My 1989 Buick Century 3.3 liter engine will crank but will not start

buick
century

#1

I have the GM shop manual and I have gone through the flow chart for an engine which cranks but does not start. I have confirmed that there is fuel pressure and spark, but the injectors do not fire when cranking. I have gotten to the final troubleshooting step of disconnecting the crank angle sensor connector, jumping A and B terminals on the connector, and momentarily grounding the jumper with a test light. The injectors fire as confirmed using the GM injector test light (in place of an injector). The flow chart conclusion is that the crank angle sensor is bad or misadjusted or the connector is making a bad connection. I have replaced the sensor twice and adjusted it using the GM adjustment tool. The connector terminals appear clean and undamaged.
Any ideas?


#2

No experience w/your car specifics, but the first thing I wonder when I read your excellently described post is that if you get spark, the crank sensor must be working. Are you certain it is possible on your car to get a spark without a working crank sensor?

If I’m on the right track, that indeed your crank sensor isn’t the problem, then what is it? hmm … well, the computer is what tells the injectors to fire. Usually the way they are configured, there is always power to the injectors, and the computer grounds them when it wants them to fire. Grounding the injector solenoid causes current to flow, which magnetically opens the injector port and allows gas to briefly spray into the intake manifold. It might be possible one or more of the injectors are faulty. Have you measured their resistance? One or more may be open. Worth a shot I guess. Does your car have a separate injector for each cylinder, or just a couple which inject into the intake manifold. If the latter, if one of them failed, it could cause this symptom. (The other type, called port injection, if one failed out of 4 or 6, the car would probably start but idle and run poorly.)

This is a tough one. Make sure the injectors have power to them, and check the injector’s resistance compared to what the shop manual says is about all I can suggest at this point. Best of luck.


#3

Sometimes the flow charts just don’t get you to where you need to go. One thing I would look at is if your valves are operating. If you can see through the oil filler with a strong light, check to see if the valves operate when the starter turns. Possible you’ve got a jumped timing chain? The book assumes you have done all the preliminary mechanical checks before hand


#4

I had a VW the other day with spark, fuel and no start (turned over all right). Turned out to be the chip in the ignition key gone bad. Another key and off it went.


#5

Does this car have the resistor in the key? If so, it could be out of tolerance and you need to add a resistor in the ignition circuit to fix your problem.


#6

There is no chip or resistor in the key.