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1987 Buick Riviera: strong smell..crankshaft..it backfires..cranks

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I have a 1987 Buick Riviera with a no start. There is a strong smell of gas in the car as well as in the crankshaft. The car, when sitting for a while, will almost want to start and it backfires once or twice before it just cranks. I have checked the catalytic converter for cloggs by taking off the bolts on the flange behind the headers. I had suspected bad gas, sprayed some either in the air intake to see if it would fire..nothing. I have spark, fuel pump and pressure are fine. Valves seem to be working while looking through oil filler. Changed fuel filter. I was checking sensors the other day and found the crankshaft sensor was working fine, 10 volts to reference and three 10 volts to signal side as engine rotates. Then checked cam sensor by backprobing, got reference voltage and then got constant voltage to the signal side, even while unpugged from sensor. Traced wires and checked resistance and all seem fine. These sensor wires go to the ignition module then to the ECM. Checked coil pack and got intermittant reading from one pack and replaced it, thought there may be a short in module so replaced that. Still no start, could it be the ECM has a short? and needs replacement. Also after new Ignition mod was replaced I am getting constant volts to crank and cam sensors on the signal and ref sides. Any suggestions would be greatly appreciated! THANKS!!!

Marc
I think its time for a compression test to see if it jumped time.If you have spark and have added fuel to the engine and it doesn't even fire you almost have to have mechanical problems.It probably wouldn't hurt to see if the spark plugs are soaked with gas and need replaced or at least dried out.Alot of times once they are wet with fuel they are done though.Hopefully you have not been using coolant and have it in the cylinders.
Customer: replied 11 years ago.
Reply to Davo's Post: Thanks for the quick answer. The pluggs are def soaked with gas but seem to still get a nice deep blue spark when dried. Def have coolant and temp on gauge was low. When this all started the car was low on power at higher speeds, exhaust was loud from front of engine. came home after aXXXXX would not start . checked fuses pulled fuel pump/inj fuse and the car started right up. drove around and ran great, went home shut it off and would not fire back up. Still don't know why I'm getting volts to my signal side of sensors.
It could be an intermittent ecm problem but you should lose spark and injector pulse if you have a crank sensor problem.Make sure when it's not starting that spark is present on at least 2 wires.Then get a noid light for your car(cheap at the auto parts)install it in an injector connection and crank the engine to test for injector pulse.When you test a crank sensor you must have the engine cranking or running and check the return signal with scope or dvom set to ac.I think you may have a bad crank sensor but check for injector pulse first.If you don't have it replace the crank sensor before condemning the ecm.If you jumper pins a and b in the aldl under the dash with the key on it will flash a code if present.Flash pause flash flash would be 12 and would repeat 2 more times folowed by other codes.Code 12 can be disreguarded because the engine is not running.
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Customer: replied 11 years ago.
Reply to Davo's Post:   Thanks. I have jumped the pins on the aldl and it opens up the diagnosis screen on my tv screen(crt) and I get "no ecm codes"
Then there are no codes stored you either have to buy a noid light and test for injector pulse or replace the crankshaft position sensor.I strongly suggest replacing the plugs I'm not so sure they are firing under compression after being soaked with fuel.A spark plug can fire great sitting on the intake or exhaust manifold but become a dud in a compression situation.I would also do a compression check while the plugs are out just to verify the mechanical condition of the engine.

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