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Minor Service and plugs done, but now an issue

FZP

Well-known member
Joined
18 Jan 2015
Messages
5,864
Problem:
As above, just had a minor service done along with s plug change. Since I've got the car back, when ever I start the car from cold, the engine stutters somewhat. After about a minute or so it disappears. Warm starts don't replicate the issue.
I've picked up a lovely cracked windscreen the day after I collected the car which is booked in for a replacement at the start of Nov due to logistics at my end.
Any ideas as to the above issue of the stutter. Am I going to have to get the car back to them before Nov?
 
I have an inkling ..

Assumeing it was fine before hand and is now slightly off .. not a misfire as such but a bit of lumpyness and mainly at idle .. then ....


Hmmm .. suspense ...

One of the spark plugs has a slightly bent electrode thereby making a shorted path for the spark ..

Downside is the only way to prove it is remove each plug in turn and check it.

I can say ive seen similar 1 month after an OPC did a plug change on a 996 Turbo .


other than that it must be an existing or a new fault .. but i dont like problems after a car has been worked on .. i always assume that has caused it untill i can prove otherwise .. which here i cant :(
 
Yes,
Lumpy is a better description. 100% not present before the service. I only changed the plugs due to being advised that it was time to, rather than performance related issues.
I'll have a chat with OPC tomorrow :thumb:
As always, many thanks for your advice it's greatly appreciated.
 
On a Gen 2 then doing it on time is important .. the plug threads protrude further into the cylinder on these and they carbon up .

They are always difficult to remove at 4 years .. i had one which was 2 years late .. i couldn,t get 4 of the plugs out .. i was afraid i was going to strip the threads.

A problem with a plug makes the most sense to me and ive seen similar before .

Just say .. since the plugs have been changed i seem to have a slight misfire can you either check them or tell me whats wrong .

If it is a plug then there probably wont be a fault code .

Its a pain i know .. but a lot of mechanics these days just fit plugs and not actually inspect them before hand .. ive had bent electrodes out of the box before .. or if its been dropped then a hair line crack in the ceramic .
 
If anyone doubts the depth of your knowledge, then send them to me and I'll sort them out.
I was summoned to OPC to discuss the issue you highlight above. 1 plug on each bank weren't keen on coming out and was advised of worst case scenario, snapping in situ. Thankfully after 3 days they managed to get the offenders out. The costs thrown around fix the above were eyewatering.
Bullet dodged. They did advise to get the engine up to speed and give it some to rid the carbon out of the cylinder. Any other advice on not having a repeat performance in 4 years time?
 
Bless you :D

The one i got stuck with .. i had managed to get the plugs out a bit but couldnt get them back in far enough .. got the customer back in a week later and the tiny amount of blow through on the plugs had freed them and i got them out ..

we are talking small here but plugs can blow past at times so not something i was concerned with .

My original suggestion was some sort of fuel cleaner in the tank and run it for a week .. didnt get done and no idea why but the above worked .. crack the plugs a bit then drive for a week ... this wasnt intentional .. i actually did the plugs up as tight as i could .. it was only on removal a week later that i realised what had happened .
 
deMort Rules! :bow:

There's not much better than free advice....excdept free advice that saves you money :thumb:
 
I've left the car with OPC, and like going to the doctors, can't replicate the issue. I told them to have a crack again on Monday.
 
Unless its painfully obvious that tends to be the standard respone im afraid .

To be fair though i used to be in the same position and if it wasnt obvious i needed to get onto the next car .. there is only so much time a mechanic can loose on a difficult fault before he gets hauled in the office ... every min of every day i had to be clocked on to something so they could anyalise and then basically tell me off for not having sold enough hours .

Sorry .. im rambleing ..

Im still with the possibility its a single spark plug which unless all removed and checked ( i doubt there would be a fault code here ) then they cant say either way and you will get a N.F.F * and the car back.

Hopefully they will have the car from cold and see there is actually a running issue with out a code then go from there .

I would say ask if a single plug could be faulty as the fault started from there but OPC dont really listen to people like me .. a forum guy !


* No Fault Found .
 
Thanks mate. Service manager and head tech couldn't replicate twice today. If they can't replicate on Monday morning, I'll suggest I'll head down on Tues morning to see if I can identify with them
 
Per deMort: "the plug threads protrude further into the cylinder on these and they carbon up". So Porsche designed an engine that doesn't fit their recommended spark plugs! Another example of great engineering from the company that was once seen as the epitome of German automotive engineering.
 

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