deykamp

Recently, my car will "hit" during a cold start, but most of the time it will not stay running and will start on the next attempt. After I have stated it and ran it for awhile this is no longer an issue....ONLY when it is cold.

No erratic idling, no missing, no performance loss, no stalling.

Rotors, Plugs, Distributor caps, O2 sensor replaced (< 1 year)
Valves adjusted.
ISV valve cleaned...was not dirty
MAF was cleaned awhile back (Not part of the equation?)

Car will run on either coil/distributor.
No apparent vacuum leaks (lots of hoses).
It is running rich the initial 2-3 minutes after starting.

Idle switch does "click".
What do I check to make sure the switch is working and/or would this cause this problem?







Thanks.
Dale
'91 C2 CAB

Rocket Rob

I would check your cylinder head temp sensor and confirm that it has the right resistance for a warm and cold engine.

sml

i had the same thing.

i think it was fixed with a bosch hammer idle adaptation.

darth

How old are the spark plug wires in years/miles?

chris951

Failing DME relay or you need a hammer adaptation

deykamp

I have a new DME relay, but put the original back in the the circuit and no difference.
Why would I need a hammer idle adaptation all of a sudden after running it for nine years?

The plug wires may be the originals; I saw no receipts indicating they were changed. 95K miles, 22 years old.

I would check your cylinder head temp sensor and confirm that it has the right resistance for a warm and cold engine. Where is this located and what are the readings, pins etc.?

sml

has the battery even been disconnected in nine years?

has your batter lasted nine years? maybe time for a new battery.

Rocket Rob

The cylinder head temp sensor is on the left hand side of the engine at the front side. What are the proper readings?

Degrees C Resistance (ohms)
0 4.4k - 6.8k
15-30 1.4k - 3.6k
40 1.0k - 1.3k
80 250 - 390
100 160 - 210

If you have access to a Scantool or Hammer, you can see this value on the tool. If a temp sensor is faulty, the engine will have starting problems (no cold start enrichment).

deykamp

The battery is new and on a trickle charger.
I do not have access to a Scantool or a Bosch Hammer.

Can you get to the sensor from the top and/or does it have a plug in connector for the I/O?
What pin numbers or can you get the readings off the DME ?

Thanks for all the input....

Rocket Rob

The sensor can be read either at the sensor's connector in the engine compartment or at the DME connector. The pins at the DME are terminal 45 and terminal 30.

sml

so you haven't done the system adaptation then? that could be the problem.

find a mechanic or ask here for someone nearby who may own one.

Richard Curtis

at worst, an idle adaptation is 15 minutes of labor plus the scan tool. Any Porsche mechanic should be able to accommodate you, especially if there's one you use reguarly. Mine did it for free; car subsequently ran incredibly better.

Rocket Rob

Where are you located? Maybe there is someone with a Scantool near you.

deykamp

Lawton, OK
I suppose the nearest Porsche mechanic would be Oklahoma City, OK

Dale
'91 C2 CAB