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And still the ace engine won't start!!!!!!!!!

Discussion in 'Classic Audi Forum' started by robonmac, May 26, 2008.

  1. robonmac
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    robonmac Member

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    [May 26, 2008]
    Iv'e searched the other threads and whilst similar do not quite answer my problem.
    Travelling down the road the other day the 2.0 16v coupe died without notice.Towed it home and tried to source the fault but to no avail.The RAC couldn't find the fault and suggested plugs and a dizzy cap....PAH! Wot £60 for no reason,don't think so!
    Anyway i checked at the metering head and there was a leak in the main braided fuel line to the head,changed that and it made no difference,the car cranks but doesn't start,well i say that but once or twice it did turn over but ran for only 10 seconds.Still wont start,checked the dizzy cap and it was fine,as well as the rotor.Besides the distributor has been reconditioned from probe about a year ago so i dont think that is it.i placed a steel rod at the plug end of all the leads and got a spark arcing to an earthing point,i also suspected the injectors so i cleaned them and checked all the fuel lines to those places.I even replaced the whole metering head with a used one but there is plenty of pressure coming in from the previously changed fuel line so i dont think that is it,as a last resort i even did change the plugs but again made no difference,the plugs appear to be wet when cranking so i think that this is ok only that the first plug(nearest the bulkhead)is blacker than the others??
    I am still presuming that it may be the hall sender or do these 16v's have an ignition module-could that be at fault?? but without vagcom i am stuck!
    Does anybody know the procedure to check these parts in laymans terms?
    Cheers
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  3. scotty33
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    scotty33 Member

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    [May 27, 2008]
    Hi

    My Haynes does not cover the 16v, but the 3A 8v is Bosch motronic, and it suggests fault codes can be read using the blink code method, this may work on your 16v?

    http://20v.org/tools.htm#VAG1115
    Tools and Parts


    http://20v.org/fault.htm
    Diagnostic Fault Codes

    It's worth mentioning that the l.e.d. has to be connected the right way around, and they are generally 2v which means a resistor is needed to make it work on the 12v system. If you were to use a 1.2 watt lamp, this is the same spec as the 'check engine light' fitted to Californian cars, there would be no resistor or polarity problems?

    I think the diagnostic connector plugs are in the fusebox on B4 models?

    The Haynes also says the hall sender test is only needed if there is no spark

    Good Luck
    #2
  4. audi5e
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    audi5e Member

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    [May 29, 2008]
    interesting that you managed to get the car running for those 10 seconds. I wonder if there isn't a dropoff in fuel pressure as the car runs?
    #3
  5. robonmac
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    robonmac Member

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    [May 30, 2008]
    I wondered that but how can i ever tell?
    I unbolted the fuel pump line coming out of the fuel filter(located underneath,next to the fuel filter, i think?) and got my ever able girlfriend( that makes me sound young!!!god i'm 36) to crank the car and loads of fuel came spurting my way,so it seems that is in order,however it has no longer managed to start,on some occasions it is so close but not quite there.
    Right lets have a check:-
    Fuel pressure ok.
    Fuel relay.ok
    fuel pump.ok
    Fuel in tank. ok
    Injectors clean.ok
    Metering head .ok
    New ignition module.ok.
    Spark from HTlead to distributor cap ok.
    New leads.ok
    New spark plugs.ok
    Spark at all leads while attached to spark plug to engine block.ok
    Spark plugs wet with fuel after cranking.ok
    Distributor was refurbished by probe a year ago?
    New Cap and rotor arm by beru replaced by a year ago (Still in good nick)

    I'm getting bored.Can any one tell me if those obdII leads off ebay are any good to install vag.com?
    I cannot afford to buy the system from Ross tech nor pay for someone to check it out.plus i do not like to be beaten.
    If i get a sparking arc from a disconnected ht lead from the coil to the distributor ,does that mean everything before the dizzy is fine? or is there a case for a weak arc? how can i tell.if i presume that an arc to the distributor cap means that there is enough power then you have to suspect the dizzy or cap itself,The cap is newish and the contacts look ok,as does the rotor arm,the dizzy was refurbished a year ago and there is a spark at the end of the leads/plugs.This is not to say that a dizzy cannot go wrong but if i get some kind of spark is that ok?
    or can there be a WEAK spark that is not enough to crank the car.
    The coil is is a suspect but if i get a spark does this mean it's ok?
    The RAC man( HAH!. 3 hours to tell me it needs new spark plugs.)suspected it may have a weak spark to numbers 2+4.but how can you tell? (under a shady tree at night?).
    The car is a coupe 1993 2.0 16v ACE and i dont know which cylinder is which. bulkhead being number one or front end of car being number one .Anyway what is the firing order and how can you tell if the R.A.C. man has re-connected the right leads at the dizzy or not?
    Help?
    #4
  6. robonmac
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    robonmac Member

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    [May 31, 2008]
    Replaced a cold start valve ,fuel pump relay,another coil,all cheaply from a scrapper i know but what the heck,and still nada!!
    Finally called out a mechanic who then spent 2 and a half hours scratching his head,he put his snap-on diagnostic on it and it instantly read Throttle position fault!
    After much more detective work he realised that there was no power getting to the device on the side of the fuel metering head(on top of the airbox,,a bosch unit)and also no power going to the plug to the throttle position sensor?
    Does anyone know how to trace the electrical supply to these parts,it is not the fuse so could it be a relay ?the fuel relay clicks nicely on ignition so could this be ok?
    I have a multimeter so can anyone tell me how to test these two power plugs myself.Please help. two weeks without a car!!
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  7. NineNails
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    [Jun 1, 2008]
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  8. scotty33
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    scotty33 Member

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    [Jun 1, 2008]
    Hi

    From what you write above, there could still be an ignition problem, I read that the 16v ECU prevents the fuel side of things operating unless the ignition system is healthy. I'm struggling with the idea that the timing may have slipped, but as the car was running and ground to a halt it suggests something failed, or a wire went open circuit/shorted?
    I'm guessing but would think that the electrical supplies you are missing are from he ecu, if you can figure out which wire is which you could check the output at the ECU itself, or check the wires' continuitity? But you may be wasting your time if there IS an ign fault?
    You probably already know? but the ACE engine is covered in the 100/A6 Haynes manual.
    Something like a broken earth wire would not show up on a scan and is hard to find if you are not looking for it.
    #7
  9. robonmac
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    robonmac Member

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    [Jun 2, 2008]
    Thanks for the help guys,still struggling with this one,had an old throttle sensor so changed that and guess what,still the same,i agree with you scotty in that with the car running and then instantly dying it would suggest a malfunction of a component rather than a timing issue,i'm no expert but what would be the chances of say a timing belt slipping a tooth or two or the distributor moving-its rock solid at the moment!
    Anyway if it was timing then surely the car would start but run erraticly.
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  10. scotty33
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    scotty33 Member

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    [Jun 3, 2008]
    Hi

    You might think so so, but on the 20v cars the distributor (hall sender to be precise) provides the ECU with an engine position reference which means the window for error is quite small. I think the situation is similar on the 16v?
    #9
  11. audi5e
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    audi5e Member

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    [Jun 7, 2008]
    I had an issue on my last Audi where the throttle position sensor was faulty (turned out to be full of dust/mud which was shorting everything out) causing the computer to think the car was on idle so it would not allow me to rev the engine... only ever happened when the car got hot, presumably the mud got more conductive with heat...

    Have you checked the compression of each cylinder, sorry, just trying some of the more obvious mechanical stuff...
    #10
  12. audia6tripping
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    audia6tripping New Member

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    [Apr 23, 2009]
    Had starting problem with my last 90 Quattro. Drove me nuts every time I out it in to get fixed worked OK eventually changed both the crank sensor and timing sensor turned out it was one of them - garage did not know which I was only glad it was fixed. My car did however start with short push, 10 feet, Does it start when pushed? Made it a total pain and didn't liek to take anywhere owing to th ereibility issues
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  13. audia6tripping
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    audia6tripping New Member

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    [Apr 23, 2009]
    Had starting problem with my last 90 Quattro. Drove me nuts every time I out it in to get fixed worked OK eventually changed both the crank sensor and timing sensor turned out it was one of them - garage did not know which I was only glad it was fixed. My car did however start with short push, 10 feet, Does it start when pushed? Made it a total pain and didn't liek to take anywhere owing to th ereibility issues
    #12

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