Lumpy start on warm

[FieldAtlanta]

The initial message was deleted from this topic on 21 October 2023 at 08:52

[deebs]

FieldAtlanta said:

Hi all, I’ve got a Cayman 2.7 Gen 1 987 which I purchased around 1 month ago. 2007 car with 38k on it and I’ve driven about 500 trouble-free miles since buying. Until now…

I did a good 20 min of driving yesterday evening so the temp gauge was bang in the middle and everything nice and warm. Stopped for 5 mins (turning off the engine) and when I went to turn the ignition back on the car kind of turned over, ‘caught’ and spluttered a bit but didn’t actually start. Tried again and it turned over for a bit longer than a normal start but did start. Did another few rounds of on/off and seemed to be okay but still took an uncomfortable and unusual amount of time.

I’m wondering if anyone has any suggestions on how to approach this? I have 6 month RAC warranty from the dealer. They’re a Porsche specialist (race team owners etc) and did a full check of the car before sale with nothing to report… Problem is they’re about 150miles from me and I’m due to drive the car to France tomorrow eve.

Only things that have changed with the car since noticing the issue is that I recently filled up with super unleaded (97RON) rather than the standard unleaded I had been using up to then. Would this cause anything weird? Perhaps I just didn’t notice before as I’d rarely stopped the car and started again while warm?

Appreciate any suggestions on what to do.

I've the same car on 64k miles, owned 5 years. I've had a couple of instances in that time of what you described when doing a 'hot start' . Not sure how usual or unusual it is for the car but it's happened that few times I've never had it checked out.

Point of the post: I think it'll be ok, give the specialist a shout and see if they've come across it before from the description but carry on using it.

[FieldAtlanta]

deebs said:

I've the same car on 64k miles, owned 5 years. I've had a couple of instances in that time of what you described when doing a 'hot start' . Not sure how usual or unusual it is for the car but it's happened that few times I've never had it checked out.

Point of the post: I think it'll be ok, give the specialist a shout and see if they've come across it before from the description but carry on using it.

Very strange! Have you ever had any battery replacements in that time? I haven’t got a trickle charger sorted yet (car is on driveway outside) but wonder if this may help?

[Magnum 475]

Mine (987S 3.2) does this from time to time.

Based on experience with similar configuration engines that use fully mechanical injection with manual mixture control (Lycoming flat fours and flat sixes), my first thought is fuel vaporisation in the lines to the injectors - the car is essentially injecting vapour instead of liquid fuel.

Mine usually pulls this trick at petrol stations - it's just long enough for heat to soak into the fuel lines before I try to re-start it.

[deebs]

FieldAtlanta said:

deebs said:

I've the same car on 64k miles, owned 5 years. I've had a couple of instances in that time of what you described when doing a 'hot start' . Not sure how usual or unusual it is for the car but it's happened that few times I've never had it checked out.

Point of the post: I think it'll be ok, give the specialist a shout and see if they've come across it before from the description but carry on using it.

Very strange! Have you ever had any battery replacements in that time? I haven’t got a trickle charger sorted yet (car is on driveway outside) but wonder if this may help?

I've always managed to keep mine on a trickle charge. I have changed the battery this year, although I've barely driven it and it's such an infrequent occurrence I couldn't link the two at this point.

Like magnums experience above mine has predominantly done this at fuel stations from a hot start from memory.