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Buick 92 Skylark won't start -3.3 engine - ...
Sent to Car Experts October 13 11:45 AM

Buick 92 Skylark won't start -3.3 engine - changed ignition module twice - two out of three coil have no sparks - please help.

 

Optional Information:
1992 Buick Skylark 3.3

Already Tried:
changed the ignition module twice - checked sparks on all three coils - only #3 has spark - there is power to the crank sensor - there is gas in pressure on the rail -all injectors do have power.

Customer (name blocked for privacy)
Status:  Closed   Value: $15
Answer
October 13 12:01 PM (15 minutes and 27 seconds later)
         
ACCEPTEDCheck Mark
Hi!
Did you check to see what kind of signals your crank sensor is putting out? If you have voltage and a ground at the sensor, you will need to check this. You have a dual crank sensor and both parts of the sensor need to be operating to have correct spark distribution. Here is a brief description of the crank sensor operation and the reason you have spark at only the #3 coil:
Three crank signal pulses and one sync pulse are created during each crankshaft revolution. The sync pulse is used by the C3I module to begin the ignition coil firing sequence starting with the #3/6 coil. The firing starts at this coil combination because either piston #3 or #6 is on the compression stroke. Both the crank and sync pulse signals must be received by the ignition module in order for the engine to start. A bent interrupter ring or a mis-adjusted dual crank sensor could cause a no start condition, rough idle or poor performance problem.

Check to make sure you have no damage to the sensor teeth on the harmonic balancer as well.

Let me know if you need more help!


Picturettiger79 -- Auto Mechanic -- 99% Positive Feedback on 309 Car Accepts
ASE Master Certified, Certified advanced level engine performance
Reply
October 13 12:07 PM (5 minutes and 56 seconds later)
         
Reply to ttiger79's Post: Can I check the crank sensor without taking the harmonic balancer out (the scensor is behind the harmonic balancer).
Customer (name blocked for privacy)
Answer
October 13 12:17 PM (10 minutes and 42 seconds later)
         
REPLIEDCheck Mark
Yes. You will need to backprobe the 4 wire connector at the sensor itself or at the ignition module to test for a signal. There are two wires you will need to test for a signal. There is a wire white with black tracer and one that is grey with a red tracer. These are the signal wires from the crank sensor. Use a meter set to voltage and look for a "on-off" voltage signal. The white with black tracer wire is most likely going to produce a signal, the other one won't be- that's my guess.
Picturettiger79 -- Auto Mechanic -- 99% Positive Feedback on 309 Car Accepts
ASE Master Certified, Certified advanced level engine performance
Reply
October 13 3:16 PM (2 hours and 58 minutes and 15 seconds later)
         
Reply to ttiger79's Post: I need to remove the cover of the harmonic balancer –however when I try to turn the screw holding it - the harmonic balancer keeps on turning – is it a good idea to use a crowbar to keep the harmonic in place while I loosen the screw.
Customer (name blocked for privacy)
Answer
October 13 3:23 PM (7 minutes and 4 seconds later)
         
REPLIEDCheck Mark
Are you just testing the sensor or replacing it? If you are testing, I would recommend just backprobing at the ignition module.

I would not use a crowbar anywhere near the harmonic balancer. There are small "teeth" on the back side of the pulley for the crank sensor. I know this is a difficult bolt to remove. Just be patient. I would recommend removing the inspection plate for the flywheel and holding the engine from spinning at that point.

Good luck!
Picturettiger79 -- Auto Mechanic -- 99% Positive Feedback on 309 Car Accepts
ASE Master Certified, Certified advanced level engine performance
Reply
October 13 3:41 PM (18 minutes and 19 seconds later)
         
Reply to ttiger79's Post: I am going to test the crank sensor – however I still want to inspect the sensor and harmonic balancer – I guess my dilemma will be trying to hold on the engine from spinning – is there an easy way of doing that without any special tool other than my ratchet and socket?
Customer (name blocked for privacy)
Answer
October 13 4:13 PM (32 minutes and 6 seconds later)
         
ACCEPTEDCheck Mark
Yeah. Just remove the inspection plate from the transmission bellhousing on the underside of the car. You will see the flywheel behind this plate. You can use your prybar to hold the bolts that go through the flywheel. This is safer than prying on the harmonic balancer.
Picturettiger79 -- Auto Mechanic -- 99% Positive Feedback on 309 Car Accepts
ASE Master Certified, Certified advanced level engine performance
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