Drop in performance

[Guest]

HI

Im running a 964 C4 91 (very nice it is too - but thats a different story)

Had very bad running probs yesterday like fuel running out, but I had a 2/3 tank. Stopped 4 times through town and had my kids with me, raining and then the police turned up.

Managed to get to the local service guy, TWG and he replaced the DMG relay. That appears to have solved it but now its running off power.

No go when you put your foot down in 5th and need to drop to 3rd to get any action.

I just seems sluggish, he put it on a diagnostic box and said no probs reported then replace the relay.

Any suggestions for the performance drop off?

 

[Guest]

Should also ask if there are any 964 owners in the Peterborough or Cambs area that I could meet and have a run in thier car for comparison (you drive or course)

 

[Guest]

Johno

Did TWG disconnect battery after replacing DME ? , as I had a similar problem recently that only cleared after disconnecting the battery for 10 mins and then going for a 20 min drive.

Regards

Kevin S

 

[Elliot Davies]

Have you checked the distributor drive belt this would give a bit of an off feeling if it had snapped ?

More info at Johns http://www.porsche964.co.uk/ technical / Engine & Transmission / Broken Distributor Belts


As Kevin states, if the battery is disconnected, wait a while, reconnect and then go for a spirited drive to reset the DME.

 

[Guest]

Not sure about the belt inspection but I will try discon the battery

 

[Elliot Davies]

try that first and if it doesnt sort it out id certainly recommend checking the dissie drive belt as (not trying to worry you) it is said that it 'could' do damage to the engine as you are only using 6 spark plugs instead of 12 and one of the rotor arms will be fixed at the stopped position and sparking all the time at the same contact as the secondary dissie is obviously driven by the belt

A pic of a dissie drive belt.
More details at the link i gave you above

 

[Guest]

Ok did the battery this morning and it does seem a little better but only had a 10min drive to work so will try agin tomorrow morning.

Thanks

JohnO

 

[Guest]

Re did this at the weekend and seemed to help.

Still broke down on the way home, raining and late on the bypass out of nottingham stalled like no petrol. Exactly as before, raining and lights heater and radio on. Just overtaken a line of cars then had to pull in!!!!!

Then again at the next traffic lights - nice. Re started and drove the 50 miles home with no problems?

I think this may be an immobiliser fault rather then the relay itself, when the relay was changed it had stopped raining and dryed out.

 

[Elliot Davies]

Okay, i searched my old 964 saved mail archives and came up with this johno.

OXYGEN SENSOR ?

Driving yesterday evening, there was a jolt and a sudden loss of power.
Then the engine cut out at every junction and needed lots of revs to get it
to move without stalling. It missed at low speed but would drive at 40 mph+
OK but with poor acceleration. My immediate though was the dizzy belt. I
rang GT One this morning who told me how to diagnose the dizzy
belt by removing the plug into the distributors one at a time and trying to
start the car. This identified it as not being the problem, so I drove
steadily from Wiltshire to Chertsey so Craig could put the Hammer on it.
This revealed a problem with the Oxygen Sensor. Craig removed and re-fitted
the multipin plug from the back of it...problem solved. Its a common one
apparently. Someone with less integrity would have sold me a new sensor.
Anybody else have those heavy storms Sunday night ?

 

[Guest]

Thanks Elliot,

TWG put a hammer test on it and came up with nothing! So replaced the DME relay. This seemed to cure the problem at the time but as I explained it had then stopped raining and the fault appeared in similar weather conditions.

Im on a run down to cornwall this weekend so we will see if appears again.

Its been fine, both weather and car, all week so figures crossed!

Thanks again for the info, really appricate it even if I cant spell it.

JohnO