96 cirrus won't start

[Backyard]

I am stumped. Have a 1996 cirrus 2.5l v6 that has fuel pressure (50lb+/-), has compression, new plugs and wires, new crank sensor, and checked spark on 2,4,6 cylinders (easy to get at) 2 and 6 have spark but not 4 and engine cranks but will not start. Can someone HELP?

[carriedi]

no spark on #4...
I would pull the distributor cap and crank the engine. Use an incandescent test light for a ground and test for spark from the coil while cranking. You should get evenly spaced sharks as the engine cranks around. If you don't have spark for #4 you should see a bigger gap between sparks. If you get even sparking for a couple of revolutions of the motor then you may want to check the cap or rotor for why you have no spark for #4.

you have fuel pressure that's good. You say it has compression, it has some spark, does it have injector pulse? Are the injectors allowing fuel into the engine?

you could use an external fuel source and see if the engine runs on that. Be careful, you could catch the engine on fire if you are not careful.

if you can get a scanner and read you injector pulse while cranking, it should tell you if the computer is sending a signal to the injectors to open up and allow some fuel to run the engine. Or check to see if there are any codes stored in memory. you could see the rpm if the computer sees the crank sensor.

[Backyard]

I chose to pull and replace the distributor, cap ,and rotor. With all 6 plugs reachable. I checked for spark and found I am not getting spark on #1& 4. I don't know where to go next.

[carriedi]

where are you checking to see that you don't have spark?

[Backyard]

at the plugs

[carriedi]

check the wires. maybe they aren't allowing the spark through. test for spark at the cap end. Use an incandescent test light for a ground.

you said you replaced the crank sensor.. when you were installing the crank sensor, were you pushing the crank sensor so that the paper spacer was touching the flywheel? the paper spacer is what the sensor uses to set the gap.

distributors in this vehicle are known for going out or having weak spark from the coil

[Backyard]

I didn't mention that I also replaced the wires with new
What is new, Distributor, cap, rotor, wires, plugs(gaped @44),and crank senor.
End result no spark on #1&4. Starting to lean toward PCM and of course it is the most costly model based on it's part number($600.00 online) not the $170.00 model. Does it sound like my thoughts are correct.
Thank you

[carriedi]

you have already spent a lot of money on parts, you should have someone look at your car for you and see if they can verify the computer or maybe something else. A no-start is different from no spark on two cylinders. If the spark is good on four cylinders it should run. It would run badly but it should still start and run.

a lab scope could verify a crank signal that is working normally. could scope the cam sensor and scope the coil driver to see how each of the three interact together on the screen. this way if the crank signal shows six cylinder signal but the coil driver only shows four then you have a reason to do the computer.

lab scope should have:
four crank spikes then a small gap per cylinder
one coil driver signal per cylinder
and one cam signal for three cylinders up and three down

[Backyard]

I found a place that will check computer for free and if needs repair will repair it for 1/3 cost of an online replacement. Sending it out to and the turn around should be about 1 week. Have to send it to NY. Will let you know what happens.
Thanks

[carriedi]

ok, make sure you put in a detailed description of all you have done and what your problem with the car is with the computer. It will help the tech to know what area to concentrate on.

[Backyard]

Computer beyond repair, will take about 3 days to get new one.

[carriedi]

alright! hope that does it for you