nitnoy

I have a 944 2,7 liter 1989 model, it has been sitting in a rather damp environment for a couple of months, it was difficult to start at first but it did run without any problem. But since then it starts every now and then but most of the time it will not start, but when it does start it runs just fine. Yesterday I used it during the day while I did some shopping, then when I tried to started during the evening it would not start, this morning it did start, but when I tried this afternoon it would not start. Anybody knows where I should start troubleshooting?
Regards Steinar

JohnKoaWood

Let me be the first to say welcome to rennlist..

What trouble shooting has been done regarding the intermittent no start?

things to check are:
DME relay
Reference sensors
fuel pump
fuel filter
injector harness
DME temperature sensor
air flow meter
ignition cap rotor button (inside cap)
coil
DME board solder connections

Good luck and check out http://www.clarks-garage.com/ for guides to fixing MOST problem you might come accross, just click on the garage shop manual...

knfeparty

If it runs fine once it does start it's probably not a huge problem. Just a sensor is loose/broken like the speed/ref sensors. Where are you located? There is probably a member nearby that can help you.

From a fellow 2.7L owner, welcome to Rennlist!

JohnKoaWood

My bet is eastern Europe somewheres, or sub tropical Africa, but more likely Europe? (2,7 not 2.7 is a german / european thing...)

vt951

nitnoy,

When you have this problem, look and see if the tachometer needle moves at all. If it does not bounce when you crank it, that indicates that it is either the DME relay or the reference sensors (more likely the ref sensor wires/connectors). Those problems are very common and fortunately very inexpensive and easy to fix.

nitnoy

First, thanks for all the helpful answers, by the way I live in Norway and the reason I ask you for help is that the car workshop mechanics wages is way too high(that is my personal opinion) where are those sensors located ?

JohnKoaWood

At the back of the engine between the firewall and the intake!

Grandpa#3

Welcome to the forum. The link for clark's garage. Click on Shop Manual and then click on "S" and look for Speed/Reference Sensor and click on that. It will tell you all about how to check and change them.

Cheers,
Larry

nitnoy

When I was looking for the sensors I discovered some sort of sensor that was just hanging there with a cable attached, I pulled it up and it looks like it has been been attatched somewhere with a bracket that had parted but I could not find out where it belong.
I enclose a picture of it, when I look at the pictures of the sensor at "Clark garage" I see there is something that looks like the one I am talking about below the 2 sensors, what is that?

JohnKoaWood

Your picture is of the reference sensor, and part of the bracket, the other part is in the top of the bell housing, with the speed sensor attached to it!

you WILL need a new bracket, or at least have the one you have now welded and re-machined back to the original profile, but I would go for a new one... this is DEFINITELY why your car has been running badly if at all...

Good luck, I am sure there are a few folks here who can get a replacement bracket to you, and clarks garage has the adjustment procedure to follow with the new bracket..

nitnoy

Thanks for the information, encloseded is a picture of what I though was the 2 sensor, reference sensor and Speed sensor and I can not see that there is anything missing?

Grandpa#3

Hello nitnoy, The part you showed that you pulled up is not the speed or reference sensor. They are still mounted in the second picture. Go to the link below
http://www.arnnworx.com/ and click on SENSOR TOOL. The picture second from bottom will be the complete bracket with the speed &reference sensors installed along with the part ( Grey wire) still part of the complete bracket. You do not need it, I believe it was some part for testing the engine. At some point in time the bracket was broken more than likely to remove the bell housing. The last picture will show a long "U" shape. This is a modified bell housing cut so the speed/reference sensor bracket does not have to be removed in order to remove the bell housing. Below the cut you will see a half moon shape. This slid around the bottom of the Grey wire piece you pulled up. I repeat, you do not need it. This is not the reason you have a problem starting your car. Check for condensation inside the distributor cap. Make sure the rotor is on tight. The set screw can back out.

Cheers,
Larry

JohnKoaWood

http://dcauto.gotdns.com/illustration/index/203490748

P/N 12 is broken, PN 24 (911.606.108.00 Reference sensor/timing mark sender (1))
is what your picture is of, the bracket holds all 3 sensors on the S cars... IIRC neither my N/A nor my 951 have the 3 sensor setup, and I know the later 16V engines only use 1 sensor there (the other one is in the head).

I would pull the bracket and sensors, get a new bracket (944.101.321.07 PULSE SENSOR BRACKET), and re-install all 3 sensors... these need to be sorted out, or the car will never run correctly!

PS your bracket SHOULD look like this... your bracket appears the left most hole has broken off the main bracket and is attached to the sensor shown in your first pic...

nitnoy

Here is 3 more pictures taken at a different angles

Tom M'Guinn

No question about it. That's the diagnotic sensor -- not used by the motor --only used by mechanics with vintage Porsche diagnostic equipment. The other end of that sensor cable routes to the eye hook on the back of the cam tower (at least on the 951) and just sits there doing nothing. You should get a new bracket as suggested above. Before removing those two sensors, mark them very clearly so you will know which one goes to the front and which in the rear. They have to go in their original ports or the car won't run, and most harnesses are no longer marked to show which is which. You'll need to gap the rear sensor (with the washer-like spacer under it) when you reassemble it.

Try wiggling the cables to the two installed sensors next time it doesn't start. If that helps, check the harness connectors for those sensors very closely. There is a good chance those sensors are not the problem though. The symptoms you describe could be bad sensors, but the other likely problem is that your DME relay is going bad. Try tapping on it next time it doesn't start (or just replace it since they all go bad eventually anyway). Good luck.