How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Volvo
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
Type Your Volvo Question Here...
Juan Crespo is online now
A new question is answered every 9 seconds

Volvo 740: does a 91 740 have points or crank sensor? my distributor

Customer Question

does a 91 740 have points or crank sensor? my distributor is mounted on the back of the head. i am getting a weak spark at the plug end of plug wire. won't start but tries to.
Submitted: 2 years ago.
Category: Volvo
Expert:  Juan Crespo replied 2 years ago.
Hi! I’m Juan and my goal is to help you solve your car issue.
The electronic ignition ECU controls primary windings of ignition coil using signals from fuel injection ECU based on crankshaft position, engine speed and vehicle speed. Turbo models use a Hall Effect sensor, located in distributor, to determine crankshaft position and engine speed.
A weak spark can be caused by a bad coil. To check primary winding resistance, disconnect the coil from the harness and place an Ohmmeter between the coil negative (-) and positive (+) terminals; normal readings should be 0.6 - 0.8 Ohms. To check secondary, place an Ohmmeter between the coil negative (-) terminal and the high tension tower terminal (where the coil wire goes); normal readings should be 6900 - 8500 Ohms.
Engine coolant temperature sensor is used by the engine computer to determine how much fuel the engine needs to start and run under different temperatures and conditions.
Kindly accept and rate my answer now if you think the information I've provided has helped you solve your issue. Otherwise, please reply.
Best Regards.