Faultless reliability record at an end! Help!
12-11-2006, 06:53 AM
#1
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Faultless reliability record at an end! Help!
Gutted. 964 has started first time, every time, until this morning (ironically 1 week after a 12k service).
Symptoms thus - immobiliser switches off in the usual way, no problem. Turn the key to the pre-ignition position and all the relevant dash lights come on, fan starts to whir etc. So far so good. However, when I turn the key to fire the engine, it doesn't start. Instead, the engine shudders repeatedly as though it is trying to fire but someone has jammed a stick into the engine fan, while the lights on the dash blink on and off in unison.
Got my brother to try and fire the engine while observing what happened in the engine bay. The fan is being turned incrementally by the belt on each attempted firing, accompanied by a loud and unpleasant judder from the assembly on in the top of the engine bay - where the throttle linkage sits (forgive the layman's terminology - not had to have the bonnet up much and not that familiar with the contents!)
I can't help but think that this has been brought about by the torrential rain we had last night, as the car ran fine all weekend. Based on my flaky description, does anyone have any ideas before I fork out for the AA?
Symptoms thus - immobiliser switches off in the usual way, no problem. Turn the key to the pre-ignition position and all the relevant dash lights come on, fan starts to whir etc. So far so good. However, when I turn the key to fire the engine, it doesn't start. Instead, the engine shudders repeatedly as though it is trying to fire but someone has jammed a stick into the engine fan, while the lights on the dash blink on and off in unison.
Got my brother to try and fire the engine while observing what happened in the engine bay. The fan is being turned incrementally by the belt on each attempted firing, accompanied by a loud and unpleasant judder from the assembly on in the top of the engine bay - where the throttle linkage sits (forgive the layman's terminology - not had to have the bonnet up much and not that familiar with the contents!)
I can't help but think that this has been brought about by the torrential rain we had last night, as the car ran fine all weekend. Based on my flaky description, does anyone have any ideas before I fork out for the AA?
12-11-2006, 07:26 AM
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Ah, thats is very hard to figure out going by that description.
1. You say immobiliser switches off in the normal way.
Are you sure about that? Obviously you are talking about an aftermarket immobiliser as the 964 doesn't have one factory, it's just an alarm only. So if
it's an aftermarket immobiliser than how many points of immobilisation are there wired up. If the fuel pump is immobilised and the relay has failed it will not let the engine fire up as it will be starving for fuel. Can you definitely hear the fuel pump working?
2. Make sure the DME Relay hasn't faulted (Very common)
3. Is the engine winding over at a decent speed e.g. Battety could be getting tired.
4. "accompanied by a loud and unpleasant judder from the assembly on in the top of the engine bay". That doesn't sound good at all? Explain this more please. You haven't just had a timing chain or similar done have you? Does everything look like it's in place in the engine bay. Does engine have plenty of oil in it (Check dipstick).
5. Check everything before trying to crank over engine again just incase.
Hope this helps. Good Luck
1. You say immobiliser switches off in the normal way.
Are you sure about that? Obviously you are talking about an aftermarket immobiliser as the 964 doesn't have one factory, it's just an alarm only. So if
it's an aftermarket immobiliser than how many points of immobilisation are there wired up. If the fuel pump is immobilised and the relay has failed it will not let the engine fire up as it will be starving for fuel. Can you definitely hear the fuel pump working?
2. Make sure the DME Relay hasn't faulted (Very common)
3. Is the engine winding over at a decent speed e.g. Battety could be getting tired.
4. "accompanied by a loud and unpleasant judder from the assembly on in the top of the engine bay". That doesn't sound good at all? Explain this more please. You haven't just had a timing chain or similar done have you? Does everything look like it's in place in the engine bay. Does engine have plenty of oil in it (Check dipstick).
5. Check everything before trying to crank over engine again just incase.
Hope this helps. Good Luck
12-11-2006, 07:59 AM
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Yes, apologies, it's nigh on impossible to adequately describe stuff like this without either an accompanying video or a fairly decent level of knowledge about what you're trying to describe. Cheers for the help though.
1. Yes, it's an aftermarket immobiliser. Have only be able to gauge whether or not it's switching off properly based on normal experience (i.e. the usual beeps and clicks). Am going to isolate it this evening to check it's not at fault, as that was my first thought too. Will check the fuel pump operation also.
2. From what I know about the DME relay, this doesn't sound like the issue. Will prob change it to be on the safe side though!
3 + 4. This is the odd part. The engine isn't winding over in the usual way - by this I mean, this isn't your classic 'car turning over and nearly firing but not catching despite vigourous throttle stamping and loud swearing' that I used to get on my old Jag XJ6. Rather, the engine turns slightly, stops abruptly, turns slightly and so on. Looking at the fan while this is happening, it rotates no more than 5 degrees each time. The "judder" is probably the result of the engine turn being continually interrupted. Fluid levels and battery are both fine.
Bizarre
1. Yes, it's an aftermarket immobiliser. Have only be able to gauge whether or not it's switching off properly based on normal experience (i.e. the usual beeps and clicks). Am going to isolate it this evening to check it's not at fault, as that was my first thought too. Will check the fuel pump operation also.
2. From what I know about the DME relay, this doesn't sound like the issue. Will prob change it to be on the safe side though!
3 + 4. This is the odd part. The engine isn't winding over in the usual way - by this I mean, this isn't your classic 'car turning over and nearly firing but not catching despite vigourous throttle stamping and loud swearing' that I used to get on my old Jag XJ6. Rather, the engine turns slightly, stops abruptly, turns slightly and so on. Looking at the fan while this is happening, it rotates no more than 5 degrees each time. The "judder" is probably the result of the engine turn being continually interrupted. Fluid levels and battery are both fine.
Bizarre
12-11-2006, 08:30 AM
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Are you definitely sure the battery is ok. Cos the way you just described the engine turning over from my end sounds like a faulty battery. It may be testing fine with a multimeter. What makes you think the battery is ok? Ok so the shuddeing doessn't seem like anything major than I am guessing from what you have just said.
This is a really hard one with out seeing the car so all you can do is:
1. Check battery is Definitely ok
2. Check immobiliser "(i.e. the usual beeps and clicks) , this doesn't mean it's ok
3. Check DME Relay
4. Check for spark etc etc
Again, ARE YOU SURE IT'S NOT A FAULTY BATTERY, it sounds like it to me mate?
This is a really hard one with out seeing the car so all you can do is:
1. Check battery is Definitely ok
2. Check immobiliser "(i.e. the usual beeps and clicks) , this doesn't mean it's ok
3. Check DME Relay
4. Check for spark etc etc
Again, ARE YOU SURE IT'S NOT A FAULTY BATTERY, it sounds like it to me mate?
12-11-2006, 09:54 AM
#6
Three Wheelin'
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You could try the old fashioned way and put the headlights on while cranking.
Do the lights dim to nothing while you are cranking ? Battery/ground problem
Do the lights not change ? Check the starter motor.
Not 100% infalible but at least gives you a clue using no test gear !!
Good luck
Geoff
Do the lights dim to nothing while you are cranking ? Battery/ground problem
Do the lights not change ? Check the starter motor.
Not 100% infalible but at least gives you a clue using no test gear !!
Good luck
Geoff
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12-11-2006, 12:30 PM
#8
Nordschleife Master
Battery !
Hows it do with a jump ?
"Do the lights dim to nothing while you are cranking ?"
------vs-------
"the lights on the dash blink on and off in unison."
Hows it do with a jump ?
"Do the lights dim to nothing while you are cranking ?"
------vs-------
"the lights on the dash blink on and off in unison."
12-11-2006, 12:45 PM
#9
Burning Brakes
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based on what you say i think something is wet in the ignition and spark plugs are misfiring. with the rain being the only change you mention i would pop the distributor caps off and have a looksee for moisture.
hope this helps
bill
90c2
hope this helps
bill
90c2