Cant start car :(
Discussion
Had my 924S for 6 months nearly and love it to bits, but in the last few days i cant start it! The starter motor is turning over but the engine wont even start to rev. Im getting a good oil pressure when i try to start it and the spark plugs are all fine. Strange thing is it can be bump started with no problem....can any1 help? Thanks for your time gents 
Correct me if I am wrong, but you are saying:
1. It won't start if you try and start it on the starter motor, although it will turn over.
2. It will start fine if you bump start it.
I'd say your battery may not be kicking out enough puff to turn it over and fire the plugs. Diagnostic - try starting it with some jump leads connected, from another car. If this works (i.e. it does start) then your battery is on it's last legs.
If not, we'll think again.
Oli.
1. It won't start if you try and start it on the starter motor, although it will turn over.
2. It will start fine if you bump start it.
I'd say your battery may not be kicking out enough puff to turn it over and fire the plugs. Diagnostic - try starting it with some jump leads connected, from another car. If this works (i.e. it does start) then your battery is on it's last legs.
If not, we'll think again.
Oli.
Here's my thoughts:
1) Battery: Could be suspect, especially if (for example) it has not being getting a good charge from the altenator. Six months old or six years old, poor charging will kill it. Also, the voltage you measure before cranking doesn't mean much. What does it drop to when you try to start? (Best measured with a DVM rather than relying on the gauge in the car). Jump start from another car is a good idea as this would rule out the battery easily.
2i) Starter Motor: Power connections. How good is the wiring from the battery to the starter (big fat cable) and also what condition is the engine earth-strap in? If either are suspect, then the battery can't deliver full power to the starter, and thus the crank speed is too low.
2ii) Starter Motor: Does it crank constantly when you turn the key, or does it drop out just as the car is about to fire? If you bump-start the car, and run it until fully warmed up, can you then start it off the key? Or does it always fail?
3) Fuel Pump: Obviously the fuel pump is running when the engine runs, but is it running when the engine cranks on the starter? If it isn't getting power in the "start" position, then you can crank until the world ends/ hell freezes over / England win a world cup, but she won't fire!
If I think of anything else, I'll pop back.
Sheepy
1) Battery: Could be suspect, especially if (for example) it has not being getting a good charge from the altenator. Six months old or six years old, poor charging will kill it. Also, the voltage you measure before cranking doesn't mean much. What does it drop to when you try to start? (Best measured with a DVM rather than relying on the gauge in the car). Jump start from another car is a good idea as this would rule out the battery easily.
2i) Starter Motor: Power connections. How good is the wiring from the battery to the starter (big fat cable) and also what condition is the engine earth-strap in? If either are suspect, then the battery can't deliver full power to the starter, and thus the crank speed is too low.
2ii) Starter Motor: Does it crank constantly when you turn the key, or does it drop out just as the car is about to fire? If you bump-start the car, and run it until fully warmed up, can you then start it off the key? Or does it always fail?
3) Fuel Pump: Obviously the fuel pump is running when the engine runs, but is it running when the engine cranks on the starter? If it isn't getting power in the "start" position, then you can crank until the world ends/ hell freezes over / England win a world cup, but she won't fire!
If I think of anything else, I'll pop back.
Sheepy
Take a plug out and get hold it agaist the block while someone turns over the car on the starter. Is it giving a healthy spark? If not then there is obviously an issue on the ignition side. If there is a spark, then previous comments on the fuel supply may be the answer.
Hey you experts out there - is this not potentially a DME relay problem (does a 924 have a DME relay?)? Seem to recall that this sort of symptom was pretty typical of the DME relay being knacked, though am not sure that a bump start would do the trick if that was the case.
Hey you experts out there - is this not potentially a DME relay problem (does a 924 have a DME relay?)? Seem to recall that this sort of symptom was pretty typical of the DME relay being knacked, though am not sure that a bump start would do the trick if that was the case.
Ok there is no spark when i take the plug out, rest it against the block and start it. If the car is bump started its possible to turn her off and start her with the keys. I tried this after an few hours and it would still start, but after leaving it overnight it wouldnt. Does that reduce the number of possibilites?
Seen this before, could be one of 2 things.
No 1,Ignition switch fault. e.g. switch worn at start position so it doesn't dsend power to the coil when you turn the switch to operate the starter.
No 2,Coil or low tension supply.
When the battery is powering your ignition circuit on a push start the car fires up, however when you operate the starter at the same time the battery isn't putting enough voltage through the coil, therefore no spark and no start.
Good Luck, finding the fault's a complete b'stard, but you'll get a massive hit when you fix it.
No 1,Ignition switch fault. e.g. switch worn at start position so it doesn't dsend power to the coil when you turn the switch to operate the starter.
No 2,Coil or low tension supply.
When the battery is powering your ignition circuit on a push start the car fires up, however when you operate the starter at the same time the battery isn't putting enough voltage through the coil, therefore no spark and no start.
Good Luck, finding the fault's a complete b'stard, but you'll get a massive hit when you fix it.
As hinted at before this is one of 2 issues.
Depends how fast it turns over on the battery, if it turns over properly on the battery ie fast then its ignition switch.
If its slow and sluggish then its not providing enough power for the ignition and starter motor, hence why it will bump off, and hence why it will start after a period of time, this is the most likely suspect, and it iwll be due to a duff battery, duff alternator or poor earth, this one sounds like battery or earth, test for earth by a seperate earth lead (jump lead) connected between negative on battery and a good earth on engine, the lifting eye is usually good.
If it still doesn't start bang a new battery on.
Depends how fast it turns over on the battery, if it turns over properly on the battery ie fast then its ignition switch.
If its slow and sluggish then its not providing enough power for the ignition and starter motor, hence why it will bump off, and hence why it will start after a period of time, this is the most likely suspect, and it iwll be due to a duff battery, duff alternator or poor earth, this one sounds like battery or earth, test for earth by a seperate earth lead (jump lead) connected between negative on battery and a good earth on engine, the lifting eye is usually good.
If it still doesn't start bang a new battery on.
Ive replaced the DME relay with no positive effect, and have worked out why its possible to leave it for 1-2 hours and still start it: because the engine is warm. As a student with little amounts of my loan left, I really dont want to send it to a garage unless I have to. Thanks angain for your time and knowledge guys!
Have you tried jumpstarting the car when it is cold (and won't fire). This will eliminate the battery as a cause.
Have you checked things like the engine earth-strap(s)?
You say that there is no spark when you ground a plug to the block and crank. I've only ever found this to wrok reliably when the plug is new, and an area to be grounded against is cleaned for good connection. It is quite easy to not get a spark! he most reliable method would be to use a timing light and see if it flashes when you crank (ie the sensor picks up a signal from the HT-lead). If you don't get a spark on an HT-lead from the dizzy, what about on the HT-Lead from the coil to the dizzy (obviously unplug the dizzy end). Would eliminate the dizzy cap + rotor arm.
When it does start off the key, does the engine seem to turn any faster than when it doesn't start?
I begining to agree with those who suspect the battery. I think it isn't holding charge too well. After a run, the car starts because of the charging that took place during the run. After sitting for a time, the battery starts to lose charge and thus the cranking isn't fast enough to kick the beast into life.
Sheepy
Have you checked things like the engine earth-strap(s)?
You say that there is no spark when you ground a plug to the block and crank. I've only ever found this to wrok reliably when the plug is new, and an area to be grounded against is cleaned for good connection. It is quite easy to not get a spark! he most reliable method would be to use a timing light and see if it flashes when you crank (ie the sensor picks up a signal from the HT-lead). If you don't get a spark on an HT-lead from the dizzy, what about on the HT-Lead from the coil to the dizzy (obviously unplug the dizzy end). Would eliminate the dizzy cap + rotor arm.
When it does start off the key, does the engine seem to turn any faster than when it doesn't start?
I begining to agree with those who suspect the battery. I think it isn't holding charge too well. After a run, the car starts because of the charging that took place during the run. After sitting for a time, the battery starts to lose charge and thus the cranking isn't fast enough to kick the beast into life.
Sheepy
Okay chaps....here's the full monty........
Jump started from another car (or tried to)....no difference.
Earthed the battery (which is good) to another point on the engine....no difference
Dropped down to the local Porsche specialist who said that the speed of the starter motor (which is only 6 months old) sounds very good.
So...all in all, I think we can discount both the battery/ground issues and the starter motor itself.
The DME relay's been replaced, and the fact that the car starts on a bump - even when cold, tell's me that the coil's fine too. Once started, the engine runs like a peach.
Therefore, it can only be either the ignition switch or some engine sensor somewhere.
But either way, it doesn't account for the fact that once the car's hot, she'll start on the key! It just doesn't make any sense.
Help me please - it's driving me mad!!!!!
Jump started from another car (or tried to)....no difference.
Earthed the battery (which is good) to another point on the engine....no difference
Dropped down to the local Porsche specialist who said that the speed of the starter motor (which is only 6 months old) sounds very good.
So...all in all, I think we can discount both the battery/ground issues and the starter motor itself.
The DME relay's been replaced, and the fact that the car starts on a bump - even when cold, tell's me that the coil's fine too. Once started, the engine runs like a peach.
Therefore, it can only be either the ignition switch or some engine sensor somewhere.
But either way, it doesn't account for the fact that once the car's hot, she'll start on the key! It just doesn't make any sense.
Help me please - it's driving me mad!!!!!
If the lights go out when the starter is engaged, then if the wiring is fine and the starter is good, it'll be because the battery is flat. You have to find out why.
It'll either be because of the alternator, or because of static drain. Since it's allright after a run, I'd say that the alternator is good, but it's not guaranteed.
That probably just leaves static drain.
This is easy to find. Connect an ammeter in series with the main power circuit. To do this disconnect the main positive terminal of the battery, set the meter to amps, and connect the meter between the free red wire, and the battery + terminal. Whilst you have the meter set like this, don't try to turn the starter or you will blow the fuse in your meter.
Look at the current. It shouldn't be more than 5mA absolute max. If it's bigger, then remove the fuses one by one until you find the circuit that reduces the current to almost zero.
It'll either be because of the alternator, or because of static drain. Since it's allright after a run, I'd say that the alternator is good, but it's not guaranteed.
That probably just leaves static drain.
This is easy to find. Connect an ammeter in series with the main power circuit. To do this disconnect the main positive terminal of the battery, set the meter to amps, and connect the meter between the free red wire, and the battery + terminal. Whilst you have the meter set like this, don't try to turn the starter or you will blow the fuse in your meter.
Look at the current. It shouldn't be more than 5mA absolute max. If it's bigger, then remove the fuses one by one until you find the circuit that reduces the current to almost zero.
dilbert said:
If the lights go out when the starter is engaged, then if the wiring is fine and the starter is good, it'll be because the battery is flat.
Unlikely ... he tried to start it from a jump start. Have to say, I'm confused. Can't explain that. Is there some switch somewhere which is not switching ... ? Sounds daft. Sorry.
Oli.
zcacogp said:
dilbert said:
If the lights go out when the starter is engaged, then if the wiring is fine and the starter is good, it'll be because the battery is flat.
Unlikely ... he tried to start it from a jump start. Have to say, I'm confused. Can't explain that. Is there some switch somewhere which is not switching ... ? Sounds daft. Sorry.
Oli.
Hmmmm......
I'd forgotten that. What about the solenoid? Does it have one?
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