944 S2 Convertible 1990, Idles rough.

Rez 1 · 06-29-2003, 03:32 PM

Hi my 944 S2 1990 idles rough and sometimes but not always does not start due to no spark. I have replaced the spark plugs, the distrubitor/camshaft sensor and cleaned the flywheel sensor and it has made no difference, i replaced distrubitor/camshaft sensor part because when the cars is idling rough i disconected it and it made no difference to the running? i have checked the DME relay and the soldering joints looks okay and the car cuts out when removed. Also when the ignition is left on the fuel pump does not cut off? can anyone please advise.

Martin T · 06-29-2003, 05:05 PM

When it doesn't start try unplugging one fuel injector, if it then starts you need a new fuel pressure regulator.
When they fail the pressure goes high so this will also give a rough idle.
You may also have a faulty ign switch.

carsontc · 06-29-2003, 06:44 PM

Quote:

Originally posted by Rez 1
i have checked the DME relay....Also when the ignition is left on the fuel pump does not cut off advise.

weird

how did you 'check' the DME relay?

Mark_944S2 · 06-29-2003, 07:52 PM

What state are the rotor arm and distributor cap in? Also it could be the ignition leads especially if this is a cold start problem and its worse on colder days.

Rough idling (how rough?) was fixed on mine with the above.

Mark

Rez 1 · 06-30-2003, 03:44 AM

The promlem that i have is intermiternt and the fuel pump stays on, today I will replace the DME relay and see how it goes, I will also check the roter arm and cap for their condition.
As for the ignition switch where is it located? I will give this ago after i deal with the above. Thanks I will let you know how it goes.

carsontc · 06-30-2003, 06:18 AM

Quote:

Originally posted by Rez 1
i replaced distrubitor/camshaft sensor part because when the cars is idling rough i disconected it and it made no difference to the running?

even weirder

I thought the cam sensor on the S2 controlled the spark & fuel and without it connected the engine will not run

Pokrajac · 07-01-2003, 01:28 AM

Your problem is the Ignition Control Module.
I have owned a 944S for 10 years and mine
went out recently. Out of nowhere it would
idle really rough and die. This part is only on
the 944S/S2 series. It is located under
the hood on the right, behind your headlight
on the inside of the fender wall, can't miss it.
Look and see what the part looks like first by
going on a Porsche parts site and see what it looks
like. Bosh...............$65.48
Aftermarket....$45.87

I rock so you can roll................

Rez 1 · 07-01-2003, 02:13 AM

I have now replaced the DME relay the distrubitor cap, roter arm, plugs, and the engine still idles rough. I will enquire about a ignition control module.
Thanks.

Rez 1 · 07-02-2003, 05:44 AM

Today I replaced the ignition control module and the car is still the same Idling rough (the car starting problem has not returned for a while so all is okay there). Has anyone got any more suggestions on the car iding rough?
Thanks

cncone · 09:26 PM

Have you checked the plug wires & airflow sensor? Check Vacuum hoses for leaks.
http://www.clarks-garage.com/shop-manual/eng-15.htm
http://www.clarks-garage.com

Rez 1 · 07-03-2003, 06:04 AM

I have just ordered another Air Flow Meter and sould receive it soon. Plug wires seem okay, Hoses seem okay, Lets see how I get on with the other Air Flow Meter.
Thanks

carsontc · 07-03-2003, 09:58 AM

could test the AFM first at frwilk.com

have a read:

http://www.frwilk.com/944dme/afm.htm

Makis · 07-03-2003, 11:17 AM

Also check if O2 sensor is operating correctly.
Do a compression test, just to eliminate any mechanical problems that the engine might have and check spark plugs.

Rez 1 · 07-04-2003, 02:58 AM

That was good reading on the AFM, Thanks for that. The AFM has arrived today and I will put it on the car to see if it changes the running. If not then I will check out the O2 sensor, ECU, and if thats not it God knows.
I let you know how it goes
Thanks

Rez 1 · 07-04-2003, 09:29 AM

Today I replaced the Air Flow Meter and the car still idles rough

I have now ordered a O2 sensor lets see how that goes should arrive tomorrow. Fingers crossed

adrian jaye · 07-04-2003, 10:38 AM

Quote:

Originally posted by Makis
Also check if O2 sensor is operating correctly.
Do a compression test, just to eliminate any mechanical problems that the engine might have and check spark plugs.

Makei

seems same as my problem ???

changed out DME, opened it up and all looks ok, just 2 relays and a diode, but hety you never know

speak soon

Ade

Rez 1 · 07-04-2003, 03:02 PM

Ade checked your site out looks good

and crazy

like the pictures cheers mate!

adrian jaye · 07-05-2003, 08:39 AM

Quote:

Originally posted by Rez 1
Ade checked your site out looks good and crazy like the pictures cheers mate!

well its certainly been called worse,

cheers REz

A

Rez 1 · 07-11-2003, 03:12 PM

Hello all, Just came back from Ireland today and now it's back to my idling problem. Bought another O2 sensor today i will try and fit it tomorrow, see how it goes.

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