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Joined: 07 Apr 2014
Posts: 132
Location: Hertfordshire

PostPosted: Mon Apr 10, 2017 7:41 am    Post subject: Reply with quote

Another little update. So over the weekend I had a little bit of time and took the Boxster for a bit of a test. I drove it for a good 15 mins or so on the hottest day of the year - it got up to temperature gradually and then held there in the correct spot. This was encouraging.

When I parked up with it still running, I checked in the boot and there was no steam escaping and no nasty sounds or smells, in fact I could hear the coolant circulating at the top of the coolant tank which says to me there was no excess pressure. Heaters are nice and hot so no air locks there and I kept the bleed valve open to try and squeeze any last bits of air out.

I'm cautiously optimistic as I feel if there were exhaust gases escaping into the coolant, I would have known about it by now. I need to give it a slightly longer test now.

On the negative side however, the starting issue occurred again when I had stopped it for about 30 mins. First start was absolutely fine however upon starting up again it took a good amount of effort for it to start. Once started however it ran like a dream.

Its very annoying as I still cant rely on the car at the minute and being so intermittent, its not easy working it out. I think now I really need to get someone with the full Porsche software to plug in and see what the various sensors are doing. Still has a 'crank sensor' feel to it. The fact that it has now been hard to start when warm as well, rules out it being a temperature sensor issue. I obviously have a spare known working crank sensor but I cant get the original one out. Its really stuck in there.

The only other thing I can think of is one of those annoying things that often gets over looked and that's a dodgy old battery. Might stick my 996 one in and see if it makes a difference.
02 996 C4S
93 Skyline R33 GTS-t
91 CRX vtec turbo
01 986 Boxster S
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Fast & Furious
Fast & Furious

Joined: 04 Oct 2010
Posts: 7557
Location: East Midlands

2001 Porsche 996 Targa

PostPosted: Mon Apr 10, 2017 3:06 pm    Post subject: Reply with quote

You can test the crank sensor with a multi meter to see if you are getting voltage supplied (I think you should be getting 5 Volts??) and the ohms reading (can't remember the figures) when hot and cold, this will give a you a clue as to whether the sensor is at fault before you have to butcher it off.

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Joined: 07 Apr 2014
Posts: 132
Location: Hertfordshire

PostPosted: Thu Apr 13, 2017 3:57 pm    Post subject: Reply with quote

Resistance should be between 0.8 and 1.0 KOhms at around 20 degrees C so cold engine. Its worth me checking that to see. I've ordered some service parts for it anyway as I feel a little more confident know the coolant issue looks like it may be solved. It will have a new air filter and fuel filter to go along with the new plugs. Am hoping to do a bit more diagnosing on the dodgy start issue at the weekend.
02 996 C4S
93 Skyline R33 GTS-t
91 CRX vtec turbo
01 986 Boxster S
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Joined: 21 Mar 2015
Posts: 4455
Location: Brighton

PostPosted: Thu Apr 13, 2017 7:30 pm    Post subject: Reply with quote

Crank sensors dont always throw up a fault code for intermitant non start faults but hot and left or just getting hot is when they tend to fail .

Its a weak signal basically and a good scope is the best way of checking but its dificult to get it in the non start position when checking it .

Resistance check is certainly worth doing but may not prove its actually faulty .

Changeing when its seized in .. well .. gearbox out is the best option , its the same sensor as abs and drilling is pretty much out , the magnet snaps drill bits .. ive spent 3 hours drilling one out on a 928 before and i had access to that .. its a mare of a job .

Assumeing no fault codes on a non start then fuel pump / pressure is the next thing as the car doesn,t know this so cant generate a code for it .

7pm - 9pm
At an Indy these days !
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Joined: 07 Apr 2014
Posts: 132
Location: Hertfordshire

PostPosted: Wed Apr 19, 2017 9:19 am    Post subject: Reply with quote

Time for a small update - not that I have done a great deal. I did however take it for another 20 minute drive and no overheating and no sign of steam escaping which is positive. This is obviously my main concern as the starting issue will be relatively simple and will get sorted. If the cooling issue isn't fixed then obviously its an engine out job which I really don't have time for. There was a little coolant dripping down afterwards however which was clearly coming from the drain tube at the back. Checking in the boot however, it definitely wasn't coming from the filler cap (brand new 04 cap fitted as a precaution already) yet the top of the bleed valve was a little damp. I changed the seals on this recently and upon double checking the screws were fairly loose so I guess they have loosened as the seals settled so I tightened them up and hopefully that's all it was.

My brothers E46 M3 has spat its dummy out and needs a new HG (as a minimum) so annoyingly this has moved ahead in the list of things to do however I plan to keep working at the starting issue.

Again the issue is still there but at the moment it does still start every time eventually. When I first went to start it, it started right up on the button. Next few times throughout the day - it took some encouragement. When it nearly starts but doesn't quite manage it, I get quite a loud squeal which I'm fairly sure is coming from the starter. I know this is fairly common and at 90k miles its probably relatively worn. I didn't consider this could be the issue and to be honest I still don't really but regardless I'd like to sort this out as its a nice simple job and I can clean and check all the cables at the same time. I'll pop the motor out and take it to my local auto electricians for a rebuild. I guess it deserves it at 90k miles.

I also replaced the cabin filter which looks like it was probably the original - absolutely filthy. Also did the fuel filter which again looked really old.

I'm waiting on a new air filter and drive belt to arrive as well. I'm basically changing all the serviceable's so I know exactly where I stand with the car. I must say when its running - it feels like new - really impressed.

Eventually this is going to be a great car - I do feel like I'm slowly getting there with every hour I find to work on it.

I think I'm confident enough now with the cooling system to drive it to a specialist to check the crank sensor.
02 996 C4S
93 Skyline R33 GTS-t
91 CRX vtec turbo
01 986 Boxster S
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