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Discussion Starter #1
Hello, my 1992 Buick Roadmaster sedan (69 000 miles) is not working. I'm in France. The garage mechanic told me that the injectors send too much gas. It stalls. Could you tell me what is wrong? Are the injectors are over or is it the sonde or something else...?

Thank you very much
 

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Did you pull the codes from the computer? You should do that before you do anything. The issue could be anything from an O2 sensor, to the injector, or the ground by the thermostat housing (the ground is for the O2 sensor and the computer). All will cause the engine to stall, run rich, and possibly stall. It could also be the fuel pump, and that would not give you a code.

First pull your codes. Then depending on your codes, I would start by cleaning the stud, and threaded hole for the ground (do it with the engine cold to avoid a water leak). I used a small round wire brush like you would use to clean a gun barrel, and some parts cleaner for the threaded hole, and a wire brush for the stud. Check the output of the O2 sensor, because it controls the mixture. Watch the injectors while the engine is running and after it is shut off, to check for dripping/flow pattern characteristics. It is difficult to check the fuel pressure, so I do not know how to do that without modifying the fuel line. There is supposed to be a connector that fits between the metal line and the nylon line connectors on the right by the AC compressor, but I have never seen one. There is an adapter made that can be screwed into the TBI, but you have to reshape your hard line to make it fit. Let me know what you find, I have has almost every problem possible with the LO3/5 that is possible.

Another thought, pull a plug on each side to check the color. it should be a light tan to almost white. If that is the color, it has the correct mixture, and your problem is somewhere else.
 

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I hope you used an AC Delco or a Delphi pump. Most of the other brands are junk. Do not use a Bosch.
 

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Discussion Starter #6
Battery has been changed, gas pump too, and the spark plugs too. I drove during 50 miles. The car now does not work. Would you know what's going wrong?

Thank you
 

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Have you checked for computer codes?

I would clean the ground at the thermostat housing (while the engine is cold). Remove the stud, and clean the internal threads and the threads on the stud itself. The ground is for the O2 sensor and the computer.

If that does not fix it, I would look at the O2 sensor. Check it for function before just replacing it.

Check the wiring for the plugs to make sure they are not mixed up. The firing order is on the intake manifold in front of the TBI.
 
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