1986 Buick Park Avenue No Spark

Have you checked all of the fuses, relays and circuit breakers. There are 1 or more of these that control the computer and spark control. Also MAF sensor, MAP sensor as well as other sensors may fault out and cause the computer to shut down the ignition system. Do you have a check engine light on or have you checked for any trouble codes?

First complaint stated no spark. Additional complaint stated no fuel delivery from injectors.

Fuel pressure at engine should read 40-45 psi. If not, filter could be plugged or pump bad.

Are you sure your check engine /service engine light is actually operating when you turn key on? If not then you need to be sure you checked for codes with an approved code reader.

No codes would indicate at least 2 possible scenarios. One is either the computer (ECM/PCM) has failed completely and is not delivering any codes.
The other is that what ever is causeing the problem has nothing to do directly with the computer in order to operate ie. Anything mechanical or electrically independant of computer control.

To not have spark or fuel delivery you should have at least one of the following codes:
19 Crankshaft position sensor or circuit.
33, 34 Mass Air Flow sensor or circuit.
41, 51 PROM, MEM-CAL or ECM problem.
42 Electronic Spark Timing circuit.
52, 53 CALPAK or ECM problem.
54 Fuel Pump circuit.
63, 64 Manifold Absolute Pressure sensor.

Humor me a little and try this: Spray a little carb cleaner or starting fluid into the throttle body and then see if the engine tries to fire. If it does then you have a fuel delivery problem. If it does not fire then we are back to the previous discussion.

Other than the above suggestions, the only other thing to do would be to take it to the dealer service dept. They have a way to coax hidden codes out of the system.

Give feedback and let me know what happens.

Code 12 means that the computer is in diagnostic mode. This code will come up 3 times in succesion. After that any other codes stored will also come up 3 times each. Did you allow enough time for this to happen or did you stop at the 12 code? ( Some people will see this code twice and think it is the only code set since other codes did not follow the first 12 code set.)

I have tried to remember in the past when I have come upon a no code no spark situation. I seem to remember about, a year ago, a 92 Park Avenue that would start cold but then would die and not start again until engine cooled again. No codes were present. No spark and no fuel. Checked everything I could think of. Finally I remembered an 85 Pontiac that was acting similar a few years earlier. When the engine got hot it would stop. I placed an ice cube on the Mass Air Flow sensor and the car started right up. I replaced the sensor and had no more problems. The circuits inside the sensor housing were getting hot and failing. The ice cooled the sensor and it went back to working.

I was not around any ice cubes with the Buick so I took a water hose and startes running it over the sensors starting with the MAF sensor. I eliminated over heated sensors one at a time cooling each seperately and trying the engine. When I came to the Crank Shaft Position sensor and cooled it, the car started right up. It may depend on how the sensor fails as to wether a code is set.

The CSP sensor communicates with the computer to determine when the crankshaft is really turning and when to start ignition and maybe the injectors to fire also.

The MAF sensor tells the computer how much air flow and sometimes incorporates the air temps also to determine how much fuel to deliver.

Both of these go through the powertrain control system. If the CSP does not give a signal that the crank is turning, the computer has no reason to request spark or fuel. If the MAF sensor does not give a signal that air is coming into the engine, the computer receives the same no command response.

Does any of this make sense to you? I put my money at this time on the crank sensor, It is not the easiest to change but is not as expensive as MAF sensor.

Mull this over a little. I can't see you checking the crank sensor since it is behind the harmonic balancer!

I am with you 100%. You can do the test to verify
( if you have an oscilliscope available ) or you can just replace the CSP.

Keep me informed. Good luck.

There is a special tool need to set the correct dimension from the center line os the crankshaft to the sensor.

If you do not have this tool it is almost impossible to set this dimension.

I have an engineering degree and with the help of dial calipers I was able to calculate the dimensions necessary from measureing the distance from the crank center to the veins of the balancer and then to the slots of the CSP sensor allowing the veins to fall in the center of the slots.

If you attempt this without proper settings, the CPS will probably get ripped apart and the harmonic balancer veins that trip the sensor may be damaged also.

Check with a good parts store to see if they have this tool available. If not, check with your friend to see if he has one in his tool box.

Great addition to this thread! Please feel free to help out whenever you are on the site. :)

Cheers, Ken