Another VR6 won't start thread

Discussion in 'VR5, VR6 & Wx' started by pjones, May 16, 2013.

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  1. pjones New Member

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    All,

    I've spent most of the day reading this forum and have learned a lot, but not enough it seems. I'm hoping someone can help with my fault finding. I don't have anything as exciting as a GTi but just a 2000 Caravelle (T4) with a VR6 engine. I know this is a GTi forum but you guys seem to know so much about the VR6 engine. I have limited diagnostic tools, a multi-meter and generic Bluetooth OBD-II, and mostly have no one to help crank the engine etc. Below is most of the information that might be relevant:

    - 2000 Caravelle (T4) VR6 automatic gearbox
    - left standing for around 1 year with no battery, was running before that
    - bought a new battery and the engine cranks fine (have been keeping the battery topped up with a decent C-Tek charger)
    - except for a brief period of around 3 seconds, the engine hasn't attempted to fire at all
    - have removed 1 plug and verified that it is sparking (haven't done the other 5 yet)
    - HT leads were new just before it was 'parked up'
    - when I turn the ignition on, there is no check engine light on the dash, but other lights come on (I've read this means ECU is not running)
    - if I crank the engine for a long time the low oil pressure warning light comes on
    - I have no relay in position 3
    - I have a 167 relay in position 12
    - all fuses are good
    - every minute or so there is a whirring for around 5 seconds, can't identify where due to ambient noise but I'm guessing the fuel pump?
    - I'm in Phuket and there's no VW dealer, I don't want to call in one of the local, let's guess and try rip & replace 'mechanics'
    - I connected up the OBDII and it said it's communicating with the ECU but claimed no logged/pending/historical codes

    <BLOCK VID= DATE= 2013.05.16 - 18.11.35 >
    <AIR_STATUS_SECONDARY= 00000100 00011010 />
    <AUXINSTATUS= />
    <BAROMETER= />
    <DIESELRAIL= />
    <DISTANCE_MIL_ON= />
    <DIST_SINCE_DTC_CLEAR= />
    <DTC= />
    <EGR_COMMANDED= />
    <EGR_ERROR= />
    <ELM_VERSION= ELM327 v1.5 />
    <ENGINE_CALCULATED_LOAD= 1.5687 />
    <ENGINE_RUNTIME= />
    <EVAP_COMMANDED_PURGE= />
    <EVAP_VAPOR_PRESSURE= />
    <FUELSTAT= 00000001 00000000 00001000 />
    <FUEL_ETHANOL_PCT= />
    <FUEL_LEVEL= />
    <FUEL_PRESSURE= />
    <IMAP= />
    <LOAD_ABSOLUTE= />
    <MAF_FLOW_RATE= 2.7700 />
    <MILDTCINFO= 10000000 00000111 01100101 00000100 11110101 />
    <MONITOR_STATUS= />
    <O2SENSORS= 00000011 00011010 />
    <O2SENSORS2= />
    <PRESSURE_FUEL_RAIL= />
    <RPM= 0.0000 />
    <SPEED= 0 />
    <TEMP_AIR_AMBIENT= />
    <TEMP_COOLANT= 29 />
    <TEMP_INTAKE= 30 />
    <THROTTLE_POSITION_RELATIVE= />
    <TIME_RUN_MIL_ON= />
    <TIME_SINCE_MIL_CLEAR= />
    <TIMING_ADVANCE= 0.0000 />
    <TPS= 3.5295 />
    <TRIM_LONG_BANK1= 0.0000 />
    <TRIM_LONG_BANK2= />
    <TRIM_SHORT_BANK1= 0.0000 />
    <TRIM_SHORT_BANK2= />
    <VIN= />
    <VOLTAGE_CONTROLMODULE= />
    <VOLTS= 12.5 />
    <WARMUPS_SINCE_DTC_CLEAR= />
    </BLOCK>

    I left the logger running whilst cranking the engine and it basically removed everyone of those values to being blank, except for volts, which dropped to 12.3.

    So I've now decided to stop 'poking around' and ask the experts for help rather than risk doing any damage. At this time I don't know whether my ECU is powered/working or not. I don't know what I should be checking next. All suggestions of next steps are gratefully received.
     
  2. mat-mk3

    mat-mk3 Administrator Admin

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    It sounds like the crank sensor. Does your rev counter move at all when cranking the engine?
     
  3. vw_singh Events Team Paid Member

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    Crank sensor always throws a fault code on an unstarted or non-starting vr6.

    Mine was a failed fuel pump. Easy test is get some easy start spray and spray it in through the air mass meter while cranking. If it starts then you know it's fuel related.

    Gurds
     
  4. pjones New Member

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    Thanks for the suggestions guys. What I've learned today:

    - rev counter reads ~220 rpm whilst cranking the engine
    - easy start sprays are not available in Thailand, perhaps as it doesn't get cold. I don't know what to use instead but the throttle body is horizontal so I can't just poor fuel in.
    - WD40 can't be used as it now uses CO2 as the propellant

    Access is very hard without lots of disassembly on this van. To verify fuel supply I suppose I could disconnect the output of the fuel pressure regulator and crank the engine for a few seconds?

    I'm still wondering about the ECU too. It seems the MIL light needs to show with engine stopped/ignition on, and in my case there is no MIL at all. From another thread:

    [​IMG][/url][/IMG]

    and from the Bentley manual:

    [​IMG][/url][/IMG]

    It seems I need to be sure that the ECU is working. I don't have the VAG test plug to check out the MIL light but I doubt that the bulb has failed. I'm not sure of all the functions performed by the ECU. If the ECU was not working would I still get a spark? Many posts point to the 109 relay in slot 3, but I have no relay there at all. I've read that is normal in some cases. How can I troubleshoot and be sure my ECU is working?

    It seems to me that I now need to know whether or not my ECU is working and if fuel is being delivered.

    Thanks in advance for any further suggestions

    Paul
     
  5. mat-mk3

    mat-mk3 Administrator Admin

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    If you can scan the ECU for codes when it's working. However the values should not turn blank when cranking unless that's just your scanner tool. Do you have a function to read the RPM with it and then crank the engine to tell if the ECU stays powered up while turning the engine over.
    The wuring sound for a couple of seconds should be your fuel pump priming and this works with the ECU. However if the ECU relay has gone and turns off while cranking then it obviously would not start.
     
  6. pjones New Member

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    That's exactly what's throwing me off. Many things point to the ECU, but when I plug in the scan tool it says it is connected. It is just a generic ELM327 Bluetooth device. The list I gave above is everything that it reports. The SW is basic though and just an Android version, I'll see if I can find my more advanced PC software and try to pull more information.

    Today I tried a little more diagnosis. The first whirring that occurs at ignition on is the throttle body, that goes for around 10 seconds and then stops, so no concerns there. The other whirring that happens every minute or so, I've not yet found.

    In order to verify fuel supply, I pulled the feed to the fuel pressure regulator and cranked the engine. No fuel at all, zero! I pulled relay 167 from position 12 and tested it works, off vehicle. Haven't yet tested the socket to see if it's being energised. I suppose it may also be worth hooking 12V directly to the fuel pump to check that it is functional? So at least I now know there's no fuel being delivered. Now I need to try and find out why.

    Thanks,

    Paul
     
  7. Trev16v

    Trev16v Paid Member Paid Member

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    (Above post approved.)
     
  8. pjones New Member

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    I've managed to do a little more testing, though not sure I'm making progress.

    - The scan tool shows RPM whilst cranking, around 195rpm
    - There is no power to the 4-pin plug on the fuel pump, I measured red/yellow wire to ground and got 0V. Also the brown wire measures 0 Ohms to ground.
    - The fuel pump relay is switching on when I turn the ignition key.
    - I've measured the fuel pump relay socket and pin 30 has +12V
    - The back of my fuse board has nothing in Z1. Shouldn't this be the output of the relay that turns the pump on. There's no loose wire that I can find.

    So I'm a little bit lost with where to go next in my troubleshooting.

    Paul
     
  9. mat-mk3

    mat-mk3 Administrator Admin

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    Z1 is injector power, I also have nothing in mine and had a VR6 and my 24V running.
    Not sure why it should be a wiring fault if you have touched nothing and it was running when you put it away. Could be the fuel pump has gone?
     
  10. pjones New Member

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    Thanks Mat. I've read conflicting posts, some saying must have Z1 and couple saying they don't. Glad to hear you don't have Z1 connected. I agree, shouldn't be a wiring fault as nothing has changed since before. Shouldn't I see +12V on the fuel pump connector though? Can I just 'hot wire' the fuel pump (with connector removed) just to see if it works?
     
  11. rubjonny

    rubjonny Administrator Staff Member Admin

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    yes you shoudl see 12v to the fuel pump when the relay is triggered, the fuel pump pin is on the M plug, see the fusebox FAQ :)

    Z/1 is sometimes used for injector power, and sometimes the ecu relay is used instead it depends on the age of the VR6. first of all, try swappign relay #18 into the fuel pump relay socket, this will bring the fuel pump live with the ignition. if it does, your relay is toast. if not, its the fuse or wiring at fault. if you have an alarm or immobiliser this may be the problem, so check that out too
     
  12. pjones New Member

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    thanks for the advice.

    - put relay no.18 into the fuel pump socket and measured between M1-M2 and got power.
    - measured at fuel pump plug and got power.
    - plugged in and fuel pump works :thumbup:
    - once again I bench tested relay no. 167 and it works fine on the bench [:s]
    - anyway, decided from frustration to buy a replacement. Drove all over Phuket and couldn't find one. Found a mechanic with a Jetta parked outside his place so dropped in. He pulled no.167 from the Jetta and plugged mine in, Jetta started up and runs fine, so seems my relay is fine after all.
    - got home, tested again, no.18 brings the pump on, no.167 doesn't.
    - I got the meter out and confirmed pin 2 and pin 6 of the relay socket both have +12V.
    - Wiring from pin 4 should be ok as with relay no.18 plugged in the fuel pump runs.
    - How do I check from pin 3?
    - G1/03 has +12V

    I don't have any add on alarm, should only be the immobiliser that came as standard. I'm using the original key. I don't know how this system works but is it possible that after being left without power for 1 year that this caused a problem? How can I check and eliminate the immobiliser.

    Thanks again for all your inputs. We must be getting close now!

    Paul
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    g1/03 should be earthed by the ecu, this is what triggers the pump relay. by the sounds of it you have a short in the loom, which is going to be fun to find I think! to test this, unplug G1 and earth pin 3 with the ignition on and the 167 relay fitted (tricky I know!) the fuel pump should run. if it does, bad news the engine loom or ecu need looking at. if not, its the fusebox!

    the car should start and run with relay 18 fitted if its only the ecu trigger wire to g1/3 at fault, but this is not safe in the long run as if you had a crash the pump wont cut out.
     
  14. pjones New Member

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    Thanks, very useful information. I was wondering if relay pin 3 needed to be pulled to ground to trigger as when I did a continuity check it was o/c to ground.

    - Manually shorted G1/03 to ground and the pump comes on
    - fuel comes out of the top of the pump (pulled the hose to check)
    - pressure regulator is still dry, even after leaving the pump running for many minutes. Is there a shut off valve somewhere?

    Something I didn't mention, as it's not supposed to be relevant, is that I had LPG (sequential) fitted many years ago. It always ran fine, and was running fine when I parked up. I rang the installer today to double check and they insist that they do not install a pump shut off relay and that they leave the pump circulating. They also insist that pulling the fuse from the LPG ECU leaves the car in 'stock' configuration. I pulled the fuse before doing all this testing. I've searched around and can't find an extra relay anywhere but I can't help but be concerned that maybe, for some reason, the guy who installed 5 years actually did put another relay in.

    Not really sure what to do next.
     
  15. rubjonny

    rubjonny Administrator Staff Member Admin

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    id assume the lpg system has its own pump, so the control of that would be down to whoever put it in there! I dont know anything about them so I cant advise there. all I know is the stock vw fuel pump relay is controlled by the ecu via earth to g1/3, so if you crash and ignition cuts the ecu kills the fuel pump relay. if the LPG system somehow taps into this wire for whatever reason then maybe this is the culprit, if there is an LPG ecu somewhere in the bay trace all the wiring from it looking for wire taps into the factory VW harness :)

    the VR6 golf at least doesnt have a shutoff valve, it is plumbed directly to the fuel pressure regulator. again maybe the lpg system will have something to do with this, i assume it will have some kind of control over the fuel delivery system? or maybe there is a fuel shutoff valve specific to the caravelle vr6 but I doubt it.

    what it could boil down to is a fault in the lpg system or wires from it to the factory vw system, so that even if you pull the fuse to disable it there is a fault which stops the factory fuel system operating as it should. This is my feeling, but its not something I can offer much more help with!
     
  16. pjones New Member

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    I've managed to download the installation instructions for the LPG ECU and according to what I think I understand the only place that it's 'supposed' to cut into the factory loom is it takes the negative off each petrol injector to trigger the LPG injector instead. I know some installers do add a fuel pump (petrol) cut off but it's not required by the system I have and the installer insists they haven't. Anyway, I can't help but think this could be the source of the problem and it has been into several different mechanics since the install, so who knows what may have been done? (unless we're at a main dealer here we normally get a handwritten sheet of paper with a lump sum number and very little detail).

    My challenge now is that the Caravelle engine bay is very inaccessible and has a sump guard that's hard to remove without ramps. My plan now is to get into the LPG ECU and set it up so that I can start it up using LPG (starts on petrol until warm by default). If I can do that then at least I can drive to a garage and then do some more searching with it up on a ramp.

    I hope to find the answer soon as I'll be visiting the UK in a couple of weeks and that's my best opportunity for buying parts.

    Thanks again for all your advice.
     

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