[jnewell745]

Hi, I am new to this forum so I hope I am posting correctly.
I have a 1996 306 XN petrol which I drove on to my driveway, but the following morning it wouldn't start. I think I have traced the reason to no spark, using a timing light. Why it won't spark I don't know. The immobiliser seems to work OK - put in the code and the light goes green. The engine will crank but doesn't fire at all. I have tried spraying quick start into the air intake whilst cranking to try and rule out a fuelling problem. None of the cylinders have a spark. I believe the coil is in two sections and it is unlikely that both would fail at the same time. Is there a way to remove the immobiliser from the circuit? Any suggestions on tracking this problem would be gratefully received. Thanks.

 

[reliable406]

You say the immobiliser is ok but you want to remove it !!

If you have no spark you need to find why you have no spark if it is a keypad immobiliser and the light goes green then its not likely to be the issue.

could be a crank sensor issue as without a crank signal you wont get a spark.

 

[jnewell745]

Hi reliable406. Thanks for the response. I don't especially want to remove the immobiliser, I just thought that if there was a relatively easy way to bypass it, it would remove one possibility from the equations. It is a keypad type and it appears to be functioning but I'm always a bit suspicious of auto electronics. How can I test the crankshaft sensor? If I connected a test meter to it whilst cranking would I expect to see anything eg a 12v pulse, I can't find any reference to the crankshaft sensor in the Haynes manual, but there is an engine speed sensor shown on the circuit diagram. Would this be the crankshaft sensor? Thanks for your help.

 

[reliable406]

Yes crank sensor engine speed sensor same thing you cant really test it with a meter as they tend to run at 5 volts not 12 and the signal is very small.

The keypad immobiliser can be disabled by activating it IE get the car working FIRST once you have fixed the real issue you just unplug the wires on the underside of the keypad and the immobiliser will no longer work but as i say its not the issue and dont attempt to mess around with it till you get engine running again.

 

[jnewell745]

OK Thanks. I'll get a new crankshaft sensor and try swapping it out.

 

[reliable406]

Check the wiring to the crank sensor first its just as likely to be bad wiring/connections