[CANUCK GTS]

Engine misfires due to bad coils.

I picked up my new 718 Cayman GTS with PDK in April, 2018 and followed the break-in procedure for 3000 km. After the break-in period I noticed a hesitation of power under hard acceleration around 5000 rpm. It happened about two weeks later, other than that it's been running great. A month ago there were apparent misfires, however no engine codes came up. I called the dealer and he said to ensure that I'm using 94 octane. It's not easy to find around here so I've been using 91 octane. There's one gas station in town with 94 octane so filled up with that and it made no difference. Still the odd misfires with no engine codes. Took it into the dealer and they did some test runs and confirmed the hesitation so recalibrated the PDK.. didn't help. Finally after about 3 test runs an engine code came up = Misfires in cylinder 3 and 4. They changed out the coil for 4 and had to order in a coil and spark plug for 3. Runs great now and seems to have even more power than ever. I asked the service manager what could have caused it but he said it was probably just faulty coils. All under warranty but Porsche has some history now on possible coil problems.

They also added the grills on the side intakes.

 

[GregW]

I'm glad it's finally working for you. It should be a blast on BC roads--I have family in Vancouver and on the Island.

I doubt if Porsche makes its own coils, and like all electronic stuff it can test fine and then break down early or run almost forever. That's what the warranty is for.

Running the proper octane petrol will let the engine management unit adjust for maximum performance. Sub-standard petrol will affect the overall engine performance rather than cause specific problems--unless it is really below "acceptable".

(I can't understand the difficulties in getting real 'hi-test' in North America. Way down here in Australia the proper octane fuel is available everywhere I go, and even higher grades are in most petrol stations.)

There are some octane enhancers available but the tests show that some work well and others give only a one number increase. The tests are out there on the 'net--I saw them once but they were irrelevant to me so I didn't take note. DuckDuckGo is your friend.

 

[ZuffenHouseRules]

Engine misfires due to bad coils.

Thanks for sharing this. My takeaways wrt dealer service departments response to performance issue in absence of engine code:
1) blame octane
2) blame PDK (or any other readily 'reset' software)
3) once code captured, the problem is quickly and fully resolved under warranty

It used to be the problem had to be re-created (at service center) before it could be solved; now it has to throw a code.

 

[CANUCK GTS]

Thanks @ZuffenHouseRules and @GregW for your replies. The service manager said there wasn't much they could do until it shows an engine code even though they've got the most sophisticated diagnostic tools out there.

 

[misterllaneous]

I have a 2018 CGTS 6MT and I feel the same hesitation in 5th gear between 4k and 5k. Haven't taken it in to the dealer yet, but good to know the unfortunate experience is being felt by others.
You mention test runs. Did the dealer take it out or how did they run the diagnostic?

 

[CANUCK GTS]

I took it out with the service manager to show him the problem. Then two techs took it for a drive with the OBD scanner attached.. One drove while the other tech viewed the diagnostics readout.
Your description of a hesitation is more like what I felt than an actual misfire.. so likely a bad coil or spark plug.

 

[misterllaneous]

Thank you for getting back.

 

[7JamesJohnMarshall]

Good afternoon

I am from the UK and have a 2018 718 Cayman GTS. I have also noticed what I believe to be a similar problem to yours - ONLY under hard acceleration the car almost gets stuck (there is a big jolt) and then continues. Always towards the top of the rev range and 1 in 5 times if in automatic mode, between 3rd and 4th gear the car won't automatically shift up a gear (I have got into the habit now of using paddles if accelerating hard).

Are these similar symptoms to yours?

I haven't reported it to my dealer yet, It is good to hear that I am not the only one experiencing this. I have only ever put 98RON fuel in the car (Shell V Power).

Thanks
James

 

[misterllaneous]

It doesn't sound like the same problem. I have not gotten to the end of the break-in period so I have not experimented with revs higher than 5000RPM.
My hesitation comes in between 4000-4300 in 4th or 5th gear under gradual acceleration and it is very faint.
I took out a Porsche tech with 17 years experience and he was noticed it as well. He also believes it is coil or spark plug related and because its under load and not constant it is not cam timing related.
I have another appointment next week and will update after.

 

[CANUCK GTS]

I was experiencing a hard jolt in the high revs above 5000 rpm in gears 4-6. It was pretty sudden and harsh. The service manager initially tried re-mapping the PDK transmission but that wasn't the problem. New coil and plug in cylinder 3 and new plug in 4 fixed the problem.

 

[misterllaneous]

Interesting, I haven't reached that range yet, will be interesting to see once I get there.

 

[misterllaneous]

Update.
Picked up the car today. Dealer replaced coil and fouled spark plug from Cyl 3. I have not had a chance to test it out, hopefully this weekend and hopefully the issue is resolved.
During diagnosis, the car did not throw a code, but looking at the live data on the Porsche diagnostic computer with the tech in the car, Cyl 3 was showing a negative value under acceleration at the RPM range that I had identified.

 

[7JamesJohnMarshall]

Update.
Picked up the car today. Dealer replaced coil and fouled spark plug from Cyl 3. I have not had a chance to test it out, hopefully this weekend and hopefully the issue is resolved.
During diagnosis, the car did not throw a code, but looking at the live data on the Porsche diagnostic computer with the tech in the car, Cyl 3 was showing a negative value under acceleration at the RPM range that I had identified.

Did that solve your issue? @misterllaneous

 

[misterllaneous]

Did that solve your issue? @misterllaneous

So far so good, however I have only added a few hundred miles so far since the repair and I can't say I've felt the misfire since. I'll give it a couple more runs before I come to a final conclusion.