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1989 944 S2 - Irratic Idle and juddering at low speeds
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Author:  ben944 [ Fri Jan 29, 2010 7:00 pm ]
Post subject:  1989 944 S2 - Irratic Idle and juddering at low speeds
Hi All,

Last week I suffered with a intermittent problem (the worst type of problem). When the car was cold, I'd driven about 1/2 mile and came to a set of traffic lights. The S2 then started to idle wildly between 800 rpm and 1400 rpm, almost stalling at times. After setting off, a short time later the car then started juddering and losing power and then springing back into life. This juddering was occurring in traffic at about 25 -30 mph. By the time I'd had a short run up the motorway to work the problem had cleared. The car incidentally was fine at motorway speeds and pulls like a train at all other times.

A week has now passed and today it did the exact same thing again but the juddering was far worse. The car was cold I hasten to add. Its almost like some sort of fueling problem. So what am I looking at? DME? MAF? I collegue of mine at work said he had a similar problem with his Z3 which turned out to be his cam sensor. Does the S2 have a cam sensor???

I have a spare DME relay I can substitute for the one fitted, but I'm not convinced that may cure it. Any ideas??? The only thing I changed recently was the type of fuel I'm using. I was using Shell V-Power but due to it getting quite costly I'm back on the normal Shell Unleaded. Surely that can't be the problem?

Thanks in advance. Missus has started going banana's already! She's seeing £ signs fluttering out of the bank account and refering to my beloved car as that "F#*king thing" again!!

Ben :bounce:
Author:  tr7v8 [ Fri Jan 29, 2010 7:19 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
When did it last have the ignition looked at? It sounds like wet somewhere it shouldn't be or dodgy leads. When it warms up they dry out & it is OK.
Another left field idea is a very damp air filter icing up either itself or the AFM.
Author:  ben944 [ Fri Jan 29, 2010 7:34 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
tr7v8 wrote:
When did it last have the ignition looked at? It sounds like wet somewhere it shouldn't be or dodgy leads. When it warms up they dry out & it is OK.
Another left field idea is a very damp air filter icing up either itself or the AFM.


Hi Jim,

I've got no idea when the ignition was last looked at as I've only had the car around 18 months. It has rained overnight on both occassions when I've had this problem - could be a link. Is there any area and I can spray with WD-40 perhaps? Or just give everything electrical a good dousing?

Side issue - I noticed the other day that the plastic shield in front of the windscreen covereing the wiper motors etc has a split in it. This could cause water to run in below the windscreen. Isn't the ECU situated around that area???

Ben :bounce:
Author:  deLUX [ Fri Jan 29, 2010 7:48 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
Mine did this and it was down to a ill fitted Distributor Cap - attached it correctly and hey presto
Author:  tr7v8 [ Fri Jan 29, 2010 11:06 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
ben944 wrote:
tr7v8 wrote:
When did it last have the ignition looked at? It sounds like wet somewhere it shouldn't be or dodgy leads. When it warms up they dry out & it is OK.
Another left field idea is a very damp air filter icing up either itself or the AFM.


Hi Jim,

I've got no idea when the ignition was last looked at as I've only had the car around 18 months. It has rained overnight on both occassions when I've had this problem - could be a link. Is there any area and I can spray with WD-40 perhaps? Or just give everything electrical a good dousing?

Side issue - I noticed the other day that the plastic shield in front of the windscreen covereing the wiper motors etc has a split in it. This could cause water to run in below the windscreen. Isn't the ECU situated around that area???

Ben :bounce:

Guarantee it is the leads,try lifting the bonnet at night with the engine running & look down the leads & see if there are sparks jumping off them. Check the dizzy cap, rotor arm & plugs at the same time.

ECU is in the passenger footwell so should be OK. That piece of plastic is best bought from an OPC but shouldn't cause any real issues.
Author:  ben944 [ Sat Jan 30, 2010 10:24 am ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
Hi,

Thanks for the input so far. Quick update - I've replaced the DME relay (just in case) and have pulled off the spark plug leads and given the plug ends and spark plug tops a good spray with WD-40.

I'll see how it runs on the journey home from work tonight.

Ben :bounce:
Author:  albi [ Sat Jan 30, 2010 8:52 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
your worse scenario on this could be a sticking valve. i had a rover 800 about 15 years ago, that did exacly that and it had to have the head whipped off to sort :shock: tbh, i think yours is damp related ignition items fromwhat you have said :D
Author:  J.J. [ Sat Jan 30, 2010 10:54 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
Missus has started going banana's already! She's seeing £ signs fluttering out of the bank account and refering to my beloved car as that "F#*king thing" again!!

Sounds familiar! Replaced the leads first job on mine. Showed as faulty on the dyno. Money well spent. GSF Huddersfield do good oem ones for not a lot.
Author:  AlpineTurbo [ Sun Jan 31, 2010 5:04 am ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
But it's an S2. Much pricier leads.

GSF do them for £99+VAT when I last checked although if you're a friendly face met by a nice salesman there, they can be obtained for £98 all in. :o

GSF seem to have a problem getting them (there are 2 in Heathrow but they're not sending them!). In the end I went to PCT (Autobahn) http://www.pctcars.co.uk/contact.htm where they sold them to me for £110.45 all in. They were the cheapest by far (Porsche wanted £180, Berlyn £146, Porscheshop ~£135, and the rest didn't seem to do them. When I checked GSF and PCT do Beru leads, just like what's on yours (They even have a 944 part number on them with the Porsche logo blatently scribbled out :lol: .)

If it helps, I can arrange a group buy for the leads but by Lumention for a much reduced price. But the Beru leads I got seem to have a Kevlar/CF effect on them, and I figured that if they lasted 20 years, the new ones should be good for another 20.
Author:  ben944 [ Sun Jan 31, 2010 4:16 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
tr7v8 wrote:
ben944 wrote:
tr7v8 wrote:
When did it last have the ignition looked at? It sounds like wet somewhere it shouldn't be or dodgy leads. When it warms up they dry out & it is OK.
Another left field idea is a very damp air filter icing up either itself or the AFM.


Hi Jim,

I've got no idea when the ignition was last looked at as I've only had the car around 18 months. It has rained overnight on both occassions when I've had this problem - could be a link. Is there any area and I can spray with WD-40 perhaps? Or just give everything electrical a good dousing?

Side issue - I noticed the other day that the plastic shield in front of the windscreen covereing the wiper motors etc has a split in it. This could cause water to run in below the windscreen. Isn't the ECU situated around that area???

Ben :bounce:

Guarantee it is the leads,try lifting the bonnet at night with the engine running & look down the leads & see if there are sparks jumping off them. Check the dizzy cap, rotor arm & plugs at the same time.

ECU is in the passenger footwell so should be OK. That piece of plastic is best bought from an OPC but shouldn't cause any real issues.


Hi Jim,

I tried your trick last night of running the engine in the dark with the bonnet open. No sparks I'm afraid. This problem is very intermittent. I've also been led to believe it could be an injector or possibly a sticky AFM. I could buy a set of leads but I think I'd prefer to get the problem diagnosed before spending money with trial and error parts. If its the leads, great - you've sorted out the problem for around £130. But what if it doesn't cure the problem. You've just spent a £130 and now got a spare set of leads and the original problem.

Ben :bounce:
Author:  AlpineTurbo [ Tue Feb 02, 2010 11:35 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
In that case, spray a fine mist of water (only a little) over the leads at night time and look for 'fireflies'.

Check the rotor arm, although I'd have said leads more so. As a cheap fix, when were your plugs last changed? They need to be changed every 12,000 miles on an S2.
Author:  Richy_S [ Wed Feb 03, 2010 7:10 pm ]
Post subject:  Re: 1989 944 S2 - Irratic Idle and juddering at low speeds
I know it only happens when cold but still worth checking your throttle position switch and idle valve.

Check Clarks garage for procedures.

Rich
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