt start. It was cranking but no start. Eventually i got it started (by pumping gas pedal a few times) and it went into a limp mode(turbo was engaging rpm was jumping from 2k to 3k, but no acceleration). After that it seems to work fine.

Person that borrowed it said, if they press on the gas too much, it would shut off at the full stop and it would struggle to start again. When started it would work fine untill it happens again.

Cheap code reader didn't return any codes.

If i go to mechanic i would like to know what to tell them, so i can save as much as possible on unrelated changes and diagnostics. Or if its possible to fix it my self, i would rather attempt that.

Any idea what could be causing this? I would assume something to do with the fuel, because of the difficult starts, but I am far from expert.

 

[highender]

I wanted to add.... if your cars have these symptoms:

1- Car wont start...........but cranks.
2- Battery and starter were good and verified.
3- CAR cranks , but wont catch. AND >>> GLow plug "on ' light is not showing when starting. This is key.

4- - Fuel not gelled. No airleaks. Fuel pump ok. Glow plugs ok and harness and relay ok. All other fuses and systems ok.

Then it is most likely the RELAY 109 .

IT is located under the steering column and dash . Must pop off the lower panel by removing either Torx 15 or 20 screws ( four or five total. Then pop down and off.

Relay 109 is above a large black rectangular block of plastic ( about 4- 5 inches x 1.5 inch). Stick your head up and you can see the 1 inch x 1 inch x 1 inch cube shaped Relay 109. Simply pop it off...and replace with same.

Start the vehicle... glow plug coil light should now come on......and car should start .

Reinstall the lower panel by sliding panel between the white slabs in rear of firewall, and reinstall screws . ( this part can be tricky to re align )