giordon

hello everyone, im new to rennlist and i'm hoping somebody on here will be able to help me out. i purchased a 1983 944 and for some reason the car wont startup. the problem is not the battery, headlights work, radio works etc. but for some reason the sparks plugs are not putting out anything when i try to start it, everything else seems to work. i have taken it to multiple mechanics who were unable to help. i have already put in a new distributor cap, as well as replaced the speed censor, and the reference censor. if anyone has an idea on why it won't start please help, thank you.

kennedope

http://www.944online.com/cgi-bin/for...7832;start=0#0

Tried all this yet? I'm in the same position right now and looking for an answer, working my way down that list

4porsche4life

Make sure spark plugs are not foweled and test ignition coil to see if its still good... Sometimes the rotor locking screw (or locking screw to the cam) gets loose as well check that too...

peanut

welcome to the forums ...sorry to hear that you have problems though.

These cars have the Bosch Motronic fuel injection and ignition systems which are quite complex.
Basically the ECU (electronic Control Unit) controls both the fuel delivery and the ignition system dependant on the input from numerous sensors and its own programming.

First make sure that you are using a very good battery and that the earthing points are clean because if the engine doesn't crank over at at least 200rpm the ECU will prevent the car starting .


Check to see that you have fuel pressure and that fuel is getting to the inlet when the engine is cranking. Crank for half a minute then check the plugs for fuel.

If you have no fuel or spark then I would recommend that you replace the DME relay with a 3x wire bypass as described on Clarkes garage website (garage manual) this will force the fuel pump to run continuously and power up the ECU so you should get a spark and fuel.

let us know how you get on up to this point .
http://www.clarks-garage.com/

giordon

thank you all, im going to get on this first thing tomorrow and let you know where im at. the help is very much appreciated.
@kennedope have you replaced/repaired your DME relay?

kennedope

Nope, just took it out and took off the cover to have a look at the insides. All the solder points look healthy but I'm going to try the bypass today and see what happens.

peanut

Remember terminal 30 is constantly live 12v+ even with ignition off. Best to connect 87b and 87 first and 30 last or its easy to have an an accident.
Fuel pump should pump immediately with the ignition off . If it doesn't check the fuse . Good luck

giordon

hye guys the dme relay was the solution, thanks for all the help

giordon

there is another problem though unfortunately.. my car is overheating now. i drove a mile down the road and the temp skyrocketed. any ideas?

giordon

coolant is good, fans are working, or at least one fan is anyway... could the problem be the one fan not turnig on? or perhaps a bad thermostat? maybe the a/c cooling fan relay?

mro763

If its overheating; Possible thermostate or water pump. Water pumps are famous for going out in these cars.I know the feeling, you fix one thing and then another things goes wrong. Good luck!

djantlive

must be a blockage of coolant, bad thermostat or water pump. i would change the thermostat first.

peanut

glad to hear its starting and running .
In future if you fit the simple 3x way bypass as suggested it would have started and ran immediately, if the DME relay was faulty. The 3x way bypass is an extremely reliable diagnostic

oefporschelover

i installed a fuel pump and nothing

jhowell371

While complicated this system can broken down simply and checked step by step. Do you have tach bounce on cranking the engine? If yes do you have spark? If so have you sprayed starting fluid into the intake to see if it tries to start? If it tries to start on ether than you have a fuel problem. Do you have pressure at the rail? If not why isn't the pump running? Have you replaced the DME relay or tried the aforementioned jumper? Have you tried a noid light on the injectors to check for power to injectors? Have you checked your speed and reference sensor connections? Sometimes the connectors are bad and just wiggling has started many a car. Have you checked the sensors themselves with an OHM meter? As you can see there is a lot to check but the problem has to be there somewhere.