964 misfire

[rich 36]

When I bought the car a couple of months back, driving it home I noticed an occasional' hesitancy'
most noticeable when revs fell below 2K (say on slowing in traffic)


[i]in other words gently applying throttle doesn't rev engine,
floor it, and it launches forward[/i]

Its become more apparent just this last fortnight, and particularly when warmed up.


looking back over its last service at La rose Porsche in Kent,on looking for misfire
they mentioned some corroded contacts on injectors/cylinders 4&5,
which they temporarily repaired, but suggested replacement of might need doing at some point.

Seeing as how 4&5 happen to be the most accessible I unclipped them and took a look,
I mean they LOOKED OK to me, but I sprayed them with contact cleaner and replaced them but its not really made much difference.

JZ said its not an uncommon job, and One they could do easilly and parts aren't at all dear




Anybody else changed these, or had similar symptoms?

[nine6four]

When I first had mine I had similar problems normally after filling her up. Turned out to be a dodgy carbon fuel canister. Wasn't an expensive job and you can tell if it is this as when you open the fuel cap there would be a sudden release of pressure.

Good luck,
James

[rich 36]

Tell me more, I'm going to station in the morning as its almost empty now.

is their a noticeable noise when the cap comes off the tank?

[Jappo]

Happened to my Dad's 964 twice. First time it was the belt for the dual distributor - it was only driving one of them, the second time turned out to be a dodgy tankfull of BP Ultimate.

[rich 36]

That bloody belt again,

I've been hoping not to have heard that TBH

Had a look at checking it the other week following some very helpful advice from owners on here,

but gave up for fear of shearing off the completely un-seeable screw on the back of the dizzy.

Booked it in for inspection at recommended garage locally Saturday week, so see if they have known similar probs

[melv]

rich 36 said:

Booked it in for inspection at recommended garage locally Saturday week, so see if they have known similar probs

Hope that local garage is a Porsche specialist!!!

Best of luck!

[rich 36]

Well, top-end cars at any rate.

they came recommended off here actually, I'd much sooner have a go at these little niggle myself
but at the risk of killing the car and waving bye bye on the back of a truck
I'll bite the bullet and drive it there


(while I still can)

[warmfuzzies]

Disconnecting coils will tell you if one has gone south, or the dizzy belt has gone. Should start on either primary or secondary.

kevin.

[wildoliver]

Yep disconnect low tension side of coil 1 with engine running, engine speed should dip slightly, then refit and do the same with coil 2, should also dip slightly.

If engine totally dies with one disconnected then belt has gone.

[rich 36]

Now,
following my question, I read through Pelicans relevant forum and found
'Hesitation'

Unsurprisingly I'm not alone experiencing this.


O2 Sensor appears to have failed, new One sought probably off E-bay Tonight

I've heard them mentioned before, but no-ones yet explained their purpose

My Earlier SC had some air pump clamped on the back to increase fresh air into the exhaust
for the American market....
but it MUST be more use than that

[wildoliver]

Euro car parts are about the cheapest for lambda's at i think about £14 from memory.

Could be maf too.

Did you try the coil test?

[rich 36]

I've not no.


Not completely sure what I'm loooking for TBH,
the last time I looked at a coil, it was round with a king lead and Two wires on wither side, a quick look under the cover told me to ask for a bit more detail before poking about.

I looked about pelican as now I'm 'Mac' I can't actually search in the usual way, as my browser simply closes down,
so during a search in the old way, I happened across the exact same symptoms I'm experiencing


corrected for big clumsy thumb typing on a BB

Edited by rich 36 on Saturday 15th September 22:38

[warmfuzzies]

O2 sensor realy acts as a feedback loop with respect to fuelling, and it will normally make the car run rich when off, make sure you get the real deal some of the OEM sensors have little in the way of water proofing and have been known to play up when wet. A genuine part is about £102 from an OPC.

Kevin

[rich 36]

Not really even seen copy parts on offer yet

if it has to be an OPC so be it
are they fiddly to swap?

[warmfuzzies]

Not fiddly, though they are likely to be rusted/stuck in. When I replace mine as I knew it was going to be difficult, I hamered the top off to put a socket on, as spanners often round the flats of. Then it's simply pull it through the bulkhead and conect it up behind the blower fan.

Take your wheel off and the blower fan, then simple really.


Kevin

[wildoliver]

Get an open end and ring spanner, disconnect the plug first use the open ender end over the wire on to the flats and it will pull it out ok. If it does round it don't stress just hacksaw the stub off and get an impact socket on it, it won't come to that though if your careful.

Seriously buy the cheap aftermarket (walker i think it is) one from ECP, it is so much cheaper, is waterproofed, has the same quality wire, is a straight swap pull out old one fit new one. No point in spending £90 more for something that does the job no better.

Oh and I am on mac too, get firefox for mac makes life far better than safari!

The coils are indeed what you describe, left hand side of engine bay, tucked up behind the fusebox, follow the Centre leeds back, they have little rubber boots, just pop off one of the low tension wires off coil one, then replace, then do the same on coil 2. the engine should not die, it is ok if it dips a little though.

Oliver

[rich 36]

Will you try the search option over there and make sure it functions....

the last time I dared draw attention the UK suddenly became a giant aircraft carrier for uncle sam

[wildoliver]

yep works fine for me, rennlist too.

[rich 36]

Firefox you say

will do

[warmfuzzies]

rich 36 said:

Firefox you say

will do

Then download and use Adblock for those annoying ads.....brilliant plugin/extension.

Kevin