amet

Was wondering if anyone had the similar issue and if anyone can help diagnose the possible cause.

if i try to start the car it will sometimes 'die' immediately on start, subsequent attempt is always successful. only happens when the car is warm/hot and never in the mornings, I assume this is due to teh fact that idle speed is higher on cold engine

to make things worst, few days ago I came off highway and as I approached the traffic light car seemed to misfire and threw 2 warnings at me, auto start/stop was disabled and PSM disabled, safe to drive carefully.

What was odd was that engine seemed to run on 5 cylinders, I switched it off and on and it all ran fine after that. Of course that dealer had no idea what was causing it and PIWIS didn't throw any errors when I took it in.

I cant shake the feeling that 2 issues are somehow related, any ideas from the fellow rennlisters?

Video below show what the issue looks like on start, unfortunately I didn't get the video/pic of the misfire and warning that appeared

CSK 911 C4S

Something doesn't smell right.

When you took it in to the dealer they said the car's computer didn't document the issue?

I'm not believing that especially since the car went into limp mode until you recycled the ignition. This is what the car's computer supposed to do.

How much fuel did you have on board?

amet

I was told that nothing came up on PIWIS, if they lied to me... I lied to you

not sure about fuel, but I would guess between 1/2 and 3/4

spiderv6

^ that is what the computer is for. It logs all of these things. Something doesn't add up. Have access to another dealer?

CSK 911 C4S

Let's hope it was a freak occurrence.

amet

unfortunately not, there is only one dealer with 2 workshops.

amet

thanks guys for the answers, any idea why it would not start(or die when starting) as per the video?

CSK 911 C4S

I could not get the video to play. Check the link if you will.

When I hear of starting issues I usually think of cam position sensor problems but those should show up as a fault in the cars computer... if the sensor is on its way out that could even be the cause of the misfires that occurred.

It's a pretty inexpensive part and I think on the 991 it's easy to get to for replacement.

991carreradriver

It appears to be something akin to vapor lock - enough fuel to start the engine but nothing in the pipeline to keep it running. This is strange as I have never had anything like this even after maximum heat generated on the track. The Cobb Accessport is worth its weight in gold just because it can monitor what happened as its happening Let us know what you find out.

amet

spoke to service advisor, no luck getting anything done under warranty until they can reproduce or piwis throws an error at them.Might leave the car with them for a few days if they can organize a loaner.

I was wondering about fuel as well, but expected it to show same behavior in the morning start, so far mornings were fine and only issue is with warm car, around 2 hours after it has fully warmed up(if that makes any sense)

amet

and a quick update, car is now fixed by the dealer under warranty.

Engine Variable Timing Solenoid was the culprit, it took them few days to reproduce and find the issue as it was not throwing any warnings in piwis.

they also replaced rear tail light due to the moisture condensation, driver side window switch that was wobbly and disabled power steering plus.

it feels like a new car.... happy days...

HK G36C

Nice...under cpo or other warranty?

amet

CPO, I was debating if I should renew it ,car came with one year warranty in January 2016 and I renewed it in 2017... good call. I added up the work they have done and a prices they charge for parts in Dubai and this work alone paid for the warranty for one year.