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I had an issue with mine like 2 year ago, I thought it was the starter going out, I had already had HPFP replacement.
I even bought the damn starter to be replaced.
I get to my local indie, we crank it like multiple i.e 3-5 times to start.
He walks of and comes back with a jump starter and hooks up to the car.
Car started every time multiple times.
Check the voltmeter on your car what it is reading. It has to be at least marginally above 12 otherwise no dice.
The issue came back again 4 months ago. I just changed the battery myself and carried on.
This is the most battery sensitive car I've ever driven.
This is the most battery sensitive car I've ever driven.
Which is why the correct group size should be used.
I know this-
When I hook up the PIWIS to do anything I usually plug it into the wall power adapter instead of letting it power through the obd port. The first thing I always do is check voltage @ the DME. Without a battery charger on @ least 40a hooked up I can only run diagnostics for about 10 minutes before voltage starts to drop to around 12 which isn't enough. You can't forget that even though the battery may show X amount of V, what
matters is the V that actually makes it to any of the 40+ control units. These vehicles are getting older and so does the wiring. I've gone thru all my main power cables and grounds, that isn't the problem. Re-wiring the whole vehicle isn't sensible so that leaves us at needing to use the proper rated battery no matter what physical size is. Currently that is a group size 49 or H9.
Sorry for reviving an old thread. I'm having the same issue as the original poster - did you ever manage to fix this issue?
Sometimes mine cranks for less than 1 second before cutting out, other times 2-3 seconds.
A few posts on here mention the fuel pumps. I do have a "lean" code on one bank, but I'm not sure why this would cause the car to stop cranking. Every other car I have owned would crank indefinitely with the fuel pump disconnected.
I emailed a specialist in the UK who responded with the following message:"We have had this before and it is down to the timing chain that is stretched, they have a very long chain with one tensioner. The reason it cuts the starter motor out is the engine control unit engine speed signal is increased quickly as one of the cam-shafts is allowed to spin quickly due to slack in the chain and then the engine control unit cuts the crank signal to the starter motor as it thinks engine has started."
please help clarify for those of us that still have no definitive answer
i will refer to ScootCherHeinie post of 1/5/2019 at 6:36pm.
the ongoing problem with multiple key turns before full cranking of engine and starting. the starter is cut off until multiple attempts when it then fully engages and starts the engine.
there are multiple answers most of which relate to a bad starter, bad fuel pump, and weak battery. also have seen the ones about corroded wires under the carpet and bad relays.
like many, i have followed and traced all of these without resolving the problem. fuel pump replaced, starter replaced, battery replaced, relays replaced, wires checked and all good.
finally took to porsche dealer who informed me that timing chain was stretched with a 21 degree cam deviation on bank one. it was explained to me that due to this the ECU senses this, due to the speed of the camshaft from the slack, and cuts off the crank signal to the starter. this seems plauseable based on the symptoms. BUT , does not explain why after multiple attempts the engine finally cranks and starts.
indeed after 235,000 miles and poor prior oil change maintenance, the timing chain is worn along with the guides and tensioners creating and "out of time" situation. BUT, in my experience with multiple other vehicles,
i have never had a vehicle not crank continuously even with a worn chain or broken timing belt. they would not start or run like crap but they always would crank.
for the benefit of other porsche owners that are not as familiar with these cars or their systems; PLEASE, SOMEONE CONFIRM THAT INDEED THE ECU WILL CUT OFF STARTER SIGNAL INTEMITTENTLY BEFORE CONTINUING TO CRANK AND START. this would surely help a lot of non expert porsche owners to stop chasing their tails and spending money unnecessarily.
i will refer to ScootCherHeinie post of 1/5/2019 at 6:36pm.
the ongoing problem with multiple key turns before full cranking of engine and starting. the starter is cut off until multiple attempts when it then fully engages and starts the engine.
there are multiple answers most of which relate to a bad starter, bad fuel pump, and weak battery. also have seen the ones about corroded wires under the carpet and bad relays.
like many, i have followed and traced all of these without resolving the problem. fuel pump replaced, starter replaced, battery replaced, relays replaced, wires checked and all good.
finally took to porsche dealer who informed me that timing chain was stretched with a 21 degree cam deviation on bank one. it was explained to me that due to this the ECU senses this, due to the speed of the camshaft from the slack, and cuts off the crank signal to the starter. this seems plauseable based on the symptoms. BUT , does not explain why after multiple attempts the engine finally cranks and starts.
indeed after 235,000 miles and poor prior oil change maintenance, the timing chain is worn along with the guides and tensioners creating and "out of time" situation. BUT, in my experience with multiple other vehicles,
i have never had a vehicle not crank continuously even with a worn chain or broken timing belt. they would not start or run like crap but they always would crank.
for the benefit of other porsche owners that are not as familiar with these cars or their systems; PLEASE, SOMEONE CONFIRM THAT INDEED THE ECU WILL CUT OFF STARTER SIGNAL INTEMITTENTLY BEFORE CONTINUING TO CRANK AND START. this would surely help a lot of non expert porsche owners to stop chasing their tails and spending money unnecessarily.
Yes, I had this issue 2 years ago. I was also sceptical, but this is indeed true. I had exactly the same symptoms: turn the key, it would crank for a second and then stop. Eventually it would start after a lot of effort.
The ECU cuts power to the starter motor if the timing is too far out. Mine got to the point that it could take up to 15 minutes of turning the key back and forward to start the engine. As a temporary fix, I would remove the starter motor relay and short out the pins with ignition turned on. This wasn't ideal, but it would force the engine to start every time after around 5 seconds of cranking.
My issue was also accompanied by a P0016 fault code. From memory, my timing deviation values were around 9 and 16.
I eventually fixed it properly by realigning the timing chain. I purchased a timing alignment kit on eBay (approx £50) and did the job myself. It wasn't too difficult in the end, the hardest part was removing one of the rear valve cover bolts which was up against the firewall, but this was easily remedied by purchasing a very small tilting 1/4" ratchet. Everything was done from above, and I didn't remove the fan. I used a suitably-sized drill-bit to lock the crank, as the pins included in the kit were too long to fit with the fan in place. A mirror or camera helps to see what's happening here, space is quite tight.
After the adjustment, the timing deviation values were approximately 1 and 3 which is well within tolerance. It was fine for another 12 months until I sold the car, and the deviation values never went back up. I would recommend taking this route before replacing the entire timing chain.
It's possible a bad chain tensioner could cause this. The reason it eventually starts is because while cranking the hydraulic portion of the tensioner is pumping back up and tightening the chain and it's the sping portion of the tensioner that's weak.
Yes, I had this issue 2 years ago. I was also sceptical, but this is indeed true. I had exactly the same symptoms: turn the key, it would crank for a second and then stop. Eventually it would start after a lot of effort.
The ECU cuts power to the starter motor if the timing is too far out. Mine got to the point that it could take up to 15 minutes of turning the key back and forward to start the engine. As a temporary fix, I would remove the starter motor relay and short out the pins with ignition turned on. This wasn't ideal, but it would force the engine to start every time after around 5 seconds of cranking.
My issue was also accompanied by a P0016 fault code. From memory, my timing deviation values were around 9 and 16.
I eventually fixed it properly by realigning the timing chain. I purchased a timing alignment kit on eBay (approx £50) and did the job myself. It wasn't too difficult in the end, the hardest part was removing one of the rear valve cover bolts which was up against the firewall, but this was easily remedied by purchasing a very small tilting 1/4" ratchet. Everything was done from above, and I didn't remove the fan. I used a suitably-sized drill-bit to lock the crank, as the pins included in the kit were too long to fit with the fan in place. A mirror or camera helps to see what's happening here, space is quite tight.
After the adjustment, the timing deviation values were approximately 1 and 3 which is well within tolerance. It was fine for another 12 months until I sold the car, and the deviation values never went back up. I would recommend taking this route before replacing the entire timing chain.
matthew, you were lucky that it is all you had to do. i was planning the same until it was confirmed that my issues were more severe. good thing you sold because it was only a matter of time before the root of the problem (worn guides and stretched chain) would require a much bigger job.
petza, you are absolutely correct. however, when it gets too bad !!!!! the only fix is timing chain guides. when you open it up you will find worn, broken and debris. please note, this would not happen IF owners would just properly maintain these vehicles with timely oil changes.
01-15-2019, 04:10 PM
