1984 lux no spark

[porche magic]

My old 944 has been sitting for some time and has no spark,,all is clean on plugs ,dist cap and coil ,,i have a voltage getting to the coil but no spark,,what should the voltage be coming into the coil and how much coming out ? any help would be great,,Colin.

 

[Hairyarse]

Got a similar issue with mine that I'm yet to have time to sort, general opinion is it could well be the crank sensor. From memory, the rev counter should 'bounce' slightly when turning over the engine, if it doesn't then it's most likely the sensor

 

[porche magic]

wow that was a fast answere,where would that sensor be located?"dont say the crank lol"any idea on the voltages ?,want to rule out the coil and dont want to fry my e meter first try )

ORIGINAL: Hairyarse

Got a similar issue with mine that I'm yet to have time to sort, general opinion is it could well be the crank sensor. From memory, the rev counter should 'bounce' slightly when turning over the engine, if it doesn't then it's most likely the sensor

 

[robwright]

Speed and reference sensors are located on the top of the clutch housing at the back of the engine. There is a guide for checking them on Clark's garage, www.clarks-garage.com Go to shop manual and sensors.

 

[porche magic]

THank you very much,not sure ill need to do this yet until i have the voltages to check.

 

[Mike_Pollock]

Is the tacho needle bouncing as it turns over?
If its not then check the crank sensor.
If it is then check the DME relay.

 

[barks944]

The tacho output is actually a direct take off the ignition output. If the DME is trying to spark the coil the tacho should bounce a little. The DME grounds the coil to put it into dwell so with the ignition on you should see 12V to ground on one side of the coil and 0V on the other. You can't measure the spark voltage with a meter, you can pull a plug and lie it onto the engine block and look for a spark when cranking.

You should hear the fuel pump running when you crank the engine. Get someone to stand near the rear of the car and listen for the electric fuel pump during cranking.

 

[Northern924]

Its been said but don't put to much importance on the coil being at fault, it very rarely is.

Ref. sensor & DME relay ARE common fail points these engines and if its been sat that long you should really check them first. If you look at the Clarkes page it will help you a lot, and there is a way to test them with a multimeter.

Check that there is a click from the DME when the ignition is turned on, and you should then feel a slight one when cranking, where abouts are you?

 

[porche magic]

Looks like the crank sensor,was hoping for a quick fix to fire her up for sale,,,its been sitting for a few years now"very sad"changed into fifth gear one day and it lost drive,went back a gear and nothing,,,gearbox problem i think,,,was riding motocross and doing some karting back then and needed my other car on the road to do the sports so she sat waiting for me but after the wife and kids and job get in the way it just didnt get done ,This was my first car and very special to me,even now its going on ebay still dont want to see her go,,its the nice silver or blue as porsche call it with cookie cutters and polished dish,,,so sad,,you guys know how i feel,,,its my baby.

 

[Northern924]

Don't take this the wrong way but if its you baby, why sell it? Gearbox will cost you about £100 if it is that could just as easily be the clutch, and the crank sensor can be picked up for 20, hell you can even take out the DG one and swap it into the BG slot to get it started, not a massive amount of work and not to much expense

 

[porche magic]

I dont really have a choice,cant afford two cars right now and i need a familly car on the road as i have 4 kids and the head went on my other car and its an engine out job of £800.00,,so have to get real and get a tidy familly car,,,maybe in the future i can get another 944 or maybe a 928.