missfire on 996, only happens when raining
missfire on 996, only happens when raining
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DucatiGary

Original Poster:

7,765 posts

252 months

Thursday 28th July 2005
quotequote all
hello

just wondering if anyone else had this strange problem?

it has rained alot latley, and i forgot to put the porsche in the garage twice now, dont get me wrong, ive never had a problem before this and this is not a serious problem.

basically i warm the car up before leaving, when i get to the end of the road the engine missfires oncce, and the warning light comes on, it is fine after this and the engine has NO problems but the warning light stays on, so I go to porsche, pay em to say, "there nowt wrong with the car sir" and today it happend again.

I have put a cover over the spoiler tonight (cant get it in garage at the moment, going to make room tomorrow, and will see if it happens again.

the mechanic asked if i had done anything recently that is not normal and leaving it in the rain over night was the only thing, he said it was probbably somthing to so with that.

no problems when its been dry after the first time, but today it rained heavily and it did the same, once, and the light is on. (heavy rain today, car left out in the rain again.

once the engine is about 60 degrees the car is 110% fine, I think the water evaporates and the problem is gone ?

anyone got any ideas? i dont wanna go to porsche again pay em a wad of money to test it for an housr and say "the car is running better than most we have had in here for a while, there is nothing wrong with it, that will be X amount of money, thanks"

pls help

marx

61 posts

262 months

Thursday 28th July 2005
quotequote all
Might be damp. Wife's Fiesta has the same problem. Once the car's warmed up, it'll be OK. Used to spray WD40 on the electrics, but don't know about this on modern cars. Has your 996 got individual HT coils per spark plug?

verysideways

10,268 posts

299 months

Friday 29th July 2005
quotequote all
Had almost exactly the same problem on one of my 993's - turned out to be the king lead (the one that goes from the coil to the distributor).

Took it off and it was "dusty". Looked like oxidized aluminium (if you know what that looks like).

Rather than clean it up i just got a new lead - perfect from then on.

DucatiGary

Original Poster:

7,765 posts

252 months

Friday 29th July 2005
quotequote all
yes it has dual coils, i will replace the lead VS mentioned, thanks very much for the help guys! booking it in now , have a good weekend.

DucatiGary

Original Poster:

7,765 posts

252 months

Friday 29th July 2005
quotequote all
6 coils being replaced :P, booked in

Henry-F

4,791 posts

272 months

Friday 29th July 2005
quotequote all
The 996 (and Boxster for that matter), have individual coil packs on each spark plug rather than a seperate (or two seperate in the case of dual plug engines), coil(s).

Quite common for them to crack and a good owner will change them when this happens. By doing this you reduce the chance of moisture creeping in and upsetting things.

Henry

DucatiGary

Original Poster:

7,765 posts

252 months

Friday 29th July 2005
quotequote all
yes it looks like the plastic has expanded and has cracked on one, water must be getting in, others look like they are on the way out, all being replaced.

no rain today, no problems when i drove it to the specialist.

they couldent make the fault happen whith the computer hooked up, so coil packs letting in water it must be! (hope)

pgm

2,168 posts

276 months

Saturday 30th July 2005
quotequote all
had exactly the same on my 996

all six coil packs had gone - it was a warranty fix which i believe was a staggering £550!

DucatiGary

Original Poster:

7,765 posts

252 months

Saturday 30th July 2005
quotequote all
the specialist says it is a bi annual occurance to all 996 and boxters.

anyone know if you can get different coil packs ? once that are not plastic housed?

they said there was somthing else I needed to keep an eye on, vari valve or somthing? they say this should be replaced every 50k miles, mines done 50k.

anyone else heard of this? they recon it will cost £550 inc for the replacement as they have to get the engine out to get at them (one on each side, I think its something to do with the cam speed adjustment though i might be wrong) parts cost about £120 each.

not confirmed that I will have this done yet as the bill will be near a grand but they said after checking it over twice these are the only 2 suspect areas of the car and they recon ill have at least 12 months hassle free driving if I replace the parts they outlined.

Yes im new to 911 ownership, only had it 4 weeks now.

thanks

DucatiGary

Original Poster:

7,765 posts

252 months

Wednesday 10th August 2005
quotequote all
right, just to finish this thread.

car is back after 5 days in www.911sport.co.uk/ (my local specialist that was reccomended)

replaced 6 coil packs, 2 vari solenoids (one each side) piston rings, and 2 other sets of rings (not sure what they are but are on the bill) replaced plugs, gaskets, removed engine for complete inspection, changed oil filter and oil (last done 6 months ago by a specialist) there was 6 exhaust studs that they had difficulty removing (they state 27 hours labour but only charged for 8) and this is the main reason why the car was in for 5 days.

They checked for RMS too and said it is not as common in manual 996's as it is in tiptronic's, mines a manual and they say it was checked and its fine.

I gave them a open cheque book when i gave it to them, asked if they could go over it and replace anything that is either on its way out (within next 12 months) or needs replacing.

the garage owner (phil) says I am lucky and the car is in very very good condition.

total bill, warranted for 12 months, £1026.46 inc vodka and tonic

i dont work for them and as ive only just bought the car 6 weeks ago I would like to give 911 sport the thumbs up for anyone who is local and needs their 911 fixing.

they had ferraris and a Bentley in when i took mine, and this assured me that they must know what they are doing, obviously there was several 911's.

they could of taken me for as much as they wanted but they never! cool

Phil Dicky

7,194 posts

290 months

Wednesday 10th August 2005
quotequote all
Nice 996 Gary, small consolation i know when you've just spent 1K on it.

Phil

Denis O

2,141 posts

270 months

Wednesday 10th August 2005
quotequote all
A "bag of sand" + to sort out a slight missfire when it's been raining and you say they never took you for what they wanted
I'd have bought a gold plated umbrella
Obviously a lot more work than expected and without the work you could have had some serious problems.

DucatiGary

Original Poster:

7,765 posts

252 months

Wednesday 10th August 2005
quotequote all
even though I bought the car with tons of history, and no expense has been spared, i dident expect to pay another grand to get it 100%

i do realise though that the car had only done 1800 miles in the last year and has been garaged from birth.

so me leaving it out of the garage might of done me some favours in the long term.

Im not the happiest after paying another grand for what was thought to be a pristine 996 celebration (modded of course) but im confident now its sorted that i will have 12 months hassle free ownership.

cheers